Key challenges in the development of organic light-emitting transistors (OLETs) are blocking both scientific research and practical applications of these devices, e.g., the absence of high-mobility emissive organic semiconductor materials, low device efficiency, and color tunability. Here, we report a novel device configuration called the energy transfer organic light-emitting transistor (ET-OLET) that is intended to overcome these challenges. An organic fluorescent dye-doped polymethyl methacrylate (PMMA) layer is inserted below the conventional high-mobility organic semiconductor layer in a single-component OLET to separate the functions of the charge transport and light-emitting layers, thus making the challenge to essentially integrate the high mobility and emissive functions within a single organic semiconductor in a conventional OLET or multilayer OLET unnecessary. In this architecture, there is little change in mobility, but the external quantum efficiency (EQE) of the ET-OLET is more than six times that of the conventional OLET because of the efficient Förster resonance energy transfer, which avoids exciton-charge annihilation. In addition, the emission color can be tuned from blue to white to green-yellow using the source-drain and gate voltages. The proposed structure is promising for use with electrically pumped organic lasers.

Organic light-emitting transistors (OLETs) integrate the functions of light-emitting diodes and field-effect transistors into a unique device, opening a new door for optoelectronics. However, there is still a challenge due to the absence of high quality organic semiconductors for OLETs. Herein, we reported a novel molecule 2,6-di(anthracen-2-yl)naphthalene (2,6-DAN), which exhibited mobility of up to 19 cm²·V^-1·s^-1 and an absolute fluorescence quantum yield of 37.09%, which are good values for organic semiconductors. Moreover, OLETs based on 2,6-DAN single crystals showed bright yellowish-green emission and well-balanced ambipolar charge transport. The excellent ratio of hole to electron mobility can reach up to 0.86, which is superior to most single-component OLETs in typical device configurations reported so far.