Photocarrier generation and bipolar transport in diphenoquinone doped polymethylphenylsilane thin films

Bipolar transport and photocarrier generation processes in thin films of 3,5-dimethyl-3',5'-di- tert-butyl-4,4'-diphenoquinone (MBDQ) doped polymethylphenylsilane (PMPS) are studied in terms of optical absorption, photoluminescence, the standard time-of-flight, and electroabsorption experiments. With increasing MBDQ concentration, the electron drift mobility is observable above 30 wt. % MBDQ addition (5.0x10(-7) cm(2)/Vs at 40 wt. % MBDQ addition) and the hole drift mobility is unchanged (similar to1.0x10(-4) cm(2)/Vs) for 0-40 wt. % MBDQ addition. The photocarrier generation efficiency is increased by an order of magnitude over pristine PMPS for 30-40 wt. % MBDQ addition in a visible spectral range. The electroabsorption experiments of MBDQ/PMPS composites show that the existence of charge transfer states becomes evident with increasing MBDQ concentration, which facilitate the photocarrier generation in the spectral range. (C) 2002 American Institute of Physics.