In Situ Growth of CsPbBr3 Perovskite Nanocrystals in Lead‐Based Matrix toward Significantly Enhanced Water/Photo Stabilities

Perovskite nanocrystals (NCs) are considered as the next‐generation platforms for optoelectronic applications, but their poor stability greatly restricts their development. Here, we present a facile composite strategy to synthesize highly stable CsPbBr3/Pb‐MA composite by in situ embedding the CsPbBr3 NCs in a C16H14Br2O6Pb2 (Pb‐MA) organometallic compound (MOC). The CsPbBr3/Pb‐MA composite powders show intense green emission at 519 nm, with a photoluminescence quantum yield of about 48.5% and a full width at half‐maximum of about 17 nm. More interestingly, benefitted from the protection of MOC, the CsPbBr3/Pb‐MA composites can maintain 43% and 83% of initial intensity after being illuminated under blue light for 36 h and being immersed in water for 192 h, respectively. Compared to the original CsPbBr3 NCs, the light/water stability of CsPbBr3/Pb‐MA composites is enhanced by about 40 and 700 times (the PL intensities maintain at about 60% of the initial one), respectively. As a proof‐of‐concept, the as‐fabricated devices exhibit a wide color gamut, 97.7% and 98.2% of Rec. 2020 for white light‐emitting diodes and laser diodes, respectively. These findings demonstrate that the combination of MOC and perovskite NCs is an optimized strategy for the exploitation of high‐performance perovskite composites for their future optoelectronic applications. A stable lead‐based C16H14Br2O6Pb2 (Pb‐MA) organometallic compound is designed and synthesized, as the framework for the perovskite NCs. The obtained CsPbBr3/Pb‐MA composites show excellent stability and optical performance. The display devices based on the composites exhibit a wide color gamut, 97.7% of Rec. 2020 for white light‐emitting diodes and 98.2% of Rec. 2020 for laser diodes.