Luminescent Properties of a Silicone-Carbazolyl Polyfluorene Hybrid Material for Device Applications Tatiana D. Martins, * Ines V. P. Yoshida, Teresa D. Z. Atvars * Summary: In the present work, bilayered hybrids obtained by hydrosilylation of polysiloxane with carbazolyl moieties (Sil-Cz) and polyfluorene (Sil-PFO) had their photophysical behavior, morphological characteristics and interaction properties studied for applications in electroluminescent devices. Fluorescence spectra of the Sil-Cz did not show emission in the excimer/aggregate region (from 400 to 500 nm). This is an unexpected behavior since most of the carbazole-based materials present excimer and aggregation. Nonetheless, this unusual observation was also predicted by geometry optimization calculations. Fluorescence spectra were taken for both compounds separately and for the bilayered system show some evidence of interaction between carbazolyl and polyfluorene moieties, giving rise to the supposi- tion that the can form a system with tunable luminescent properties. Keywords: carbazole; hybrid materials; polyfluorene; silicone Introduction Silicones form a wide class of silicon-oxide based polymers with excelent thermal and oxidative properties, low surface tension, high flexibility, high chemical stability and very high adhesion on several substrates. [1] In general, silicones are neither photolu- minescent nor electroluminescent materi- als. Hydrosilylation is one type of reaction which occurs under mild conditions [2] that can be used to prepare photoluminescent [3] as well as electroluminescent silicones. However, electroluminescent materials have shown poor performance in devices, so far. [4] Polyfluorene and its derivatives form a promissing class of materials for both electroluminescent and photovoltaic devices. [5,6] Electroluminescence from blue to red using polyfluorene polymers and copolymers have been prepared and tested. [7–11] However, in general the ele- troluminescence efficiency of the polyfluor- enes can be enhanced when a hole transport layer is introduced in the device. [12] One common hole transport injector is the polycarbazole and several electrolumines- cent devices using polyfluorene and poly- carbazole have been reported. [13] The eletroluminescence device perfor- mance is also very sensitive to the quality of the heterojunction between the electrodes and the polymer layers. [14] The electrical properties of this heterojunction can be improved by using a conductive polymer layer in between the metalic electrode and the polymeric active layer. The PED- OT:PSS mixture is often used with very good results. [15] Therefore, for a good electroluminescent device some require- ments must be fullfilled: (i) metalic electro- des with adequate work function; (ii) an intermediate layer of a conductive polymer, (iii) a hole injection layer and (iv) an active layer with high electroemission efficiency. Thus, not only a good preparation of the devices are necessary, but also strategies for new materials. In this work we describe the synthesis and photophysical properties of a new material with potential properties for electroluminescent applications. This new material has some special characteristics Macromol. Symp. 2010, 296, 170–175 DOI: 10.1002/masy.201051025 170 Instituto de Quı ´mica, Universidade Estadual de Cam- pinas, P.O. Box 6154, Campinas, 13084-971, SP, Brazil E-mail: tati.duque@gmail.com; tatvars@iqm.unicamp.br Copyright ß 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim wileyonlinelibrary.com