INTERNATIONAL UNION OF PURE AND APPLIED CHEMISTRY

10th INTERNATIONAL CONFERENCE ERPOS

ELECTRICAL AND RELATED PROPERTIES OF ORGANIC SOLIDS AND POLYMERS

Cargèse, 10 – 15 July 2005

UNIVERSITY OF ANGERS and INSTITUTE OF SCIENTIFIC STUDIES CARGESE

INTERNATIONAL UNION OF PURE AND APPLIED CHEMISTRY

10th INTERNATIONAL CONFERENCE ERPOS

ELECTRICAL AND RELATED PROPERTIES OF ORGANIC SOLIDS AND POLYMERS

Cargèse, 10 – 15 July 2005

PRAGRAMME BOOKLET

UNIVERSITY OF ANGERS and INSTITUTE OF SCIENTIFIC STUDIES CARGESE

The 10th International Conference ERPOS under the auspices of the

INTERNATIONAL UNION OF PURE AND APPLIED CHEMISTRY Macromolecular Division

Organized by the UNIVERSITY OF ANGERS and INSTITUTE OF SCIENTIFIC STUDIES OF CARGESE Élisabeth Dubois-Violette Director of the Institute André Monteil Director of POMA at Univ. Angers Sylvie Dabos-Seignon Online Registrations B. Sahraoui Organisation committee G. Aldea, I. Rau, S. Ahmadi International Relationships D. Guichaoua web site management Marie-France Etienne Administration CONTACT

ERPOS SECRETARIAT Laboratoire POMA Université d’Angers 2 Boulevard Lavoisier F – 49045, ANGERS, FRANCE Telephone: +332 4173 5434 Telefax: +332 4173 5216 E-mail: [email protected] Institut d’Études Scientifiques de Cargèse, Menasina F-20130, Cargèse.

INTERNATIONAL COMMITTEE H. Cailleau (Rennes, France) B. Munn (Manchester, UK) S.T. Lee (Hong-Kong, China) K. Yoshino (Osaka, Japan) R. Metzger (Tuscaloosa, USA) C. Taliani (Bologna, Italy) J. G. Grote (AirForce Research Labs, USA) J.I. Jin (Seoul, Korea) J. Sworakowski (Wroclaw, Poland) A. Miniewicz (Wroclaw, Poland) J. Zyss (ENS-Cachan, France) W. Huang (Shanghai, China)

Conference Chairman Jean-Michel Nunzi (Angers, France)

Conference Co - chairman François Kajzar (CEA Saclay, France)

Local Programme Committee Centre National de la Recherche Scientifique Institut d’Études Scientifiques de Cargèse 20130 Cargèse

The meeting has been generously sponsored by

INTERNATIONAL UNION OF PURE AND APPLIED CHEMISTRY OFFICE OF NAVAL RESEARCH GLOBAL

GROUPE FRANÇAIS D'ETUDES ET D'APPLICATIONS DES POLYMERES

ESF COST P8

CEA/DRT/LITEN

INSTITUT D’ETUDES SCIENTIFIQUES DE CARGESE

MAIN LECTURES The presentation time for each lecture is 30 min. The following international experts have accepted the invitation to present main lectures: N.S. Sariciftci, plenary Austria

Y. Koike, plenary Japan

N. Peyghambarian USA

K.S. Lee Korea

B.C. Simionescu Romania

A. Moliton France

T. Kaino Japan

H. Baessler Germany

A. Miniewicz Poland

T. Kobayashi Japan

J. Grote USA

Y. Shirota Japan

H.J. Eichler Germany

A. Persoons Belgium

T. Watanabe Japan

H. Cailleau France

K.D. Singer USA

S. Schrader Germany

N. Kirova France

A. Mikawa Japan

PUBLICATION Summaries of lectures and communications will appear in the Programme Booklet. Peer-reviewed full texts of the presentations will be published in a special volume of Nonlinear Optics, Quantum Optics: Concepts in Modern Optics (Old City Publishing).

CONFERENCE SCHEDULE Sunday, July 10, 2005, Registration Monday, July 11, 2005, Session A: Optical storage materials Chairman: J-M Nunzi A 083 A 090 A 092

A 094

08:30 MINIEWICZ Andrzej, On the mechanisms of light-induced optical anisotropy in organic and bioorganic systems. [email protected] (invited) 09:00 TAJITSU Yoshiro, High speed light modulation of chiral polymer film. [email protected] 09:20 MANDOWSKA Ewa, Mandowski A, J. Œwitek, W. Mazela, P. Czub, J. Pielichowski, Dependence of luminescence properties on preparation conditions of epoxy resin modified by carbazole derivative. [email protected] 09:40 LAPINSKI Andrzej, M. Golub, V. A. Starodub Spectral and electrical investigation of the spin-ladder candidate (N-C2H5-Pz)(TCNQ)2 [email protected]

10:00 -Coffee break A 103 A 110

A 113

A 115 A 121

10:30 EICHLER H. J. [email protected] (invited) 11:00 KOBAYASHI Takayoshi, Yoshiharu Yuasa, and Mitsuhiro Ikuta Sub-5-fs real-time spectroscopy to clarify the mechanism of ultrafast optical nonlinearity in a conjugated polymer. [email protected] (invited) 11:30 VEMBRIS Aivars, A. Tokmakovs, E. Laizane, I. Muzikante, Influence of the structure of azo dyes on cis- trans photoisomerization kinetics in solution, polymer matrix and LB films. [email protected] 11:50 KUCHARSKI Stanislaw, E. Ortyl,R. Janik, Photochromic Polymer Films with Single and Binary Chromophore System [email protected] 12:10 KOBAYASHI Takeyuki, Visible and Near-Infrared Light Amplification and Lasing in Luminescent Polymer Microstructures. [email protected]

12:30-15:30 BREAK -LUNCH 15:30 Coffee break Session B: “Green“ functional materials and electronics Chairman: Miniewicz A. B 160

16:00 GROTE James, Emily Heckman, Josh Hagen, Perry Yaney, Guru Subramanyam Andrew Steckl, Darnell Diggs, John Zetts, Noaya Ogata, Paras Prasad, Frank Hopkins, Photonic Materials Based on DNA [Deoxyribonucleic Acid]. [email protected] (invited)

B 163 B 165

B 171

B 173 B 175

B 181

B 183 B 185 B 191 B 193

16:30 BOGDAL Dariuz, Carbazole based photorefractive polymeric materials [email protected] (invited) 16:50 ALDEA Gabriela, Gabrielle-Charlotte Chitanu, Bogdan C. Simionescu, Jack Cousseau, Sylvie Dabos-Seignon, Jean-Michel Nunzi, Design and Synthesis of Novel [60] Fullerene Derivatives for SelfAssembly 17:10 BOITEUX G., M. Chouiki, J. Davenas, C. Boullanger, G. Seytre, P. Cassagnau, J. Ulanski, A. Mierczynska, Y.V. Mamunya, P. Pissis, and J.K. Jeszka - Smart materials based on polymers, [email protected] 17:30 CHITANU Gabrielle Charlotte, Maleic anhydride copolymers as multi-functional materials for environment protection [email protected] (invited). 17:50 HIORNS R.C, A Khoukh, H Preudhomme, H Martinez, J. Leroy, R. De Bettignies, M Firon, C Sentein, C Dagron-Lartigau New copolymers based on poly(3-alkylthiophene) and fullerene for photovoltaic applications 18:10 PIVRIKAS Almantas, G. Juška, K. Arlauskas, A. J. Mozer, M. Scharber, N.S. Sariciftci, and R. Österbacka1, [email protected] Charge carrier transport and recombination in -conjugated polymers and bulk heterojunction solar cells. 18:30 SALIKHOV Renat, Lachinov A., Bunakov A., Charge cariers transport in organic-inorganic multilayer structures. [email protected] 18:50 SIMIONESCU B. C., G. David, Functional micro- and nanoparticles based on N-acyliminoethylene oligomers. [email protected] (invited) 19:10 COUSSEAU J., Towards novel C60-based organic materials from C602- anion chemistry. [email protected] 19:30 TAMEEV Alek, Charge mobility in polymer systems. [email protected]

EVENING POSTER SESSION 1: 20:30 – 22.30 P01

AHMADI KANDJANI Sohrab, R. Barille , S. Dabos-Seignon , J.-M. Nunzi,The effect of light polarization on the self-organized surface relief grating in an azo-polymer

P02

ALEM Salima, Molecular model (T6:C60) for polymer-fullerene bulk heterojunction solar cells

P03

BARLIER Vincent, J. DAVENAS, V.BOUNOR-LEGARÉ, G.BOITEUX, PVK/TiO2 nanocomposites :a new approach based on "in situ" synthesis of inorganic particles in melt polymer

P04

Kokou D. Dorkenoo, Stéphane Klein, Virginie Stortz, Alain Fort, ORGANIC DFB LASERS CREATED THROUGH PHOTOINDUCED POLYMERIZATION

P05

G. Bazylak, D. Niewiarowska, I. Szymanska, Nanosized and copper intercalated chalcogenides as components of polymeric membrane and carbon paste electrodes for detection of nitroimidazole containing drugs

P06

BOGDAL Dariuz, Carbazole and bipyridine copolymers for application as a novel phorefractive materials.

P07

S.W.Chan, A.B. Djurisic, J-M. Nunzi, Second Harmonic Generation (SHG) of Zinc Oxide (ZnO) nanorods.

P08

R Dabirian, C. A. van Walree, L. W. Jenneskens "End-functionalized oligo(cyclohexylidenes) as electron donors in charge-transfer complexes with TCNE”.

P09

D. Gindre, J.M. Nunzi, A. Vesperini, LIFETIME MEASUREMENT OF POLARIZATION GRATING IN POLYMER THIN FILM BY SPECTRAL ANALYSIS OF DISTRIBUTED FEEDBACK DYE LASER EMISSION

P10

GLOWACKI IRENEUSZ Photogeneration of charge carriers in polysilanes with N-phenothiazine and their complexes with C60

P11

M. Obarowska, R. Signerski, J. Godlewski, CHARGE CARRIER PHOTOGENERATION IN MOLECULAR MATERIALS IN PRESENCE OF CARRIER TRAPPING SITES

P12

Pascale JOLINAT, Max-José MABIALA, Pierre DESTRUEL, Isabelle SEGUY, Guy ABLART, Measurement of electric field distribution in organic light-emitting diodes by electroabsorption spectroscopy.

P13

G. Juška, K. Arlauskas, G. Sliaužys, M. Scharber, A. Pivrikas and R. Osterbacka, Recombination of injected charge carriers in bulk heterojunction solar cells

P14

MAAROUFI ABDEL-KARIM, Positive Temperature Coefficient (PTC) effect of Polymeric matrix loaded with metallic fillers

P15

E. Mandowska, A. Mandowski, J. Œwitek, W. Mazela, P. Czub, J. Pielichowski, Jablonski diagram and energy transfer mechanism for epoxy resin modified by carbazole derivative.

P16

MENSIK Miroslav, Pfleger J., Nespurek S., Raman Spectroscopy of Molecular Systems with Strong Electron-Phonon Coupling.

