CsPbBr 3 @Glass Nanocomposite with Green‐Emitting External Quantum Efficiency of 75% for Backlit Display

Robust amorphous glass protected CsPbBr 3 (CsPbBr 3 @glass) perovskite quantum dots (PeQDs) with ultra‐pure green emission and superior long‐term stability are highly desirable for developing wide‐color‐gamut liquid crystal displays. However, most of the reported CsPbBr 3 @glass nanocomposites are subject to low external quantum efficiency (EQE). This work demonstrates that ZrO 2 additive has an “accumulation” effect on the borosilicate glass network structure to promote in situ nucleation/growth of PeQDs inside glass rather than self‐crystallization. This effect is beneficial in reducing surface defects, improving the quality of PeQDs, and thus boosting radiative recombination of excitons. As a consequence, the as‐prepared CsPbBr 3 @glass shows a record EQE of up to 75% and can pass the accelerated aging tests at 85 °C/85% RH for 1000 h and blue light irradiation over 2000 h. Finally, a prototype display using CsPbBr 3 @glass‐based straight‐down backlit unit is designed and gains more favorable responses in blind selection tests for its high brightness of 2647 cd m −2 and high color purity of 88%. The findings will pave the way for realizing the commercial application of CsPbBr 3 @glass nanocomposite in PeQDs‐converted backlit display.