CHAPTER 15: Light-emitting Transistors With Ambipolar Materials

Organic light-emitting transistors (OLETs) can incorporate gate-modulated electrical switching functions and light-emitting characteristics in a single device, which has attracted great interest from both academia and industry. Among these, OLETs with ambipolar materials have the capability of transporting both holes and electrons depending on the applied voltages, and they commonly demonstrate higher emission efficiency than unipolar devices. The light emission zone can be adjusted in the channel by modulating the gate and source–drain voltages. Well-balanced carrier mobilities between holes and electrons are thus preferred. Meanwhile, the state of highly efficient OLETs with ambipolar materials and a plausible method to solve some problems have been demonstrated. This chapter mainly concentrates on device physics and architectures in the progression of ambipolar OLETs, including devices made from thin films, single crystals, heterojunction structures and perovskite semiconductors, for the purpose of providing a comprehensive understanding of the intrinsic mechanisms of ambipolar OLETs.