P17

I. OLEJNICZAK, B. Gromadziński, A. Graja, T. Devic, and P. Batail Optical study of the metal-insulator transition in β-(EDT-TTFI2)2(Pb5/6 1/6I2)3 AND β-(EDT-TTF-I2)2(Pb2/3+xAg1/3-2x xI2)3

P18

K. Pacheco, S. Ahmadi, G. Aldea and J. M. Nunzi, PVA/Acrydine Orange as recording material for Holography

P19

Irina Popescu, Gabrielle Charlotte Chitanu, Adrian Carpov, Maleic polymers derivatives as potential photosensitive materials

P20

RAU Ileana, Pawel Armatys, Francois Kajzar, Roberto Centore, Antonio Carella, HIGH GLASS TRANSITION TEMPERATURE POLYURETHANES FUNCTIONALIZED WITH EFFICIENT CT CHROMOPHORES FOR SECOND ORDER NONLINEAR OPTICS

P21

SUFLET Dana Mihaela, Gabrielle Charlotte Chitanu New phosphorylated polysaccharides for advanced applications

P22

R. Świetlik, A. Łapiński, M. Połomska, A. Ota and L. Ouahab, Spectroscopic studies of the charge ordering effect in the monoclinic form of conducting BEDT-TTF salts with Co(CN)6 and Fe(CN)6 anions

P23

TOMAN Petr, S. Nešpùrek, M. Weiter, M. Vala, J. Sworakowski, W. Bartkowiak, Photoswitching in polymers with photochromic dipolar species

P24

WEITER Martin, Martin Vala, Karolína Èerná, Stanislav Nešpùrek, Dopant-assisted carrier photogeneration in conjugated polymers

P25

ZHIVKOV Ivaylo, M. Biler, S. Nespurek, Poly(pheylene-vinylene): detection of localized states

Tuesday, July 12, 2005 – Session C: Polymers for broad band information technologies Chairman: Kaino T. C 081 C 084 C 091 C 094

08:15 KOIKE Y, Recent POF Technology for Broadband Society. (invited) 08:45 MIKAWA A., POF Today and Future. [email protected] (invited) 09:15 PEYGHAMBARIAN Nasser [email protected] (invited) 09:45 SUGIHARA Okihiro, Shuhei Yasuda, Toshikuni Kaino, Waveguide Loss Measurement Using Self-Written Waveguide Technique, [email protected]

10:05 -Coffee break C 103 C 110 C 112 C 114

10:30 SINGER K., Liquid Crystals for Optoelectronics. [email protected] (invited) 11:00 Tanaka C., Development of Advanced Perfluorinated GI-POF for Next Generation FTTH. [email protected] 11:20 Wang Jun, Fei Chen, Dennis Lo and K.Y. Wong, One-photon, two-photon pumped distributed feedback zirconia waveguide Lasers 11:40 CAILLEAU Hervé (invited)

12:30-15:30 BREAK – LUNCH 15:30 Coffee break Session D: Nano-bio-photonics Chairman: Grote J. D 160 D 163 D 170 D 173 D 180 D 182 D 184

D 190

16:00 KAINO T., Development of Polymer Optical Waveguides for the Next Generation FTTH Systems. (invited) 16:30 WATANABE T., Novel Polarizer Based on Anisotropic Light Scattering for High-Quality Display. [email protected] (invited) 17:00 LEE, K.S. "Recent Advances in Two-Photon Absorption Materials and Applications" (invited) 17:30 PERSOONS A, Nonlinear optical properties of polythiophene films: towards magneto-optical devices. [email protected] (invited) 18:00 DJURISIC Aleksandra, C. H. Cheung, Y. H. Leung, D. Li, H. Wang, M. H. Xie, and W. K. Chan, Organic and inorganic nanostructures for optoelectronic devices. [email protected] 18:20 MAABOU Serge, L. C. Fai, V. Teboul, I. Nsangou, A. Monteil, Polaron in quantum dots and wire. [email protected] 18:40 Hubert C., S. Kostcheev, J. Grand, G. Lerondel, A. Vial,R. Bachelot, P. Royer,S. H. Chang, S. K. Gray, G. P. Wiederrecht, G. C. Schatz, Near-field photochemical imaging of noble metal nano-objects using an azodye polymer. 19:00 SZOSTAK Magdalena, B. Kozankiewicz, J. Lipiński,

Polaronic photoemission and chiral packing of nitroanilines m-NA, pNA AND MNA crystals. [email protected] EVENING POSTER SESSION 2: 20:30 – 22.30 P26

Ahmadi Kandjani Sohrab, S. W. Chan, R. Barille, S. Dabos-Seignon, J.-M. Nunzi, Holographic and all-optical poling gratings in Saffron.

P27

H. Aarab, BAITOUL Mimouna, J. Wéry, S. Lefrant, E. Faulques Resonant Raman scattering, infrared spectroscopy and electrical properties of poly (p-phenylene vinylene) and Single walled carbon nanotubes composites

P28

Kokou D. Dorkenoo, Alberto Barsella, Daniel Acker, Alain Fort, Stéphane Klein, ELABORATION OF OPTICAL INTEGRATED DEVICES BY MULTIPHOTON POLYMERIZATION PROCESSES IN DOPED PHOTOPOLYMERS

P29

Jean-Philippe Bombenger, Loïc Mager, Jean-Pierre Vola, Alain Fort, Christiane Carré, QUADRATIC NLO PROPERTIES OF PHOTOPATTERNED FUNCTIONALIZED POLYMERS

P30

M. Biler, H. Vrbova, S. Nespurek, Poly[(ethylenedioxy)thiophene] Conductive Films: A New Preparative Method.

P31

CHAPRON David, Photoinduced Absorption and Charge Transfert in Semiconducting Polymers

P32

CHEN Yu, Mohamed EI-Khouly, Mikio Sasaki Yasuyuki Araki, Osamu Ito, Axially substituted titanium Pc-C60 dyad designed for nonlinear optics

P33

DOBULANS Rorijs, Janis Latvels, Inta Muzikante, Egils Fonavs, Andrej Tokmakov, Marcel Bouvet Molecular Diode of Metalloftalocyanines for Ammonia Sensing

P34

GLOWACKI IRENEUSZ, Oxidation processes of conjugated polymers seen by thermolumninescence

P35

K. Porath, D. Kotowski, R. Signerski, GODLEWSKI JAN, "ESTIMATION OF THE SPATIAL AND ENERGETICAL DISTRIBUTION OF TRAPS IN THIN ORGANIC LAYERS"

P36

HAYAKAWA Yoshio, T. ONO, N. YASUDA, A. SEKINE, H.UEKUSA, Y. OHASHI, Fluorine-based crystal engineering: Novel molecular alignment of diacetylenes with hexafluoropropene trimer segments

P37

KHOSHSIMA Habib, H. Tajalli, A. Ghanadzadeh, Investigation of temperature dependence of Kerr constants and nonlinear susceptibilities χ(3) of some nematic liquid Crystals.

P38

Lewanowicz Aleksandra, Spectral features of anil-type system in frozen matrices

P39

MAKINO Kenji, Takaaki Ishigure and Yasuhiro Koike, Analysis on GI-POF Link Performance under Static Fiber Bending

P40

MANDOWSKI Arkadiusz, Theory of Semi-Localized Recombination

P41

MKAM TCHOUOBIAP, SERGES ERIC C. M. Ngabireng and T. C. Kofane Effect of Quantum Fluctuations and Deformability Parameter on Structural Phase Transitions for Ferroelectric Materials with Deformable Double-well Potentials

P42

MUZIKANTE Inta, E.Fonavs, B.Stiller, L.Brehmer Photoinduced processes in ordered organic polar thin films

P43

PIELICHOWSKI Jan, Dariusz Bogdal, Monika Bednarz, François Kajzar, Jacek Niziol, Pawel Armatys, Properties of diazocarbazole derivatives for novel photorefractive materials

P44

RAU Ileana, Jacek Niziol, Francois Kajzar, Giovanna Brusatin, Gioia della Giustina, Massimo Guglielmi, Roberto Centore, Milko E. van der Boom NOVEL SOL-GEL SYSTEMS FOR QUADRATIC NONLINEAR OPTICS

P45

SHEYKH SHOAIE IRAN, Oszra Farsi, THE ELECTRONIC PROPERIES FOR SOME SCHIFF BASE COMPOUNDS

P46

SWIATEK Josef, ELECTRICAL PROPERTIES OF THIN FILMS OF 1,4-cis-POLYBUTADIENE DOPED SiC

P47

TKACZYK Stanislaw Wieslaw, CHARGE CARRIER TRANSPORT IN P-SEXIPHENYL THIN FILMS

P48

VALA Martin, Martin Weiter, Gabriela Rajtrova,Stanislav Nešpùrek, Petr Toman, Juliusz Sworakowski, Photochromic properties of spiropyranes in polymeric p-conjugated matrices

P49

ZIANI NOSSAIR, A.MOKEDDEM, L.HEIRECHE, M.BELHADJI, Activation energy and conductivity study of the Ge-Te-Sb alloys

P50

Benoit Brousse, Bernard Ratier and André Moliton, A New Encapsulation Concept for Small Organic Molecule Based Solar Cells

Wednesday, July 13, 2005 – Session E: Multi-functional materials for advance electronics Chairman: Kirova N. E 083 E 090

08:30 MOLITON André, Ion beam’s contribution to organic optoelectronics/electronics. [email protected] (invited) 09:00 N. S. SARICIFTCI (plenary invited), Optoelectronic Devices Based on Fullerenes: present state and future prospects

10:00 -Coffee break E 103 E 110 E 113 E 115 E 121

10:30 BAESSLER Heinz, Vladimir I. Arkhipov, Charge carrier transport in neat and doped random random organic semiconductors. [email protected] (invited) 11:00 MENON 11:30 ARLAUSKAS Kestutis, Bimolecular charge carrier recombination in organic polymer structures. [email protected] 11:50 Wai Kin Chan, Ka Yan Kitty Man, Kai Wing Cheng, Chui Wan Tse, Aleksandra B. Djurisic, Fabrication of Photovoltaic Devices by Layer-by-Layer Polyelectrolyte Deposition Method 12:10 GEFFROY Bernard, Noëlla Lemaître, Christine Denis, Pascal Maisse, Paul Raimond, Bright white organic light-emitting diode with dual doped blue and yellow-orange emitting layers, [email protected] (invited)

12:30-15:30 BREAK -LUNCH 15:30 Coffee break Session F: Multi-functional materials for advance electronics Chairman: Geffroy B. F 160 F 163 F 170 F 173 F 175

F 181 F 183

16:00 SHIROTA Y, [email protected] (invited) 16:30 SCHRADER Sigurd (invited) Valence Electronic Structure and Trap States in OFET Materials 17:00 KIROVA N., Understanding excitons in optical active polymers (invited) 17:30 ARKHIPOV V.I., E.V.Emelianova, P.Heremans, H.Bässler, Carrier Mobility in Doped Disordered Organic Semiconductors [email protected] 17:50 CRAVINO A., H. Neugebauer, A. Petr, P. J. Skabara, H. J. Spencerc, J. J. W. McDouall, L. Dunsch, N. S. Sariciftci, On the properties of Polyethylenedithiathiophene (PEDTT) - The Sulphur containing analogue of Polyethylenedioxythiophene (PEDOT)" 18:10 NOVIKOV Sergey, G.G. Malliaras, Energetic disorder at the interface between disordered organic material and metal electrode [email protected] 18:30 PANDEY K. Ajay, K. N. N .Unni, H. Wang, C. C. Oey, A. B. Djurišic, M. H. Xie, Y. H. Leung, K. K. Y. Man, W. K. Chan,

F 185 F191

F 193

P. C. Chui, J. M. Nunzi, Improved performance of organic nanocomposite solar cells with reverse biased annealing 18:50 PFLEGER Jiri, Q. T. Vu, W. Plieth, Polymer Bulk Heterostructures for Charge Carrier Photogeneration, [email protected] (invited) 19:10 SIMON Jean-Jacques, Ph. Torchio, F. Monestier, M. Cathelinaud and L. Escoubas, Demonstration of a software for automatic optimization of the electromagnetic field in organic solar cells, [email protected] 19:30 ULANSKI Jacek, Organic FETs obtained by zone-casting technique [email protected] (invited).

Friday, July 15, 2005 – Session G: Opticaly switchable materials Chairman: Kajzar F. G 083

G 090

G 092

G 094

08:30 MAKOWSKA-JANUSIK Malgorzata, Environmental effect on the NLO molecular response in guest-host materials. [email protected] (invited) 09:00 APOSTOLUK Aleksandra, Licinio Rocha, Céline FioriniDebuisschert, Carole Sentein, Paul Raimond, Alessandro FraleoniMorgera, Leonardo Setti, Jean-Michel Nunzi, Organic Semiconducting Polymer Devices based on Oriented Polymer Thin Films. 09:20 DABIRIAN Reza, Yann-Vai Kervennic, Jos M.Thijssen, Herre S.J. van der Zant, Daniel Vanmaekelbergh, Cornelis A. van Walree, Leonardus W. Jenneskens, Individual molecule orbital mediated transport through sigma-pi-sigma systems in an atomically controlled three-terminal device. 09:40 RIVERA Ernesto, C. Becerril, R. Salazar, M.P. Carreón-Castro, O. Morales-Saavedra, Langmuir-Blodgett Films and Non-Linear Optical Properties of Amphiphilic Azobenzenes bearing Poly (ethylene glycol) Segments. [email protected]

10:00 -Coffee break G 103 Fonavs G 105

10:30 RUTKIS Martins, A. Vembris, V. Zauls, A. Tokmakov, E. Non-linear optical properties of polymer systems with the poled indandione derivatives as a chromophores”, [email protected] 10:50 MANDOWSKI Arkadiusz, E. Mandowska, Determination of the Distribution of Activation Energies from Thermoluminescence Using Monte Carlo Method, [email protected]

11:30 Closing ceremony

A 083

ON THE MECHANISMS OF LIGHT-INDUCED OPTICAL ANISOTROPY IN ORGANIC AND BIOORGANIC SYSTEMS. Andrzej Miniewicz, Institute of Physical and Theoretical Chemistry, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland e-mail: [email protected] Light-induced optical anisotropy is a fundamental phenomenon occurring in many organic optical materials, like photochromic and photorefractive polymers, lowmolecular mass liquid crystals and polymer liquid crystals, as well as, in bioorganic systems like bacteriorhodopsin (bR). Bistable photochromic molecules embedded in various matrices are responsible for photoinduced anisotropy in photochromic materials but also in bacteriorhodopsin. However, mechanisms leading to an appearance of substantial light induced birefringence or dichroism are different. In liquid crystals and photorefractive polymers a initiated by light molecular reorientation plays a dominant role. In any case, we deal with near resonance optical linear or nonlinear processes mediated frequently by environment. The characteristic features underlying these phenomena as studied by wave-mixing techniques will be presented and discussed. Comparative studies of diffraction grating inscription (continuos and pulsed laser light illumination) in different types of materials allowed us to observe differences and similarities between various processes. Some of materials are particularly suitable for permanent optical data storage, some for rewritable holographic optical storage systems and some for dynamic optical memories and processors. Time scale and magnitude of anisotropy is directly related to the particular mechanism of photon-matter interaction and will be illustrated on many examples. Optical properties of studied materials make them attractive for dynamic holographic applications e.g. holographic interferometry, vibration and flow analysis, imaging through distorting media, holographic optical tweezers, three-dimensional displays, light amplifiers and converters.

