Suppressing thermal quenching of lead halide perovskite nanocrystals by constructing a wide-bandgap surface layer for achieving thermally stable white light-emitting diodes.

Lead halide perovskite nanocrystals as promising ultrapure emitters are outstanding candidates for next-generation light-emitting diodes (LEDs) and display applications, but the thermal quenching behavior of light emission has severely hampered their real-world applications. Here, we report an anion passivation strategy to suppress the emission thermal quenching behavior of CsPbBr 3 perovskite nanocrystals. By treating with specific anions (such as SO 4 2- , OH - , and F - ions), the corresponding wide-bandgap passivation layers, PbSO 4 , Pb(OH) 2 , and PbF 2 , were obtained. They not only repair the surface defects of CsPbBr 3 nanocrystals but also stabilize the phase structure of the inner CsPbBr 3 core by constructing a core-shell like structure. The photoluminescence thermal resistance experiments show that the treated sample could preserve 79% of its original emission intensity up to 373 K, far superior to that (17%) of pristine CsPbBr 3 . Based on the thermally stable CsPbBr 3 nanocrystals, we achieved temperature-stable white LED devices with a stable electroluminescence spectrum, color gamut and color coordinates in thermal stress tests (up to 373 K).