Tuning of threshold voltage by interfacial carrier doping in organic single crystal ambipolar light-emitting transistors and their bright electroluminescence

Organic light-emitting field-effect transistors, based on a p-bis[(p-styryl)styryl] benzene (P5V4) single crystal, that possess high mobilities of over 0.1 cm(2)/V s for both electrons and holes were fabricated. For a small charge injection barrier and successive formation of high exciton density in the carrier recombination zone, the hole accumulation threshold voltage was significantly reduced by interfacial hole doping based on electron transfer from P5V4 molecules to a molybdenum oxide layer. The threshold voltage for hole accumulation was drastically decreased from -80 +/- 3 to 2 +/- 3 V, leading to dual charge injection and accumulation of a very high current density of J>100 A cm(-2) with intense edge electroluminescence.