A 090 HIGH SPEED LIGHT MODULATION PROPERTIES OF BIODEGRADABLE PIEZOELECTRIC POLYMERS

A 092 DEPENDENCE OF LUMINESCENCE PROPERTIES ON PREPARATION CONDITIONS OF EPOXY RESIN MODIFIED BY CARBAZOLE DERIVATIVE E. Mandowska1, A. Mandowski1, J. Świątek1, W. Mazela2, P. Czub2, J. Pielichowski2 1

Institute of Physics, Jan Długosz University, ul. Armii Krajowej 13/15, 42-200 Częstochowa, Poland; e-mail: [email protected] 2 Department of Chemistry and Technology of Polymers, Cracow University of Technology, ul. Warszawska 24, 31-155 Kraków

Carbazole is an organic molecule that has shown potential for applications in construction of polymer light emitting devices (PLEDs). Polymers with this molecule have strong absorption in ultraviolet spectral region and blue light emission. However, most of these materials suffer from inappropriate mechanical properties as well as its usually complex synthesis. In our study epoxy resin was used as a base material. Epoxy resins have many different applications in coatings, adhesives, laminates and probably it will be possible to used them in construction of PLEDs. The synthesis of this new promising material is simple. Thin film samples were prepared from solution by spin – coating method.

To obtain the best luminescence properties we analysed the influence of various factors including different solvents used during preparation, different concentration of carbazole group and curing agent. The dependence of the absorption and photoluminescence (PL) spectra of RxEPK on these factors was determind. Typical results of PL optimization due to carbazole group content in completely cross linked polimer are shown in Fig. 1. The best PL efficiency was obtained for x=5%.

3500 351

367

3000 PL intensity (a.u.)

The epoxy resin with carbazolyl groups was made by adding glycydyl derivative of carbazole – 9-(2,3epoxypropyl)carbazole (EPK) to epoxy resin (R). This homogenous composition was crosslinked in the next step. In curing process we obtained a homogenous polymer with the carbazolyl group chemically bonded to the resin (RxEPK, where x is the weight content of the carbazole group). This polymer has excellent mechanical properties, high thermal stability and good chemical resistance.

2500 2000 1500 1000

RxEPK x=0% x=0.1% x=1% x=5% x=10% x=15%

500 0 300

350 400 450 Wavelength (nm)

500

Fig. 1 Photoluminescence of thin film RxEPK excited by 286 nm light at room temperature. Two pronounced maxima of the emission spectrum are shown.

A 094 SPECTRAL AND ELECTRICAL INVESTIGATION OF THE SPIN-LADDER CANDIDATE (N-C2H5-PZ)(TCNQ)2 A. Łapiński1, M. Golub1, V. A. Starodub2 1

Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17, 60-179 Poznań, Poland, [email protected] 2 Departament of Chemistry, Kharkov National Karabin University, 61077 Kharkov, Ukraine, [email protected]

Charge transfer salts of the anion radical TCNQ- (tetracyanoquinodimethane) exhibit a wide variety of electrical and magnetic properties which are strongly dependent on the cation. In most of these salts the TCNQ molecules stack face-to-face and form linear chains with significant overlap of π-molecular orbitals and high density of radical electrons. Recently, in search for interesting materials the new charge transfer salt (N-C2H5-Pz)(TCNQ)2 with extraordinary crystal structure, was synthesized. In this work, we study the electrical transport, magnetic, and optical properties of (N-C2H5-Pz)(TCNQ)2. The vibrational and electronic spectra of the crystalline samples were analyzed and assignment of the vibrational features, base on the theoretical calculations made by us, was proposed. The level of calculations used for (N-C2H5-Pz)+ and TCNQ0 molecules was DFT(B3LYP) with the 6-311++G(d,p) basis set. A systematic analysis of the spectra allowed us to obtain important information about the electronic and vibrational structure. Moreover, the temperature dependence of the vibrational spectra, the ESR absorption spectra, the static magnetic susceptibility, the anisotropy of electrical conductivity, and the thermopower measurements of the (NC2H5-Pz)(TCNQ)2 were measured and discussed. The polarized reflectance and transmittance spectra of single crystals of this salt were recorded in the range 600-6500 cm-1, down to 4.2 K. Additionally, the optical absorption spectra, the Raman spectra, and diffuse reflectance spectra of the powdered salt dispersed in KBr pellets were measured. In order to analyze the plasma-edge-like dispersion in reflectance spectra of (N-C2H5-Pz)(TCNQ)2 the Drude-Lorentz dielectric function was used. Base on our investigations we propose that (N-C2H5-Pz)(TCNQ)2 salt is the fully organic structural spin-ladder candidate. Such materials have attracted considerable interest as intermediaries between one-dimensional (1D) chains and twodimensional (2D) square lattices. Moreover, additional interest in such systems has arisen from theoretical studies of the t-J model, which find that hole-doped spin ladders can support superconductivity.

A 103

MICROHOLOGRAPHIC DATA STORAGE Hans Joachim Eichler Optisches Institut, Technische Universitaet, 10623 Berlin, Germany

Holographic data storage has been suggested more than 30 years ago. It was expected that volume holograms written into photosensitive media allow high storage capacities of 1 bit per cube of recording wavelength. The volume of a compact disc with 12 cm diameter thus offers a capacity of 10 Terabytes. In conventional holographic storage systems, Megabit data pages are recorded as Fourier transform holograms so that the information about each single bit is spread over the entire hologram. Dust and scratches on the surface of the storage medium decrease to some degree the signal-to-noise ratio for an entire data page but do not lead to a total loss of some bits. This has been considered to be an advantage of holographic storage but it turned out that the influence of tiny surface imperfections are reduced also in bitby-bit storage on a CD or DVD by means of a protective layer and a strongly focussed read-beam. Another advantage of page oriented holographic storage could be highly parallel data transfer so that Gigabit/s read-out rates are feasible. Conventional, page-oriented holographic storage requires a special setup starting with a spatial light modulator converting the incoming data stream into arrays of dark and bright pixels each representing a bit. Coherent light from a laser illuminates this page composer and interferes with a reference beam from the same laser in the photosensitive medium e.g. a 1cm cube of a photorefractive crystal or polymer disc with 1mm thickness. The interference pattern is stored there usually as a phase hologram. A sequence of data pages is stored by using different angles between the signal and reference beam in the crystal or by addressing different positions on a rotating disc. For read-out of any of the stored data pages, the corresponding hologram is addressed by the reference alone which is diffracted generating a faithful replica of the signal beam. The reconstructed bit page is reconverted into an electric data stream with a photodetector matrix. Based on these principles, complete holographic storage systems have been successfully built /1/ but these devices have not found yet widespread applications because the technology has to be developped further towards miniaturization. Microholographic data storage /2/ has been suggested therefore to combine the holographic potential of high capacity with the mature compact disc and DVD technology. A microholographic write-system uses two counterpropagating strongly focussed laser beams generating a microscopic reflection grating in a photopolymer disc. The two beams can be generated by two frequency locked DVD-type focussed laser sources or by only one laser and a retroreflective mirror on the opposite side of the disc. The grating planes are perpendicular to the beam direction and have submicron diameter /3/. The grating period of about 130nm is given by half the wavelength (e.g. 400nm) of the write laser inside the polymer (refractive index e.g. 1.5) which means that a material resolution of 7500 lines/mm is required. The axial extension of the grating may be in the order of 5µm. These nanostructured, reflective microgratings are

read out by a single laser beam so that the pickup may be similar as in a DVD-drive and downward compatible. The microgratings can be written along a spiral path into a photopolymer disc with an aerial density close to the pit density on a compact disc. Several layers of microgratings have been written parallel to the photopolymer surface to increase the storage capacity beyond the DVD-limit. Further increase of the storage capacity is possible by writing overlapping gratings with different periods using several different wavelengths. Such superimposed gratings are read out selectively using again the appropriate wavelength. Combined multilayer storage and wavelength multiplexing promise storage densities approaching the Terabyte range. Photopolymers or other materials for microholographic data storage are investigated from the pool of materials already tested and used for conventional holography /1/. However, microholographic storage requires especially high resolution and the materials have to be optimized for sufficient holographic reflectivity and simultaneously small lensing effects disturbing the generation and read-out of the microgratings. The construction and investigation of microholographic write and read devices as well as material selection is under investigation by different groups worldwide and will be overviewed References /1/ B.Hesselink, S.Orlov, M.Bashaw, Proc. IEEE 92 (2004) 1231 /2/ H.J.Eichler, P.Kuemmel, S.Orlic, A.Wappelt, IEEE J. Select. Topics Quant. 4 (1998) 840 /3/ S. Orlic, E. Dietz, S. Frohmann, Ch. Müller, H. J. Eichler,Proc. SPIE vol. 5521, p. 149-160, 2004

A 110 SUB-5-FS REAL-TIME SPECTROSCOPY TO CLARIFY THE MECHANISM OF ULTRAFAST OPTICAL NONLINEARITY IN A CONJUGATED POLYMER Takayoshi Kobayashi, Yoshiharu Yuasa, and Mitsuhiro Ikuta 1

Department of physics, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyoku, Tokyo, 113-0033, Japan Tel.: +81 3 5841 4227 FAX: +81 3 5841 4165 E-mail: [email protected]

Abstract To clarify the mechanism of ultrafast optical nonlinearity in polymer especially polydiacetylene real-time measurement of molecular vibration, which can provide information of time-resolved structural changes associated with huge electronic spectral change, was performed. Molecular vibration of several modes in blue-phase polydiacetylene-3-butoxycarbonylmethylurethane (PDA-3BCMU) was time resolved by 5-fs pump-probe measurement. Change during the very fast relaxation process was time-resolved with 1-fs step measurement of the transition in the polymer and it was found to take place with 60 fs time constant from the butatriene-like structure to the acetylene-like structure for the first time. Separation of the contributions of the vibrational wavepackets in the ground state and that in the excited state in the signal were performed. The C=C stretching mode in the ground state starts to oscillate π-out-of-phase with the C≡C stretching mode. The structure of PDA-3BCMU in the geometrically relaxed state is not pure butatriene-type but more like acetylene-type. The frequencies of C=C and C≡C stretching modes there were determined by singular value decomposition method to be 1472 ± 6 cm-1 and 2092 ± 6 cm-1, respectively. The corresponding frequencies in the ground state were calculated as 1463 and 2083 cm-1. Each of the frequencies in the geometrically relaxed 21Ag state is higher by about 10 cm-1 than each of the ground state. It means that the frequencies of both modes were increased in the geometrically relaxed state. The wavepacket of C=C stretching mode in the ground state was found to start at first to oscillate to the opposite direction to that of C≡C stretching mode. Also the vibration of C≡C stretching mode in the geometrically relaxed 21Ag state was observed as well as C=C stretching mode even after the free exciton state is decayed to the geometrically relaxed state within 100 fs.

A 113 Influence of the structure of azo dyes on cis- trans photoisomerization kinetics in solution, polymer matrix and LB films. A.Vembris1,2, E.Laizāne1, A.Tokmakov1, L.Gerca1, I.Muzikante1,2, E.Markava3, D.Gustiņa3 1 Institute of Solid State Physics, University of Latvia, Ķengaraga Str. 8, Riga LV-1063 2

Institute of Physical Energetic, Aizkraukles Str. 21, Riga LV 1006 3

Latvian Institute of Organic Synthesis, Aizkraukles Str 21, Riga LV 1006

Azobenzene molecules have reversible optical switching effect between two metastable states- trans- and cis- isomers with different optical properties. That effect can be used in future photonic devices. Progress in that field of material science is highly dependant on synthesis and studies of the new chromophores with enhanced photoswitching potential. In this work we are presenting our studies of the isomerization kinetics of the four new polar azobenzene derivatives with different functional groups (Figure 1). The studies were carried out in chloroform solution, in the polymer matrix as host-guest system with polimethylmethacrylate and Langmuir – Blodgett (LB) multilayers. First of all compounds were tested in chloroform solution (1*10-4 mol/l) to investigate functional group effect on the spectral parameters, then on trans- cis and cis – trans photoisomerization kinetics and absorbance alternation amplitude. 1. Figure Azobenzene derivatives with Next step was to study photoswitching properties functional groups of these azobenzene molecules in thin films. A host-guest polymer system of 1wt% azobenzene in PMMA was prepared on quartz glass substrate by solution casting method. In case of the A-45 it is possible to produce LB multilayer Y-type film. The photoswitching properties of the 19 monolayers LB sample on fused quartz have been investigated.

