Light-Emitting Field-Effect Transistors Having Metal Electrodes Modified with an Organic Thin Film

We have improved the emission properties and the carrier mobilities of organic light-emitting field-effect transistors (OLEFETs) by modifying the metal electrode(s) with a thin film of n-type thiophene/phenylene co-oligomer (TPCO). Their semiconductor layer was a p-type TPCO crystal. When we used the modified electrode for electron injection, the device exhibited eight times higher emission intensity than a device with unmodified electrodes. By contrast, employing the modified electrode as the hole injection contact, we achieved the maximum hole mobility of 0.11 cm(2).V-1.s(-1) under the hole-enhancement mode. The modified electrodes effectively functioned for injecting both electrons and holes into the p-type crystal. The origin of this is briefly discussed. (C) 2012 The Japan Society of Applied Physics