Meeting High Stability and Efficiency in Hybrid Light-Emitting Diodes Based on SiO₂/ZrO₂ Coated CsPbBr₃ Perovskite Nanocrystals

Significant advances are realized in perovskite-converted hybrid light-emitting diodes (pc-HLEDs). However, long-living devices at high efficiencies still represent a major milestone with average stabilities of '200 h at ≈50 lm W⁻¹ under low applied currents ('15 mA). Herein, a dual metal oxide-coated CsPbBr₃@SiO₂/ZrO₂ composite is prepared in a one-pot synthesis through the kinetic control of the sol–gel reaction, followed by a gentle drying process in air. These hybrid nanoparticles show photoluminescence quantum yields of ≈65% that are stable under temperature, ambient, and irradiation stress scenarios. This is translated to pc-HLEDs with a near-unity conversion efficiency at any applied current, high efficiencies around 75 lm W⁻¹, and one of the most remarkable stabilities of ≈200 and 700 h at 100 and 10 mA, respectively. In addition, the device degradation mechanism is thoughtfully rationalized comparing devices operating under ambient/inert conditions. As such, this work provides three milestones: i) a new room temperature one-pot protocol to realize the first SiO₂/ZrO₂ metal oxide coating that effectively protects the emitting perovskite nanoparticle core, ii) one of the most stable and efficient pc-HLEDs operating under ambient condition at any applied current, and iii) new insights for the degradation of pc-HLEDs.