A 115

PHOTOCHROMIC PROPERTIES OF THE POLYMER FILMS CONTAINING SINGLE AND DUAL CHROMOPHORE SYSTEM S. Kucharski*, E. Ortyl, R. Janik Institute of Organic and Polymer Technology, Wrocław University of Technology, 50-370, Wrocław (Poland) Series of polymers of the polyurethane type were synthesized which, in the next step, were modified chemically by coupling reaction with diazonium salts. The diazonium salts were derivatives of sulfonamides containing heterocyclic rings such as: thiazole, pyrimidine and dimethylpyrimidine. Degree of modification expressed by the coupling ratio reached up to 40 %. The materials so obtained were used to form transparent films on glass substrate and showed reversible change of spectral properties as a result of trans-cis isomerization of the diazo group. The maximum absorption band of the films lied at ca. 440 nm. The change of the refractive index under illumination, measured in ellipsometric arrangement, showed both reversibility of the process and promising prospects to use these materials in holographic tests. The action of laser green light (λ=532 nm) applied in two wave mixing experiments produced diffraction grating in the materials both of the transient character, disappearing within few seconds if illumination was carried out in seconds intervals, and of stable character when the films were illuminated for 10-30 min. The formation of surface relief grating in the latter case was documented by atomic force microscopy. The dual system of chromophores was composed of the photochromic polymer and spiropyran deposited by spin-coating using solution of the two components. The film was illuminated with UV lamp to induce formation of open form (merocyanine) from spiropyran. Merocyanine absorbed strongly at ca.580 nm enhancing absorption range of the system. The action of green light caused reverse photoreaction from merocyanine to spiropyran and at the same time the trans-cis isomerization of the diazo containing polymers. The presence of two chromophoric species enhanced the photochromic properties of the materials in question. H3C

H3C CH3

CH3 O

O N

N

+

O

N

-

CH3

O

CH3 +

N O

spiropyran

O

-

merocyanine

References: Ortyl E.,Janik R., Kucharski S., „Methacrylate polymers with photochromic side chains containing heterocyclic sulfonamide substituted azobenzene”Eur. Polymer. J., 2002, 38, 1871-79; Ortyl E,. Kucharski S., „Refractive Index Modulation in the Polyurethane Films Containing Diazo Sulfonamide Chromophores”, Thin Solid Films (in press); Ortyl E., Thesis, Wrocław University of Technology, 2005

A 121 VISIBLE AND NEAR-INFRARED LIGHT AMPLIFICATION AND LASING IN LUMINESCENT POLYMER MICROSTRUCTURES

Takeyuki Kobayashi and Werner J. Blau Materials Ireland Polymer Research Centre, Department of Physics, Trinity College Dublin, Dublin 2, IRELAND Email: [email protected]; Tel: +353 1 608 1324; Fax: +353 1 671 1759

In the past decade, polymers with extremely low absorption loss values have been designed and synthesized for the fabrication of passive waveguides for use in short distance optical networks. Some polymers have values of less than 0.01 dB/cm at 520, 840, and 1310 nm. Therefore, light amplifiers and lasers operating at these communication wavelengths may find applications in polymer optical fibre-based local area networks and optical interconnects. We have demonstrated photopumped optical gain and laser emission at around 500 nm and 800 nm in high-Q polymer cavities with different structures. For example, polymer microrings 200 micron in diameter were fabricated with an inert polymer doped with 2-(6-(4-dimethylaminophenyl)-2,4-neopentylene-1,3,5-hexatrienyl)-3-methylbenzothiazolium perchlorat and were shown to lase at 840 nm under nanosecond photopumping at 532 nm. From the input-output characteristics, the threshold for lasing was found to be 1.7 mJ/cm2. When a blue-green emitting dye, 1,4-Bis[2-[4-[N,N-di(ptolyl)amino]phenyl]vinyl]benzene, was used, the microring devices exhibited laser emission at around 500 nm under nanosecond pumping at 355 nm. We also demonstrated distributed feedback lasing tunable between 840 and 870 nm from dyedoped polymer waveguides 2 mm in length. Furthermore, gain spectroscopy in the nanosecond region was performed by means of the variable stripe length method. Measurements on polymer thin films doped with these dyes revealed large gains of up to 80 cm-1, depending on host polymers and photopumping conditions. We have a prospect that polymer lasers and amplifiers operating in the visible and nearinfrared can be extremely useful for use in polymer-based local area networks where a large number of devices may need to be introduced. Our results should open the way for the development of such devices.

B 160 PHOTONIC MATERIALS BASED ON DNA [DEOXYRIBONUCLEIC ACID] James Grotea, Emily Heckmanb, Josh Hagenc, Perry Yaneyb, Guru Subramanyamb Andrew Stecklc, Darnell Diggsa, John Zettsa, Noaya Ogatad, Paras Prasade and Frank Hopkinsa a

Air Force Research Laboratory, Wright-Patterson Air Force Base, OH 45433-7707 USA b University of Dayton, Dayton, OH 45469 USA c University of Cincinnati, Cincinnati, OH 45221-0012 USA d Chitose Institute of Science and Technology, Chitose, Hokkaido 066-8655 Japan e State University of New York at Buffalo, Buffalo, New York 14260 USA

Deoxyribonucleic acid (DNA) based materials show promise for use in photonic applications. Preliminary characterization studies indicate that DNA has excellent optical and electromagnetic properties, such as low optical loss, high temperature stability and low resistivity. The DNA being used for this investigation is extracted from salmon roe and milt sacs, waste products of Japan’s fishing industry. It is purified at the Chitose Institute of Science and Technology (CIST). The molecular weight of the purified DNA supplied from CIST measures MW = 6.5x106 - 8.0x106, the purity measured assay = 96%, and the protein content typically measures 2%. The DNA is precipitated with a surfactant, cetyltrimethl-ammonium (CTMA), through an ion exchange reaction that replaced the sodium cation of the DNA. The resulting DNA-CTMA complex is water insoluble and more mechanically stable due to the long alkyl chain of the CTMA. This complex is soluble in ethanol, methanol, butanol or a chloroform/alcohol blend, making it more compatible with standard optical waveguide device fabrication techniques. The optical transmission spectrum of an un-doped DNA-CTMA film is shown in Fig. 1. The optical losses at optical link and telecommunication wavelengths are quite low, ~0.1 dB/cm at λ = 800 nm, ~0.7 dB/cm at λ = 980 nm and 1550 nm and ~0.20 dB/cm at λ = 1300 nm. For waveguide applications, total losses less than 1 dB/cm are typically desired. DNA-CTMA should meet this criterion. The background transmission in Fig. 1 is approximate and is estimated to be within 0.2 dB/cm of the actual value. The index of refraction of un-doped DNA-CTMA, see Fig. 2, is lower than the index of most common polymer materials. As can be seen in Fig. 3, the measured resistivity of DNA-CTMA, as a function of temperature, is 10 – 102 times lower than most polymer materials commonly used for optical waveguide device applications. Addition of various nonlinear optical materials into DNA-CTMA suggests property enhancements compared with using other polymer materials as hosts.

1015 Resistivity (Ω-cm)

PMMA 1013 1011

DNA

109 40

Figure 1

Figure 2

60 80 100 Temperature (°C)

Figure

3 1. 2. 3. 4.

L. Wang, J. Yoshida, N. Ogata, S. Sasaki, and T. Kajiyama, Chem. Mat., 13(4), pp. 1273-1281, 2001 G. Zhang, L. Wang, J. Yoshida and N. Ogata, SPIE Proc., 4580, pp. 337-346, 2001 J. Grote, N. Ogata, D. Diggs and F. Hopkins, SPIE Proc., 4991, pp. 621-625, 2003 J. Grote, J. Zetts, R. Nelson, D. Diggs, F. Hopkins, M. Stone, P. Yaney, E. Heckman, C. Zhang, W. Steier, M-C. Oh, H. Fetterman, A. Jen, L. Dalton, E. Taylor, J. Winter, A. Sanchez, D. Craig, N. Ogata, J. Hagen and M. Curley, J. Phys. Chem. B, 108(25), pp. 8584-8591, 2004

B 163 CARBAZOLE BASED PHOTOREFRACTIVE POLYMERIC MATERIALS Dariusz Bogdal

Department of Chemistry and Technology of Polymers Cracow University of Technology Warszawska 24, 31-155 Krakow, Poland e-mail: [email protected]

The

photorefractive

materials

are

multifunctional

materials

which

combine

photoconductivity (generation and transport of charge carriers under irradiation) and nonlinear optical (NLO) properties (electro-optic (EO) response). The photorefractive effect arises from a light-induced generation and migration of charges in material, which give rise to internal space charge fields. A change in refractive index is produced by these electric fields through the linear electro-optic effect. To be photorefractive, a material must be photoconductive as well as electro-optic. Some materials demonstrating a photorefractive effect contain carbazole functionality. An overview of such materials will be given:

•

Carbazole and type of carbazole based polymers

•

Poly(N-vinylcarbazole) (PVK) and its composite materials

•

Side-chain and main-chain fully functionalize carbazole polymers

•

Compounds with carbazole moiety in composite materials

•

Carbazole polymers with alternative backbone

•

Conclusions

B 165 DESIGN AND SYNTHESIS OF NOVEL [60] FULLERENE DERIVATIVES FOR SELFASSEMBLY Gabriela ALDEA*1,2, Gabrielle-Charlotte CHITANU1, Bogdan C. SIMIONESCU1, Jack COUSSEAU2, Sylvie DABOS-SEIGNON2, Jean-Michel NUNZI2 1

„Petru Poni” Institute of Macromolecular Chemistry Iasi, Romanian Academy, Aleea Grigore Ghica

Voda 41A, 700487, Iasi, Romania, [email protected] 2

Université d’Angers, ERT N°15 Cellules Solaires Photovoltaïques Plastiques, Laboratoire POMA,

UMR CNRS No 6136, France Self-assembly is an area of vigorous research activity that has strongly impacted several facets of Materials Science. It is motivated by the anticipation that a careful design of the precursors will direct the process of molecular organization in order to build multi-functional structures. In response to growing demand for environmentally friendly electronic devices, we designed, synthesized and characterized new highly water-soluble pendant-fullerene copolymers based on maleic anhydride. These water soluble C60 fullerene derivatives can self-organize from an aqueous solution into multilayer films for potential applications in opto-electronics.

B 171 ELABORATION OF CONDUCTIVE POLYMER COMPOSITES : OVERVIEW G. Boiteux1 , M. Chouiki1, J. Davenas1, , C. Boullanger1, G. Seytre1, P. Cassagnau1, J. Ulanski2, A. Mierczynska2, Y.V. Mamunya3, P. Pissis4, and J.K. Jeszka2,5 1

Laboratoire des Matériaux Polymères et Biomatériaux, UCB-Lyon 1, Villeurbanne, France 2

3

Department of Molecular Physics, TUL, £ódz, Poland

Institut of Macromolecular Chemistry, Ukraine Academy of Sciences, Kiev, Ukraine 4

5

Department of Physics, NTUA, Athens, Greece

Centre of Molecular and Macromolecular Studies, PAS, Lodz, Poland. * E-mail : Gisele. [email protected]

Conductive polymer composites are very interesting materials based on an insulating matrix filled with conductive fillers above a critical volume fraction (percolation threshold) for which the materials become conductive. It is common to use carbon black or metallic particles and more recently “synthetic metals” introduced by different methods to the polymer matrix (thermoset or thermoplastic) [1,2]. Generally the percolation threshold depends on several factors like the types and morphology of polymers and fillers used, preparation and conditions. In the present work, we describe two methods of processing of such systems. New environmentally friendly coatings based on conductive latex based on Polyurethane– Polypyrrole core-shell particles were obtained by mixing with insulating polymer latex [3] and they show promising conduction properties. The films by casting of the mixture of the latex show the percolation threshold around 4%, with improved mechanical properties compared to polypyrrole films. Investigations of temperature dependence of conductivity in a wide temperature range has allowed us to determine the charge carrier transport mechanism. In more traditional way we have prepared conductive composites by melt mixing polyethylene and different polyethylene-polyoxymethylene blends with silver or iron filler. Different processing machines were used as Haake Rheocord, Scamia calander or DSM mini mono or twin screw extruder. It was found that the process of blending in the latter case yields better results, as the mixtures are easier to prepare and much more homogeneous. Such samples present quite low percolation threshold around 22% for Ag and 28% for Fe. The percolation threshold is much lower in biphasic systems. The main interest of such extrinsic conductive materials is that additionally to their conductive properties, they can present also the Positive Temperature Coefficient (PTC) effect [4,5,6] upon heating, it means very strong resistivity “jump” at the so-called commutation temperature Tc. Such disruptor is very efficient due to 8 decades increase of the resistivity for different temperatures according the system under studies. It will be shown that this effect greatly depend on the morphology of the matrix, on the state of dispersion of the silver and iron particles and of the thermal expansion coefficient of the matrix. Such extended studies show the interest of such adaptative or so-called smart materials. It will be also presented a sintering method to prepare conductive polyethylene/single walled carbon nanotubes composites Aknowledgements : The authors are very grateful for the financial support of MRES for M. Chouiki, of the ANRT and Areva company for C. Boullanger, of NATO for the grant of Dr. Y. E. Mamunya and KBN for A. Mierczynska [1] F. M. Huijs, F.F. Vercauteren, B. De Ruiter, D. Kalicharan, G. Hadziioannou, Synthetic Metals (1999), 102(1-3), 1151-1152. [2] Strumpler, R.; Glatz-Reichenbach, Journal of Electroceramics (1999), 3(4), 329-346 [3] J. Niziol , G. Boiteux, M. Chouiki, J. Ulanski, Proceedings of International Conference on Science and Technology of Synthetic Metals, Shanghai (China), 29/06-05/07 2002 [4] M. Narkis, J. Yacubowicz, A. Vaxman, A. Marmur, Polym. Eng. Sci., 26, 139-143 (1986). [5] G. Boiteux, J. Fournier, D. Issotier, G. Seytre, G. Marichy, Synthetic Metals, 102 (1999) 1234-1235 [6] Y.P. Mamunya, Y.V. Muzychenko, P. Pissis, E.V. Lebedev, M.I. Shut, Polymer Engineering and Science, 42 (1) (2002) 90-100

