Integrating light emission and switching: A review of progress in light-emitting transistors

Light-emitting transistors (LETs) are emerging as a transformative class of optoelectronic devices that integrate light emission and switching functions within a single architecture, offering unique opportunities for next-generation displays, transparent electronics, and reducing the cost and complexity of display manufacture. Although significant progress has been made, advances in LETs remain fragmented across different material strategies and device designs. This short review addresses that gap by consolidating recent developments, spanning low-voltage hybrid architectures, high–color-purity quantum dot emitters, transparent electrodes, interfacial doping, and ambipolar charge injection. This consolidation provides a unified perspective that provides insight into the important role of charge-injection mechanisms in advanced LETs. By integrating these achievements and outlining future directions, this short review aims to provide both fundamental insights and practical guidance for advancing LET research toward real-world applications, including simplified displays, integrated photonics and opto-neuromorphic computing.