TiO2:polymer bulk-heterojunction thin films made from a miscible new carbazole based TiO2 precursor with poly(N-vinylcarbazole) for enhanced charge transfer properties

Autor: Didier Léonard, Vincent Barlier, Joel Davenas, Véronique Bounor-Legaré, Gisèle Boiteux
Rok vydání: 2009
Předmět:
Zdroj: Materials Chemistry and Physics. 115:429-433
ISSN: 0254-0584
DOI: 10.1016/j.matchemphys.2009.01.003
Popis: TiO2:polymer bulk-heterojunctions (BHJ) have been elaborated from hydrolysis–condensation reactions of a TiO2 precursor in contact to the surrounding air humidity in a polymer thin film. A new precursor: tetrakis(9H-carbazole-9-yl-ethyl-oxy) titanium [Ti(OeCarb)4], has been synthesized as a TiO2 precursor to form a blend with Poly(N-vinylcarbazole) (PVK) which is the archetype of non-conjugated photoconducting polymer with strong electron-donor properties. This new precursor is expected to enhance the materials miscibility because of the chemical structure of the ligand close to the PVK repetitive unit and to inhibit premature hydrolysis by a strong steric hindrance. Commercial titanium isopropoxide [Ti(iOPr)4] was used as a reference to study the influence of the chemical structure of the precursor on BHJ properties. Photoluminescence studies have shown charge transfer enhancement when Ti(OeCarb)4 is used. In order to understand this ligand effect, photoluminescence (PL) responses were correlated with surface chemical composition (XPS) and topography (AFM) of thin films. Results have shown that Ti(OeCarb)4 allows a better miscibility between TiO2 and PVK. The lower reactivity of Ti(OeCarb)4 to hydrolysis and its chemical structure close to the repetitive unit structure of the polymer are believed to play a main role in the BHJ property improvement.
Databáze: OpenAIRE
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