B 173 MALEIC ANHYDRIDE COPOLYMERS AS MULTI-FUNCTIONAL MATERIALS FOR ENVIRONMENT PROTECTION Gabrielle Charlotte CHITANU “Petru Poni” Institute of Macromolecular Chemistry, Roumanian Academy Aleea Grigore Ghica Voda 41A, 700487, Iasi, Roumania; [email protected] The multi-functional materials are one of the most recent topics, which were successfully developed. The properties of maleic copolymers as multi-functional materials were not yet developed, but it can be easily seen that they are particularly suitable for this purpose. Their chemical structure can be tailored either by the appropriate choice of the comonomer (hydrophilic or hydrophobic) or by the chemical reaction with suitable low molecular compounds bearing different functions: charged groups (which cause them to behave as polyelectrolytes), dyes or chromophores, bioactive molecules, LC moieties, and other. Moreover they can be obtained from easily accessible commercial monomers which are relatively cheap, by radical copolymerization in organic solvents using common initiators. The comonomer can be N-vinylpyrrolidone (NVP), vinyl acetate (VA), methyl methacrylate (MMA), or styrene (St), given in the order of increasing hydrophobic character. Our contribution discusses a series of results that evidence the favorable effect of maleic polyelectrolytes in different fields in which a protective action of the environment is attained: i) the exploitation of geothermal water, which is a cleaner alternative source of energy; ii) the reduction of chromium load of effluents from tanning plants; iii) the improvement or preservation of the structure of agricultural soils and iv) the substitution of phosphates in detergents. We present also recent results in some advanced topics which can lead to environmentally friendly products or processes: • layer-by-layer deposition from maleic polyelectrolytes and dyes; • synthesis of new maleic copolymers derivatives containing dyes or chromophores for electronic or optoelectronic applications; • maleic polyelectrolytes as crystallization modulators; • synthesis of new maleic anhydride copolymers with bulky/hydrophobic comonomers such as vinylnaphthalene, N-vinylcarbazole, N-vinylcaprolactame.

References

[1] Commoner B. The Closing Circle. Nature, Man and Technology; Alfred A. Knopf: New York, 1972 (Romanian Edition, Editura Politica: Bucharest, 1980). [2] Scott G. Polymer Degrad. Stab. 2000, 68, 1 [3] Scott G. Polymers and the Environment; Royal Society of Chemistry: Cambridge, 1999. Acknowledgement: The financial support of MATNANTECH Program of the Roumanian Ministry of Education and Research, project no. C111/2002-2005 and C138/2003-2005 is gratefully acknowledged.

B 175 NEW COPOLYMERS BASED ON POLY(3-ALKYLTHIOPHENE) AND FULLERENE FOR PHOTOVOLTAIC APPLICATIONS a

b

b

c

Roger C Hiorns* , Jocelyne Leroy , Rémi de Bettignies , Hugues Preudhomme , d

b

b

Hervé Martinez , Muriel Firon , Carole Sentein , Christine Dagron-Lartigau

a

a

LPCP, UMR 5067, Hélioparc Pau Pyrénées, 2 Av. P. Angot, 64053 Pau CEDEX 9, France DRT/LITEN/DSEN/GENEC/L2C, CEA Saclay, 91191 Gif sur Yvette Cedex France c LCABIE, UMR-CNRS 5034, Hélioparc Pau Pyrénées, 2 Av. P. Angot, 64053 Pau CEDEX 9, France LPCM, CNRS-UMR 5624, Hélioparc Pau Pyrénées, 2 Av. P. Angot, 64053 Pau CEDEX 9, France b

d

e-mail: [email protected] 1

Regioregular poly(3-alkylthiophene)s (P3AT) as p-type 'donor' polymers have attracted considerable interest for photovoltaic applications due to their relative stability and ease of mixing with widely used acceptors such as the methanofullerene derivative PCBM. Their ability to provide relatively high photovoltaic efficiencies rests heavily upon the nano-structure of the material, whether made from covalently bonded donor and acceptor molecules, or mixed in 2

composites. For a material to operate efficiently in a photovoltaic cell, it is expected that it should consist of donor and acceptor domains with interfaces not more than several tens of nanometers from centres of exciton formation and should exhibit a nano-structure which permits percolation of photo-charges to electrodes. It has been shown that highly repeated alternating copolymers may provide such structures, due to their tendency to give form dense domains of like segments 3 in regular, linear patterns. In an attempt to exploit the tendency of copolymers to self-organize, copolymers of P3BT or P3HT with fullerene were prepared, with the aimed for nano-structure schematised in Figure 1.

Initially, in order to understand the effect of the molecular weight of P3ATs on device efficiencies, a series of low polydispersity poly(3-butylthiophene)s (P3BT) and poly(3hexylthiophene)s (P3HT) were prepared with predetermined and varying molecular weights 4,5 using a chain-growth polymerisation in a methodology simplified from that shown elsewhere. Photovoltaic characterization of cells showed that the P3BT did not work well, most likely due to poor interdigitation of the side arm alkyl chains between overlapping polymer backbones. The P3HT cells, however, showed a considerable variation in photovoltaic properties with molecular weight. Then various routes to the chain-end modification of P3ATs were explored, 6 using those already known, and newly developed methods. These chain end modified copolymers were then reacted with fullerene using various routes to give regular, alternating copolymers, exampled by that shown in Figure 2. The preparation of these copolymers, their characterisation using NMR, SEC, and MALDITOF techniques along with AFM studies of their thin films will be presented and discussed.

Figure 2. Most probable structure of a copolymer formed from P3HT segments and C60.

The authors wish to thank the ADEME (Fr) for their financial support through the CSPVP program and contract number n°0105148. References 1. 1. McCullough RD, Adv. Mater. 10(2) (1998) 93. 2. 2. X Yang, J Loos, SC Veenstra, WJH Verhees, MM Wienk, JM Kroon, MAJ Michels and RAJ Janssen, Nano Letters, 5(4) (2005) 579. 3. 3. RC Hiorns and H Martinez, Synthetic Metals, 139 (2003) 463. 4. 4. A Yokoyama, R Miyakoshi, and T Yokozawa, Macromolecules 37 (2004) 1169. 5. 5. EE Sheina, J Liu, MC Iova, DW Laird and RD McCullough, Macromolecules 37 (2004) 3526. 6. 6. J Liu and RD McCullough, Macromolecules, 35 (2002) 9882.

B 181

CHARGE CARRIER TRANSPORT AND RECOMBINATION IN πCONJUGATED POLYMERS AND BULK HETEROJUNCTION SOLAR CELLS A. Pivrikas,1,2,* G. Juška,3 K. Arlauskas,3 A. J. Mozer,4 M. Scharber,5 N.S. Sariciftci,4 and R. Österbacka1 1

Åbo Akademi University, Department of Physics, Åbo, Finland Graduate School of Materials Research, Turku Universities, Finland. 3 Vilnius University, Department of Solid State Electronics, Vilnius, Lithuania. 4 Johannes Kepler University, Linz Institute for Organic Solar Cells, Linz, Austria. 5 Konarka Austria, Altenbergerstr. 69, Linz, Austria. 2

* Corresponding author: Phone: +358 2215 4607, Fax: +358 2215 4776, E-mail: [email protected] Charge transport parameters, e.g. carrier mobility, lifetime and concentration are important for the efficiency of solar cells. Usually these parameters are measured using Time-Of Flight (TOF) technique. We have developed complementary techniques such as CELIV (Carrier Extraction by Linearly Increasing Voltage) and CEPV (Carrier Extraction by Pulsed Voltage) to measure directly and independently the time dependence of the charge carrier mobility and concentration. Using TOF we show that the bimolecular charge carrier recombination in regiorandom poly (3-hexylthiophene) (RRaPHT) is of Langevin-type, as expected for low mobility materials. We have also measured the time dependence of the photogenerated charge carrier mobility and concentration independently using CELIV and CEPV techniques and found, that the decay of the charge carrier concentration can be well approximated with the time dependent Langevin-type bimolecular recombination coefficient (βL) obtained independently from the time dependent charge carrier mobility. We have also studied the charge carrier recombination in bulk heterojunction solar cells made from the mixture of regioregular poly(3-hexylthiophene) and 1-(3-methoxycarbonyl)propyl-1-phenyl-[6,6]-methanofullerene (PCBM) and found that the bimolecular charge carrier recombination is greatly reduced compared to the Langevin-type recombination (β/βL3.5% power conversion efficiency is reported. Furthermore, organic semiconductor based tunnel diodes, as well as organic field effect transistors (OFETs) will be reported with mobilities above 1cm2/Vs. Functionalized fullerene transistors such as photoactive, ambipolar photOFETs are used for the realization of simple circuits and high detectivity (>5 A/W) photosensor arrays and memory elements. Selected papers: 1)"Photoinduced Electron Transfer from a Conducting Polymer to Buckminsterfullerene" N. S. Sariciftci, L. Smilowitz, A. J. Heeger and F. Wudl, Science Vol. 258, 1474 (1992). 2) "Semiconducting Polymer - Buckminsterfullerene Heterojunctions: Diodes, Photodiodes and Photovoltaic Cells", N. S. Sariciftci, D. Braun, C. Zhang, V. Srdanov, A. J. Heeger and F. Wudl, Appl. Phys. Lett. Vol. 62 (6), 585 (1993). 3) "Tracing photoinduced electron transfer process from a conjugated polymer chain to a fullerene moiety in real time", C. J. Brabec, G. Zerza and N. S. Sariciftci, G. Cerullo, S. DeSilvestri, S. Luzatti, J. C. Hummelen Chem. Phys. Lett. Vol. 340, 232-236 (2001). 4) "2.5 % Efficient Organic Plastic Solar Cells", S.E. Shaheen, C.J. Brabec, N.S. Sariciftci, F. Padinger, T. Fromherz, J.C. Hummelen, Appl. Phys. Lett. Vol. 78: 841-843 (2001) 5) "Plastic Solar Cells" Christoph J. Brabec, N. Serdar Sariciftci, Jan Kees Hummelen, Advanced Functional Materials, Vol. 11 No: 1, pp.15-26 (2001). 6) "Double Cable Polymers for Fullerene Based Organic Optoelectronic Applications" Antonio Cravino and Niyazi Serdar Sariciftci, Journal of Materials Chemistry Special Issue on Functional Fullerene Materials, Vol. 12 (2002), 1931-1943 M. Prato (guest editor) . 7) “Hybrid Solar Cells based on Nanoparticles of CulnS2 in Organic Matrices” E. Arici, N.S. Sariciftci, D. Meissner Advanced Functional Materials (2003), Vol. 13, No.2, pp. 165-171 8) “Nonvolatile Organic Field-Effect Transistor Memory Element with a Polymeric Gate Electret” Th. B. Singh, N. Marjanovic, G. J. Matt, N. S. Sariciftci, R. Schwödiauer and S. Bauer Applied Physics Letters, Vol 85, No. 22, 5409 (2004). 9) “Fabrication and characterisation of solution processed methanofullerene based organic field effect transistors” Th. B. Singh,N. Marjanovic,P. Stadler, M. Auinger, G. J. Matt, S. Günes, N. S. Sariciftci, R. Schwoediauer, S. Bauer, Journal of Applied Physics, Vol 97 (2005) 83714.

