Analysis of photogeneration in a doped polymer system in terms of a kinetic model for electric-field-assisted dissociation of charge-transfer states

The photogeneration process in a 40:60 triphenylamine/Lexan system doped with a boron diketonate acceptor has been analyzed in terms of a kinetic model for field-assisted dissociation of charge carriers. The best fit of theory to experimental data is obtained if one assumes a Gaussian distribution of charge-transfer radii. A short-range mobility in triphenylamine/Lexan of order 10−2 cm2/V s is predicted assuming a purely coulombic electron-pair interaction. For the system studied, the most probable charge-transfer radius is 0.54 nm with a quantum yield for charge-transfer states of 0.93. The present model also predicts temperature-dependent quantum efficiencies for the doped system more accurately than does Onsager’s 1938 theory of geminate recombination.