Efficient Quantum-Dot Light-Emitting Diodes Based on Solvent-Annealed SnO₂ Electron-Transport Layers

Due to the sensitivity of ZnO nanoparticles to water and oxygen, the hybrid quantum-dot light-emitting devices (QLEDs) based on ZnO electron-transport layers (ETLs) suffer from shelf stability and uncontrollable positive aging problems. Tin oxide (SnO 2 ) is considered as an ideal alternative to ZnO as the ETL in QLEDs to improve their shelf stability. Currently, the SnO 2 -based device still suffers from poor efficiency. Herein solvent vapor annealing (SVA) is employed to reduce the roughness of SnO 2 nanoparticle films, which suppresses the leakage current and enhances the device performance. Compared with the device with pristine SnO 2, the maximum brightness and current efficiency (10.8 cd/A) of QLEDs based on solvent vapor annealed SnO 2 are enhanced by 25.3% and 36.6%, respectively, being comparable to the ZnO device (11.0 cd/A). Moreover, SVA processing also has a positive effect on the device shelf stability, which is attributed to the dense interface between SnO 2 and quantum dots due to the reduced surface roughness of SnO 2 films.