E 103 CHARGE CARRIER TRANSPORT IN NEAT AND DOPED RANDOM RANDOM ORGANIC SEMICONDUCTORS Vladimir I.Arkhipov (a) and Heinz Baessler (b) (a) IMEC, Kapeldreef 75, B-3001 Heverlee-Leuven, Belgium (b) Insitute of Physical, Nuclear and Macromolecular Chemistry, Philipps University, Hans Meerweinstrasse, D-35032 Marburg, Germany The concept of charge carrier hopping in random organic semiconductors, e.g. molecular glasses, molecularly doped polymers, and conjugated polymers, will be reviewed briefly. Recent advances include (i) the experimental and theoretical verification of the negative field dependence of the charge carrier mobility at moderate electric fields, (ii) the assessment of polaron effects, (iii) the analysis of charge carrier trapping at neutral dopants, and (iv) charge transport in the presence of a localized homo- or heterocharge stored in the bulk of the sample. The latter phenomenon is relevant for the understanding of the performance of organic field effect transitors and of systems containing ionized dopants. They can be accounted for by considering the opposing effects of roughening the energy landscape due to stationary charges and the shift of the quasi Fermi-level.

E 113

BIMOLECULAR CHARGE CARRIER RECOMBINATION IN ORGANIC POLYMER STRUCTURES K. Arlauskas1, G. Juška1, A. J. Mozer2, N.S. Sariciftci2, F. Jean3, J.M. Nunzi3, A. Pivrikas4 and R. Österbacka4 1

2 3

Department of Solid State Ele11ctronics, Vilnius University, Vilnius, Lithuania. (LIOS) Linz Institute for Organic Solar Cells, Johannes Kepler University, Linz, Austria.

Equipe de Recherche Technologique Cellules Solaires photovoltaïques Plastiques, Université d’Angers, Angers, France 4

Department of Physics, Åbo Akademi University, Åbo, Finland.

Current scientific interest in organic materials is basically caused by possibility of obtaining a vide range of useful properties, relatively simple fabrication technology and promising wide range of applications for the electronic devices. However, low charge carrier mobility (µ) in organic polymers, compared to the crystalline semiconductors, causes Langevin-type recombination of the charge carriers (BL). This limits the range and possibilities of applications for the organic polymers, especially, in the devices operating at high charge carrier densities – such as solar cells. In this report we will demonstrate the importance and the methods of investigation of bimolecular recombination, and some experimental results obtained in different organic structures. The bimolecular recombination coefficient (B) can be measured: a) from the TOF SCLC transients using the short light pulses of various intensity for the surface photogeneration; b) from the collected charge and the reservoir extraction time dependence on the intensity of exciting light pulse using the integral TOF mode in case of bulk photogeneration; c) from the photo-CELIV technique using independent charge carrier density and mobility measurements, which allows to compare B with BL; d) from double injection transients, which gives the possibility to estimate B dependence on electric field and the ambipolar mobility of the charge carriers. Obtained experimental results demonstrate that in the single organic polymer layers Langevin recombination dominates, while in the junction of electron and hole transporting materials and, especially, in the bulk heterostructures B is much smaller than BL, caused by separate pathways for the electrons and holes.

E 115 FABRICATION OF PHOTOVOLTAIC DEVICES BY LAYER-BY-LAYER POLYELECTROLYTE DEPOSITION METHOD Wai Kin Chan, Ka Yan Kitty Man, Kai Wing Cheng, Chui Wan Tse Department of Chemistry, The University of Hong Kong, Pokaulam Road, Hong Kong Aeksandra B. Djurišić Department of Physics, The University of Hong Kong, Pokfulam Road, Hong Kong Abstract We report the fabrication of different photovoltaic devices using the layer-by-layer polyelectrolyte deposition method. Compared to other film forming techniques in polymers (e.g. spin-coating), this method can yield multilayer thin films with highly reproducible thickness (resolution up to few nm) easily. In addition, the deposition is easily to perform, and the waste of materials can be kept at minimum. In our system, the photosensitizing materials are based on metal containing polymers. Some examples of polymers are shown in the figure. The polymers consist of either ionic metal complex on the main chain or pendant ionic group. They were co-deposited with different charge transporting polyelectrolyte such as poly[2-(3-thienyl)ethoxy-4-butylsulfonate] (PHT). In addition, other semiconducting nanoparticles decorated with charged surface can also be used for deposition.

The photovoltaic response of the devices under simulated solar light irradiation was studied. From the photocurrent action spectra, it was confirmed that the excitation process was due to the metal complex sensitizers. The power conversion efficiency and fill factor were in the range -3

-1

between 10 – 10 % and 0.2 to 0.3, respectively.

E 121 Bright white organic light-emitting diode with dual doped blue and yellow-orange emitting layers Bernard Geffroy*, Noëlla Lemaître, Christine Denis, Pascal Maisse and Paul Raimond CEA/DRT/LITEN/DSEN/GENEC Laboratoire Cellules et Composants CEA/Saclay, 91191 Gif sur Yvette Cedex, France Organic Light Emitting Diodes (OLEDs) are actively considered as potential next generation of solid state lighting sources due to the tremendous progress in device luminous efficiency and the emerging viability as a commercial display technology. A white OLED has been fabricated employing a highly efficient doped blue material and a yellow-orange doped layer as emitting species. The device structure was ITO/CuPc/NPB:rubrene/DPVBi:PR3491/Alq3/LiF/Al. The blue electroluminescent layer is based on a DPVBi (4,4’-bis(2,2’-diphenylvinyl)biphenyl) host doped with a derivative of distyryl biphenyl molecule synthesized in the laboratory. White diodes can be obtained by further doping the hole transport layer (NPB) with rubrene, a highly efficient yellow fluorescent molecule. By properly tuning the doping rate in order to balance the blue and yellow-orange contribution of the diode emission, a fairly pure white light has been obtained with Commission Internationale de l’Eclairage (CIE) chromaticity coordinates of 0.30, 0.32 and external efficiencies of 3.7% and 8.8 cd/A at a current density of 10 mA/cm². Moreover, the CIE coordinates of the emitted light are quite stable for luminance ranging from 500 cd/m² to 5000 cd/m².

* Corresponding author. Tel : +33 (0)1 6908 4872; E-mail: [email protected]

F 163 VALENCE ELECTRONIC STRUCTURE AND TRAP STATES IN OFET MATERIALS

Sigurd Schrader Department of Engineering Physics, Faculty of Engineering, University of Applied Sciences Wildau, Wildau, Germany E-mail:[email protected]

Abstract Low-molecular and polymeric conjugated organic materials can be used as active part in electronic devices, forming e.g. the channel of organic field-effect transistors (OFETs). The valence electronic structure of such materials is investigated by combined application of electrical, optical and photoemission techniques. Angle resolved ultraviolet photoelectron spectroscopy (ARUPS) was applied both to thin layers of low molecular as well as to polymeric conjugated materials on conductive inorganic substrates (gold 111, gold coated silicon wafers and others), and provided detailed information of the occupied valence electronic states of these materials. In case of ordered layers, eg. formed from organised films of sexiphenyl, substituted phenyloxadiazoles or other conjugated materials, the band structure of the valence band of these materials was measured in detail. In special cases the size of the Brillouine zone could be determined from the experimental data. Scanning tunnelling spectroscopy in combination with optical spectroscopy provides information complementary to the photoemission measurements about the non-occupied valence electronic states and about other important quantities like exciton binding-energy in these materials. Besides the energetic boundary conditions as given by the valence band and conduction band states connected to the chemical structure of the materials, detailed information about trap states are required to understand charge transport in these organic semiconductors. Their energetic position depends e.g. on the disorder as usually present in organic semi-conducting materials but can also be coupled to chemical defects or impurities. A combination of techniques like thermoluminescence, thermally stimulated currents, time-of-flight technique, current-voltage characteristics and impedance spectroscopy is applied in order to extract information about energetic position and density of trap states, about attempt-to-escape frequency of trapped carriers and mobility of mobile carriers. Aspects of application of these materials are briefly discussed.

F 170 UNDERSTANDING EXCITONS IN OPTICAL ACTIVE POLYMERS. N. Kirova, LPS, Bât.510, Université Paris-Sud, 91405 Orsay, cedex We review the solid state physics approach to electronic and optical properties of conducting polymers and bring together languages of solid state theory for polymers and the quantum chemistry of oligomers. We consider polymers as generic one dimensional semiconductors with specific features of strongly correlated electronic systems. Our model combines the large distance electron-hole motion within an exciton, governed by long range Coulomb attraction with the strong intra-monomer electronic correlations, which results in effective intra-monomer electron-hole repulsion. We exploit the dielectric screening to go beyond the single chain picture and to compare excitons for polymers in solutions and in films. Our approach allows to connect , explain, exploit and organize such different experimental and numerical findings as shallow singlet and deep triplet excitons in phenylenes, anomaly in singlet-triplet exciton formation ratio, Ag-Bu crossing in polyenes, common 1/N energy dependencies in oligomers

F 173 CARRIER MOBILITY IN DOPED DISORDERED ORGANIC SEMICONDUCTORS V. I. Arkhipov,1 E. V. Emelianova,2 P. Heremans,1 H. Bässler3

1

IMEC, Kapeldreef 75, B-3001 Heverlee-Leuven, Belgium 2

Semiconductor Physics Laboratory, University of Leuven, Celestijnenlaan 200D,

B-3001 Heverlee-Leuven, Belgium 3

Institute of Physical, Nuclear and Macromolecular Chemistry, Philipps University of Marburg, HansMeerwein-Strasse, D-35032 Marburg, Germany

Experimental study of conductivity in doped poly(3-hexylthiophene) (P3HT) polymer films [1] have shown that (i) at low-to-moderate doping levels, the carrier mobility decreases with increasing dopant concentration while (ii) the mobility steeply increases at doping levels of around and larger than 1%. More recently, the authors of Ref. [2] directly compared the field-effect (FE) carrier mobility of P3HT and the mobility measured in electrochemically (EC) doped P3HT. The mobility of EC doped carriers at the moderate doping levels of 1% was found to be two orders of magnitude smaller than the FE mobility at the same doping level. A sharp rise of the mobility with the doping level was found for the EC doping while, in sharp contrast, the FE mobility had much smaller doping level dependence. The aim of the present work is to explain this striking difference between the two ways of doping. We suggest a model of carrier hopping in doped disordered organic semiconductors and show that this model is able to reproduce the experimentally observed behavior of the mobility. The model is based on the concept of strong coulomb interaction between charge carriers and ionized dopants. This interaction has to play an important role in disordered organic materials in which the dielectric constant is low and carriers are strongly localized within either individual molecules or conjugated molecular segments. As a matter of fact, doping of an organic semiconductor simultaneously produces extrinsic charge carriers and deep Coulomb traps for those carriers. Under such circumstances, dependences of the carrier mobility and conductivity upon doping level are determined by the trade-off between the increase of carrier density and creation of deep states in addition to the intrinsic density-ofstates (DOS) distribution. Recently, it has been shown both experimentally [3] and theoretically [4] that the Coulomb traps associated with ionized dopants strongly enhance energetic disorder manifested by expansion of the lower tail of the intrinsically Gaussian DOS gi(E). It was found [4] that, at low-tomoderate doping levels, carrier localization in the Coulomb traps prevails and the mobility decreases if the Coulomb-induced disorder is stronger than the intrinsic energetic disorder. Otherwise, excess carriers released from the Coulomb traps of dopants fill vacant deep intrinsic states and the mobility increases upon doping.

References [1] X. Jiang et al., Chem. Phys. Lett. 364, 616 (2002). [2] H. Shimotani, G. Diguet, and Y. Iwasa, Appl. Phys. Lett. 86, 022104 (2005). [3] I. N. Hulea et al., Phys. Rev. Lett. 93, 166601 (2004). [4] V. I. Arkhipov et al., Phys. Rev. B 71, 045214 (2005).

F 175 ON THE PROPERTIES OF POLYETHYLENEDITHIATHIOPHENE – THE SULPHUR CONTAINING ANALOGUE OF POLYETHYLENEDIOXYTHIOPHENE (PEDOT) A. Cravinoa,*, H. Neugebauera, A. Petrb, P. J. Skabarac, H. J. Spencerc, J. J. W. McDouallc, L. Dunschb, N. S. Sariciftcia a

Linz Institute for Organic Solar Cells (LIOS), Physical Chemistry, Johannes Kepler University Linz,

4040 Linz, Austria b

Institut für Festkoerper– und Werkstofforschung Dresden, Institut für Festkoerperforschung, Abteilung

Elektrochemie und leitfähige Polymere, 01069 Dresden, Germany c

Department of Chemistry, the University of Manchester, M13 9PL Manchester, United Kingdom

Poly(3,4-ethylenedithiathiophene) (PEDTT) is a polythiophene–like conjugated polymer where each thiophene ring is functionalized with an ethylenedithia–bridge. As such, PEDTT is the sulphur analogue of well-known poly(3,4-ethylenedioxythiophene) (PEDOT). While the presence of sulphur atoms in PEDTT - replacing the oxygen atoms of PEDOT - might explain the different electronic properties of the two polymers, the differences observed after their electrochemical oxidation (e.g. the different infrared active vibrational band patterns as well as the different nature of the produced charged states) are not trivial. In this paper, we report the spectroscopic properties of p–doped PEDTT in detail, as investigated by means of in–situ techniques such as UV-Vis-IR and ESR spectroelectrochemistry. AM1 calculations indicate that the different conformations adopted by neutral and oxidized PEDTT and PEDOT might explain their different electronic and spectroscopic behaviours. *

New permanent address: Chimie, Ingénierie Moléculaire et Matériaux d'Angers (CIMMA),

UMR 6200 du CNRS, 2, bd. Lavoisier, 49045 Angers, France.

