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 ${\text{(5.0×10}}^{\text{−7}} {\mathrm{cm}}^{\mathrm{2}}\mathrm{/Vs}$ at 40 wt. % MBDQ addition) and the hole drift mobility is unchanged ${\text{(∼1.0×10}}^{\text{−4}} {\mathrm{cm}}^{\mathrm{2}}\mathrm{/Vs})$ 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.