Recent advances in ambipolar organic light-emitting transistors: materials and devices

Achieving balanced ambipolar transport in organic light-emitting transistors (OLETs) is crucial for realizing high-performance electroluminescence and advancing integrated optoelectronics. However, this goal remains challenging due to the imbalanced charge injection and transport for most organic semiconductors. Encouragingly, significant effort has been made through two complementary approaches: molecular engineering to develop ambipolar high-mobility emissive semiconductors, and device architecture optimization to compensate for material limitations. The latter encompasses asymmetric electrodes, interface modification layers, multi-layer device structures, and dual-gate device structures. This review summarizes recent advances in ambipolar OLETs from both materials and device perspectives, with emphasis on the interplay between intrinsic molecular properties and extrinsic device design. Finally, we briefly discuss the persistent challenges and future prospects for achieving high-efficiency ambipolar OLETs.