In this review, we discuss diffusion-driven currents in several types of organic-semiconductor diodes, including light-emitting diodes, solar cells and single-carrier devices. It is demonstrated that the ideality factor of the current and photon emission contains important information about charge transport and recombination in such devices. Most importantly, the effects of charge trapping and trap-assisted recombination can be explored. An analytical model is derived for diffusion-driven currents, which can explain the current–voltage behavior of organic diodes and allows determination of the injection barriers and built-in voltages.
- Gert-Jan A H Wetzelaer
- Paul W M Blom
