Solution-processed quantum-dot light-emitting diodes combining ultrahigh operational stability, shelf stability, and luminance

The shelf-stability issue, originating from the ZnO-induced positive aging effect, poses a significant challenge to industrializing the display technology based on solution-processed quantum-dot light-emitting diodes (QLEDs). Currently, none of the proposed solutions can simultaneously inhibit exciton quenching caused by the ZnO-based electron-transporting layer (ETL) and retain other advantages of ZnO. Here in this work, we propose a bilayer design of ETL in which a buffer layer assembled of SnO 2 nanoparticles (NPs) suppresses the QD-ETL exciton quenching and tunes charge balance while ZnO NPs provide high electron conductivity. As a result, the bottom-emitting QLED combining capped ZnO and SnO 2 buffer exhibit a maximum luminance over 100,000 cd m −2 and a T 95 operational lifetime averaging 6200 h at 1000 cd m −2 on the premise of entirely inhibiting positive aging.