F 181 ENERGETIC DISORDER AT THE INTERFACE BETWEEN DISORDERED ORGANIC MATERIAL AND METAL ELECTRODE

1 2

S.V. Novikov1 and G.G. Malliaras2 A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Moscow 119071, Russia Materials Science and Engineering, Cornell University, Ithaca, NY 14853-1501

The performance of any organic electronic device depends to a very large extent on effective carrier injection. For this reason injection in organic devices is field of active study. Recently it was recognized that energetic disorder in organic materials used in today's devices affects the injection efficiency [1,2]. First, disorder increases injection and, second, recently it was considered as a major reason for unusually weak temperature dependence of injection current [3,4]. The injection properties of metal-organic interfaces mostly depend on the properties of thin organic layer directly contacting with the metal. It is well known that the structure of this interface layer is typically different from the bulk structure of the organic material. In the literature [1,2] calculation of the effect of energetic disorder on the injection has been carried out using bulk disorder parameters (basically, width of the energy distribution). To some extent this could be explained by our lack of any detailed knowledge of the structure of interface layer. For example, it is well known that frequently a surface dipole layer is formed directly at the interface, providing abrupt leap in carrier energy in the range of 0.3-1 eV [5]. It is reasonable to assume that such a layer has some degree of disorder and, thus, induces additional energetic disorder in neighboring layers of organic materials [4]. Yet the magnitude of this additional disorder is unknown. We have showed that in the case where dipolar disorder provides a major part of the total disorder in polar organic materials very general conclusions can be made about the structure of the interface. Indeed, energetic disorder in polar organic materials is just a reflection of the disorder in the spatial distribution of electrostatic potential, generated by randomly situated and oriented dipoles. In the organic layer bounded by conducting electrodes this spatial distribution must obey a boundary condition at the electrode surface: at this surface the potential should be a constant. Thus, at the electrode surface there is no energetic disorder at all, irrespectively to how disordered is the material in the bulk, far away from the interface. This means that the magnitude of dipolar disorder (in fact, any disorder of electrostatic origin, e.g. quadrupolar [6]) increases while going away from the interface, asymptotically reaching its bulk value. For dipolar disorder the thickness of the interface layer where significant drop in the amplitude of the energetic disorder occurs is about 5 - 6 intersite distances. If a surface dipolar layer is formed at the interface, this picture needs to be modified. In this case the magnitude of the total disorder could decrease with the increase of the distance to the electrode, or it could still increase, depending on the relative amplitudes of the bulk and surface contributions. Yet in any case the use of bulk disorder parameters for calculation of the injection current density seems to be hardly justified. 1. V. I. Arkhipov, E. V. Emelianova, Y. H. Tak, and H. Bässler, J. Appl. Phys. 84, 848 (1998). 2. A.L. Burin and M.A. Ratner, J. Polymer Sci. B 41, 2601 (2003). 3. T. Van Woudenbergh, P. W. M. Blom, M. C. J. M. Vissenberg, and J. N. Huilberts, Appl. Phys. Lett. 79, 1697 (2001). 4. M. A. Baldo and S. R. Forrest, Phys. Rev. B 64, 085201 (2001). 5. D. Cohen and A. Kahn, Adv. Materials 15, 271 (2003). 6. S.V. Novikov and A.V. Vannikov, Mol. Crystals and Liquid Crystals 361, 89 (2001).

F 183 IMPROVED PERFORMANCE OF ORGANIC NANO-COMPOSITE SOLAR CELLS WITH REVERSE BIASED ANNEALING Ajay K. Pandey a, K. N. N .Unni a, H. Wang b, C. C. Oey b, A. B. Djurišić b, M. H. Xie b, Y. H. Leung b, K. K. Y. Man b, W. K. Chan b, P. C. Chui b and J. M. Nunzi a a

Laboratoire POMA,UMR CNRS 6136 Université d'Angers,49045 Angers b University of Hong Kong, Pokfulam Road, Hong Kong There have been tremendous efforts to realize the cheap and clean conversion of solar energy in order to address worlds growing energy demands (1). Organic semiconductors have the potential to play an important role and have been topic of intensive research in recent years. Power conversion efficiencies close to 4% have become possible by adopting different combinations both from solution based and thermally evaporated materials (2). The low intrinsic mobility and the solar spectrum mismatch of the commonly available donors and acceptors, pose the serious limitation to scale the efficiency further up. One way to address this obstacle is to combine the features of organic semiconductors with the suitable inorganic wide band gap semiconductors (3). Solar cells with organic donor and inorganic acceptor have been reported and are being studied by various research groups. Nano-porous TiO2 in combination with polymeric donors are most commonly studied among other organic-inorganic hybrid structures. Performance of such devices has so far been inferior to that of their all-organic counterparts (4). Major issue is to make a uniform filling of the organic donor in the matrix of TiO2 nano-porous layers, failing to which in turn leaves voids to act as charge trapping cites or causes localized dipoles leading to reduced power conversion efficiencies .Another problem encountered is the formation of counter diode due to the poor carrier selectiveness of the electrodes, resulting in a reduced filling factor and hence low extraction of the maximum converted power by the composition. We have performed some studies to address the above mentioned issues and are reporting here the improved performance of cells made by MEH-PPV and TiO2 nano-composites. It has been observed that annealing of the samples under reverse biased condition at an elevated temperature (100o C) helps re-orient the dipoles created by uneven filling of polymer inside the nano-composite matrix. Improvements were clearly observed as the current-voltage characteristics of the device became strongly asymmetric (in dark) with doubled filling factor and one order of magnitude higher short circuit current resulting in improved power conversion efficiency. To further analyze the approach we have performed experiments to address the origin of the counter diode formation in such compositions which, in common practice, is attributed to the poor carrier selectiveness of the electrodes. We observed that this was not the case always as the nature of such an appearance might originate from the ITO and TiO2 interface. To substantiate our claim, we measured the cell performance under AM 1.5 illumination in combination with an UV-cut filter and observed that the counter-diode disappeared totally or got reduced significantly. Further work is under way to study the phenomenon in a systematic and precise way. References: 1. B. O’Regan and M. Grätzel, Nature 1991 353, 737 2. C.J. Brabec, N.S. Sariciftci, J. C. Hummelen, Adv. Funct. Mater. 2001, 11, 15. 3. W. J. E. Beek, M. M. Wienk, R. A. J. Janssen, Adv. Mater. 2004, 16, 1009 4. M. Y. Song, J. K. Kim, A. Y. Kim, Synth. Met. 2003, 137, 1387

F 185 POLYMER BULK HETEROSTRUCTURES FOR CHARGE CARRIER PHOTOGENERATION J. Pfleger1, Q. T. Vu2, W. Plieth2 1

Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic 2

Institute of Physical Chemistry and Electrochemistry, Dresden University of Technology, Dresden, Germany

Solar energy conversion in devices fabricated of organic materials, preferably -conjugated polymers, is now an emerging field with promising targets. Low-cost production of mechanically flexible functional components would be the obvious advantage of such materials but there are several drawbacks that have to be overcome, like the low value of charge carrier mobility and poor photogeneration efficiency at low electric field. Contrary to inorganic semiconductors, in polymers the photogeneration of free charges upon photon absorption proceeds via an intermediate exciton-state formation, consisted of Coulombically bound electron and hole. For the efficient free charge carrier photogeneration a Schottky barrier or p-n juntion has to be realized that can facilitate the exciton dissociation into free charges. Such heterojunction was realized by two possible ways: (i) fabrication of polymer nanocomposites composed of p-type -conjugated polymer with a nanocrystalline fraction of n-type low-molecular weight material 2,9-di(pent-3-yl)-anthra[2,1,9-def:6,5,10-d’e’f’]diiso-quinoline-1,3,8,10-tetraone, and (ii) polymer nanocomposite composed of nanoparticles of inorganic semiconductor embedded in a conjugated polymer matrix. In our case, the large area heterojunction was realized using core/shell nanoparticles of TiO2 (size 25 nm) covered with 2 nm thick shell of low band-gap polythiophene. These core-shell nanoparticels were capable of an electrophoretic deposition in which the charged core/shell nanoparticles dispersed in ethanol were deposited on the semitransparent conductive substrate (ITO glass) in an applied external electric field. The photoelectrical sensitivity of this device was found to extend into the visible spectral region, corresponding to the polythiophene optical absorption spectrum. In the current-voltage characteristics under white light illumination (10 mW/cm2) an increase in the current of about 6 orders of magnitude can be observed compared to the current in dark. Unfortunately, only a small negative value of the open circuit voltage can be detected that limits the power efficiency. The EPD was found to be a suitable method to prepare composite layers on different conducting substrates (Pt, Al, steel and ITO). The results of Zeta-potential measurements show that, similarly to pure oxide nanoparticles, also the core/shell particles are charged positively when dispersed in alcohols and can be accelerated towards the cathode by an applied electric field. The kinetic studies performed in situ by quartz crystal balance monitor show that the layer growth starts at the electric field of about 5 Vcm-1. At the electric field 100 Vcm-1 a 1 µm thick composite layer can be completed within seconds. The reversible redox potential measurements together with optical absorption and photoconductivity spectra show that polythiophene remains to be stable even under relatively high potentials applied during the electrophoretic deposition. Considering the simplicity, fast operation rate and the possibility of covering surfaces of irregular shape, as well as the good quality of prepared films it was concluded that the electrophoretic deposition is a suitable process for the preparation of the conductive or semiconductive polymer composite layers. Financial support of the Grant Agency of the Academy of Sciences of the Czech Republic (Grant No. IAA4050406)

F 191 DEMONSTRATION OF A SOFTWARE FOR AUTOMATIC OPTIMIZATION OF THE ELECTROMAGNETIC FIELD IN ORGANIC SOLAR CELLS JJ. Simon, Ph. Torchio, F. Monestier, M. Cathelinaud and L. Escoubas Institut Fresnel, UMR-CNRS 6133, Ecole Généraliste d'Ingénieurs de Marseille, Domaine Universitaire de St Jérôme, 13397 Marseille Cedex 20, France.

abstract We present the results obtained using a software for automatic optimization of the electromagnetic field in organic solar cells. This numerical tool may be useful for any organic device having a multilayer thin-film structure. The analysis, based on the optical admittance, assumes that a plane wave is incident upon the multilayer device. Interference effects are taken into account inside the whole structure. Our software allows the calculation of the optical properties, the calculation of the distribution of the electromagnetic field with respect to the depth and gives routines for determining the optimal thicknesses of each layer with the view to localize the maximum of the square modulus of the normalised electromagnetic field in the photoactive area. Our software based on characteristic matrix equations resolution can receive the values of the optical constants (n, k) of each layer in tabular form for each wavelength in the desired spectral range. The (n, k) values can be experimentally measured by spectroscopic ellipsometry and recorded in the software. The principles of the method will be presented and some examples will be given: a global optimization under incident solar illumination in the wavelength range 300-600 nm is demonstrated with the following organic solar cell composed of interpenetrated networks of conjugated polymers: ITO/PEDOT:PSS/MEH-PPV:PCBM/LiF/Al. Our numerical method will also be applied to the optimal design of photovoltaic devices such as multi-junction cell or tandem cells).

