Enhanced performance of quantum dot light-emitting diodes enabled by zirconium doped SnO₂ as electron transport...

Next-generation display and lighting based on quantum dot light-emitting diodes (QLEDs) require a balanced electron injection of electron transport layers (ETLs). However, classical ZnO nanoparticles (NPs) as ETLs face inherent defects such as excessive electron injection and positive aging effects, urgently requiring the development of new types of ETL materials. Here, we show that high stability SnO₂ NPs as ETL can significantly improve the QLED performance to 100567 cd·m^-2 luminance, 14.3% maximum external quantum efficiency, and 13.1 cd·A^-1 maximum current efficiency using traditional device structures after optimizing the film thickness and annealing the temperature. Furthermore, experimental tests reveal that by doping Zr⁴⁺ ions, the size of SnO₂ NPs will reduce, dispersion will improve, and energy level will shift up. As expected, when using Zr-SnO₂ NPs as the ETL, the maximum external quantum efficiency can reach 16.6%, which is close to the state-of-the-art QLEDs based on ZnO ETL. This work opens the door for developing novel, to the best of our knowledge, type ETLs for QLEDs.