Green Emissive Electroluminescent Devices Based on Colloidal Quantum Dots

Colloidal quantum dot (QD)-based light-emitting diodes (QLEDs) hold tremendous potential for next-generation solid-state lighting and full-color display technologies and are the focus of extensive research since many years. In particular, green QLEDs, which are more friendly to the human eye, see significant advancements in terms of external quantum efficiency and operational stability, largely due to the design optimization and structural regulation of QD materials and the architecture regulation of devices. While numerous reviews exist on QDs and QLEDs in general, comprehensive summaries specifically focusing on green QLEDs—covering aspects such as synthesis, structure, performance, mechanisms, and regulation strategies—remain scarce. This gap hinders subsequent researchers from developing higher-performance green QLEDs. In response, this review adopts a material classification approach, summarizing green-emitting cadmium-based, lead-based perovskite, and heavy-metal-free QDs. Alongside discussing the latest research progress of these three types of QDs, strategies to enhance device performance from a mechanistic perspective, including QD crystal structure and composition engineering, QD surface defect passivation, and device architecture modulation are also proposed. Finally, existing challenges are highlighted and feasible solutions are proposed, offering valuable insights for the future development of green QLEDs.