F 193 ORGANIC FETs OBTAINED BY ZONE-CASTING TECHNIQUE P. Miskiewicz1, J. Jung1, I. Glowacki1, E. Gomar , D. Amabilino2, M. Mas-Torrent2, C. Rovira2, J. Veciana2, M. Heeney3, M. Shkunov3, W. Zhang3, J. Ulanski1 2

1

Department of Molecular Physics, Technical University of Lodz, 90-924 Lodz, Poland 2

Institut de Ciencia de Materials de Barcelona (CSIC), 08193-Cerdanyola, Spain 3 Merck Chemicals Ltd, Southampton SO16 7QD, United Kingdom e-mail: [email protected]

Zone-casting technique was developed over 20 years ago in order to produce oriented conducting polymer composites consisting of quasi-1D organic metals (like TTF-TCNQ) embedded in insulating polymer matrix [1, 2]. Such composites show extremely high anisotropy of conductivity, σ||/σ⊥ >106 [3]. Recently this technique has been successfully applied to produce oriented layers of liquid crystalline discotics [4, 5]. First FET produced by the zone-casting technique was based on hexa(n-dodecyl)hexaperi-benzo-coronene [6]. In this work we present an application of the zone-casting technique for producing oriented thin layers of the tetrathiafulvalene derivative: H37C18

S

S

S

S C18H37

H37C18

S

S

S

S C18H37

and of quaterthiophene (R = Propyl): R

S

S S

S

R

The zone-cast films show optical and electrical anisotropy. The FET devices were made using hydrophobic SiO2/Si substrates with the top-contact configuration. Very strong field effects were observed when the electrodes were oriented perpendicular to the casting direction. The charge carrier mobility and the On/Off ratio determined from the output and transfer characteristics are 0.08 cm2/Vs and 105 for the FET made of the tetrathiafulvalene derivative, and 0.07 cm2/Vs and 106 for the FET made of the quaterthiophene. Acknowledgements This work was financially supported through the EC NAIMO integrated project, No NMP4-CT-2004500355. [1] L. Burda, A. Tracz, T. Pakula, J. Ulanski and M. Kryszewski, J.Phys.D: Appl.Phys., 16, 1737 (1983). [2] A. Tracz, T. Pakula, J. Ulanski, M. Kryszewski, Polish Patent P-231177. [3] J.Ulanski, A.Tracz, E.El. Shafee, G.Debrue and R.Deltour, Synth. Met., 35, 221 (1990). [4] P. Miskiewicz, A. Rybak, J. Jung, I. Glowacki, J. Ulanski, Y. Geerts, M. Watson and K. Müllen, Synth. Met., 137, 905 (2003). [5] A. Tracz, J. K. Jeszka, M. D. Watson, W. Pisula, K. Mullen, T. Pakula, J. Am. Chem. Soc., 125, 1682 (2003). [6] P. Miskiewicz et al, unpublished results, presented at DISCEL Discussion Meeting, MPI-P, Mainz, March 10-11, 2003

G 083 ENVIRONMENTAL EFFECT ON THE NLO MOLECULAR RESPONSE IN GUEST-HOST MATERIALS M. Makowska-Janusik Solid State Department, Institute of Physics, Jan Dlugosz University, Al Armii Krajowej 13/15, PL-42201 Częstochowa, Poland, [email protected] Recently one can observe an increasing interest in nonlinear optical guest-host materials due to a possibility of incorporation of NLO active organic molecules in NLO no active layered polymeric medium. The strategy to develop useful NLO materials is to combine these two components and investigate an influence of the environmental effect on optical properties of guest chromophores. Optical linear and nonlinear susceptibilities are measured in condensed matter where the molecular properties are affected by the host matrix and may not be directly compared with the results of the theoretical calculations which yield electronic properties of isolated molecule. On the other hand, molecular simulations can help to explain the nature of the guest-host interaction and separate the different contribution of the material to the optical output signal. A goal of many theoretical works is to find appropriate model describing properties of molecules incorporated in polymeric matrix. The pyrazolo-quiniline (PAQ) derivatives are promising materials for optoelectronics and incorporated in poly(methyl-methacrylate) (PMMA) matrix can be considered like interesting materials for nonlinear optics. In the presented work the environmental effect of PMMA matrix on the linear and nonlinear optical properties of PQA derivatives is analysed. A structure of the PAQ/PMMA composite materials is theoretically simulated using molecular dynamics methods. Then, it is used to calculate the optical properties, particularly UV-absorption spectra and the first order nonlinear susceptibility of the composite material. Polarizability and hyperpolarizability of the considered molecules are calculated using HartreeFock and density functional approaches. Environmental effects are taken into account using local-field theory and the obtained results are compared to the experimental data published earlier.

G 090 ORGANIC SEMICONDUCTING POLYMER DEVICES BASED ON ORIENTED POLYMER THIN FILMS Aleksandra Apostoluk1,*, Licinio Rocha1, Céline Fiorini-Debuisschert1, Carole Sentein1, Paul Raimond1, Alessandro Fraleoni-Morgera2, Leonardo Setti2, Jean-Michel Nunzi3 1

Centre d’Etudes Atomiques CEA-Saclay, CEA-DRT-LITEN, DSEN/GENEC/L2C, bât. 451 Laboratoire Cellules et Composants, 91191 Gif-sur-Yvette Cedex, France 2

University of Bologna

Dept. of Industrial and Materials Chemistry Faculty of Industrial Chemistry Viale Risorgimento 4, 40136 Bologna, ITALY 3

Université d’Angers, UFR : Sciences

Laboratoire de Propriétés Optiques des Matériaux et Applications (POMA), UMR CNRS 6136 2 Boulevard Lavoisier, 49045 Angers Cedex 01, FRANCE

We demonstrate the rectifying behaviour induced in an oriented polymer material [1]. The presence of a rectifying junction is mandatory for the efficiency improvement of a polymer semiconductor device like an organic solar cell. A distributed p-n junction is realised in a polymeric single-layer photovoltaic cell through molecular orientation. The polar molecular alignment in the initially centrosymmetric structure is induced through electric field or optical ordering of polar molecules contained in a polymer matrix. In order quantify the internal field stored in devices resulting from the polar molecular orientation, we propose a technique based on nonlinear optical techniques was developed, the Solid State Electric Field Induced Second Harmonic Generation (SEFISHG) method. The second harmonic generation proved to be sensitive to the presence of any internal electric field in the polymer layers [2] and permits to optimise the sample orientation parameters, like orientation field, sample temperature, poling duration and cooling conditions to obtain the largest stable orientation. The experiments performed are a step towards a full characterisation of the stocked internal field and allowed for the investigation of an in-situ thermally assisted electrical field poling method. The SEFISHG permits as well to measure the electron work function difference between the two electrode materials before orientation [3]. Studies are now under way concerning semiconducting polymers grafted with polar molecules in order to find an appropriate trap-free high Tg semiconducting polymer and to avoid thermal and photoinduced disorientation phenomena. References [1] C. Sentein et al., Adv. Mat. 9, 809 (1997). [2] C. Sentein et al., Opt. Mat. 9, 316 (1998). [3] C. Sentein et al., Synth. Met.102, 989 (1999).

G 092 INDIVIDUAL MOLECULE ORBITAL MEDIATED TRANSPORT THROUGH SIGMA-PISIGMA SYSTEMS IN AN ATOMICALLY CONTROLLED THREETERMINAL DEVICE. Reza Dabirian,1 Yann-Vaï Kervennic,2 Cornelis A. van Walree,1 Daniel Vanmaekelbergh,3 Jos M. Thijssen,2 Herre S. J. van der Zant,2 Leonardus W. Jenneskens,1,* 1

Debye Institute, Organic Chemistry and Catalysis, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands. 2 Kavli Institute of Nanoscience, Delft University of Technology, PO Box 5046, 2600 GA, The Netherlands. 3 Debye Institute, Condensed Matter and Interfaces, Utrecht University, Princetonplein 1, 3584 CC Utrecht, The Netherlands.

Conduction via individual π-conjugated organic molecules in molecular devices has been shown to generally involve Coulomb blockade tunneling characteristics1 i. e. exhibiting step-like features. Here we demonstrate that by applying sulfur end-functionalized oligo(cyclohexylidenes) as molecular spacers in a three-terminal device (see Figure), coherent resonant electron transfer through the systems occurs at low temperatures. No step-wise Coulomb blockade features are discernible for the three-ring disulfide derivative. The three-terminal devices were prepared by using a recently developed technology,2 which combines e-beam lithography and electrochemical etching to allow the creation of nanogaps between Au electrodes on the single-atom scale (see Figure). The sulfur end-functionalized oligo(cyclohexylidenes), which contain a σ−π−σ orbital topology, have been demonstrated by means of He(I) photoelectron spectroscopy (PES), ab initio RHF/6-31G* calculations and optical studies to possess through-bond orbital coupling interactions.3 An analysis of the data shows that apparently extensive orbital re-hybridization occurs between the (molecular) orbitals of the sulfur end-functionalized oligo(cyclohexylidenes) spacer and those of the connecting gold leads. The resistivity of the three-ring disulfide derivative decreases to the extent that coherent transport with no step-like features is observed. A similar device containing the analogous mono-sulfur derivative did not give rise to the same transport mechanism; this suggests that re-hybridization between the gold electrodes and our organic three-ring spacer is imperative for conduction.

(1) (2) (3)

Selzer, Y.; Cabassi, M. A.; Mayer, T. S.; Allara, D. L. J. Am. Chem. Soc. 2004, 126, 4052-4053. Kervennic, Y. V.; Vanmaekelbergh, D.; Kouwenhoven, L. P.; van der Zant, H. S. J. Appl. Phys. Lett. 83, 3782 (2003). Marsman, A .W.; Havenith, R. W. A.; Bethke, S.; Jenneskens, L. W.; Gleiter, R.; van Lenthe, J. H.; Lutz, M.; Spek, A. L. J. Org. Chem. 2000, 65, 4584-4592. Bakkers, E. P. A. M.; Marsman, A. W.; Jenneskens, L. W.; Vanmaekelbergh, D. Angew. Chem. Int. Ed. 2000, 39, 2297-2299.

G 094 LANGMUIR-BLODGETT FILMS AND NON-LINEAR OPTICAL PROPERTIES OF AMPHIPHILIC AZOBENZENES BEARING POLY (ETHYLENE GLYCOL) SEGMENTS E. Rivera1*, Carmen Becerril1, Roberto Salazar1, M.P. Carreón-Castro2 Gloria Huerta1 and O. MoralesSaavedra3 1) Instituto de Investigaciones en Materiales UNAM, circuito exterior, Ciudad Universitaria, C.P. 04510 México D. F. México 2) Instituto de Ciencias Nucleares UNAM, circuito exterior, Ciudad Universitaria, C.P. 04510, México D. F. México 3) CCADET-UNAM, circuito exterior, Ciudad Universitaria, C.P. 04510, Apartado Postal 70-186, México D. F. México Z- and Y–type Langmuir-Blodgett thin films (LB) were prepared with a series of novel azo-dyes a bearing endcapped poly(ethylene glycol) segments such as N-methyl-N-{4-[(E)-(4-nitrophenyl)diazenyl]phenyl}-N-(3, 6, 9trioxadecas-1-yl)amine (RED-PEGM-3) N-methyl-N-{4-[(E)-(4-nitrophenyl)diazenyl] phenyl}-N-(3, 6, 9, 12, 15, 18, 21, 24-octaoxapentaeicos-1-yl)amine (RED-PEGM-8) and their non end-capped homologues with different n values. These dyes are also suitable for the fabrication of Sol-Gel optical materials. The preparation of the multi-layer LBsystems and the grain size of the Sol-Gel RED-PEGM-8 doped materials were monitored by AFM. The optical properties of these thin films and Sol-Gel samples were studied by absorption spectroscopy. The results for the last case were compared to those previously observed in casted films. The presence of both H and J-type aggregates was confirmed for our LB-samples. In addition, non-linear optical properties (NLO) like second harmonic generation (SHG) were studied for these azo-dyes in both, LB- and Sol-Gel-sample presentations.

G 103 NON-LINEAR OPTICAL PROPERTIES OF POLYMER SYSTEMS WITH THE POLED INDANDIONE DERIVATIVES AS CHROMOPHORES. M. Rutkis1,2, A. Vembris1,2, V. Zauls1, A. Tokmakov1, E. Fonavs1,2. 1

Institute of Solid State Physics, University of Latvia, 8 Kengaraga St., 1063 Riga, Latvia, [email protected] 2 Institute of Physical Energetics, Latvian Academy of Sciences, 21 Aizkraukles St., 1006 Riga, Latvia Non-linear optical devices are expected to play a major role in the new emerging field of photonics which is the analogue to electronics in that it describes the technology in which photons instead of electrons are used to acquire, store, transmit and process information and images and has been labelled as the technology of the 21st century. The advancement in this field depends very much on the development and characterization of new class of materials possessing high non-linear optical properties both at the molecular and bulk levels and capable of forming organized noncentro-symmetric molecular structures for device application. One of the possibilities to create such a material is poled polymer film. They can be host – guest systems, where chromophores are dispersed in polymer matrix, or polymers with chromophores chemically attached to polymer backbone. Optimisation of the polymer structure (matrix or backbone), concentration of chromophore and poling conditions are essential to reach our objective – high non- linear optical susceptibility tensor values. Two groups of chromophores have been investigated – one based on indandione-1,3 pyridinium betaine (IPB, R1=R2=R3=H), another on dimethylaminobenzylidene 1, 3 - indandione O (DMABI, R1=H, R2=CH3): R1

O R1 N R2

OIPB

R3

O

DMABI

N R2 H3C

The potential of indandione derivatives as chromophores for organic materials with prospective usage in non-linear optical applications, as well as success in the synthetic strategy and quantum chemical calculation results has been described in review articles [1, 2]. Although the both classes of the molecules exhibit high molecular non-linearity (for both IPB and DMABI β0~ 40 x 10-30 esu), formation of bulk non-centro symmetrical materials with high non-linearity is hard task. At the present paper we would like to review our achievements in the optimisation of the NLO polymer materials with the indandione derivatives as a chromophores.

1. E.A. Silinsh (1996) in “Photoactive Organic Materials. Science and Applications”, Kluver Academic Publishers, Dardrecht, Boston, London, 2. O.Neilands, I.Muzikante (2003), in “Organic Nanophotonics, Proceedings of the NATO Advanced Workshop”, NATO Science Series II, Vol.100, Kluwer Academic Publishers, pp.447-462