Measurements of deviation from Einstein relation in PVK-based photorefractive polymers by photoelectromotive-force technique

Insitut fu ¨r Physikalische Chemie, Luxemburger str. 116, Koln 50939, Germany~Received 20 October 2003; published 19 May 2004!Non-steady-state photoelectromotive-force effect is proposed for experimental measurements of deviationfrom Einstein relation in amorphous monopolar photoconductors. For widely used poly~N-vinylcarbazole!-based polymer films this technique yielded an approximately three-fold difference between the measureddiffusion coefficient-to-mobility ratio (D/m) and its conventional value in crystalline photoconductors (’78vs 25 mV!. The mobility, lifetime, and diffusion coefficient of the photoholes were evaluated in these experi-ments as ’7.9310