Novel organic light-emitting transistors with PN-heteroboundary carrier recombination sites fabricated by lift-off patterning of organic semiconductor thin films

The authors have devised a novel organic light-emitting transistor (OLET) with a PN-heteroboundary combined with hole and electron transport materials (in other words, p-type and n-type organic semiconductors) along carrier channels. In this device, a clear modulation of the current and luminance with the gate voltage was observed. A luminance of 100 cd/m² or more has been observed at the source–source voltage of 15 V with the turn-on voltage of 10 V or less, which is lower than that of OLETs based on a single organic material. The horizontal PN-heteroboundary structure has been implemented for the first time by using the photolithographic patterning of organic semiconductor thin films. This patterning technique can be applied to the fabrication of not only the OLETs reported in this work, but also to organic integrated circuits or organic displays.