One Hundred-Nanometer-Sized CsPbBr_3/m-SiO_2 Composites Prepared via Molten-Salts Synthesis are Optimal Green Phosphors for LCD Display Devices

摘要

The exploitation of the optimal optical properties of lead halide perovskitenanocrystals in optoelectronic devices is mainly hindered by the low stabilityof such materials. Here, a molten-salts approach is developed to encapsulateCsPbBr_3 nanocrystals (together with KNO_3, NaNO_3, and KBr inorganicsalts) inside different nanoscale mesoporous SiO_2 host matrices, having sizesbetween 100 and 300 nm. The comparison between optical properties andstability of the products, including the previously reported ≥600-nm-sizedCsPbBr_3/m-SiO_2 composite, indicates that 100-nm-sized CsPbBr_3/m-SiO_2particles feature the best stability against humidity, light irradiation and heat,and exhibit a green (peaked at 517 nm) narrow photoluminescence (full widthat half maximum of 18 nm) with high quantum yield (77%). Such propertiesmake these composite particles optimal green phosphors for down conversionliquid crystal displays (LCDs). Indeed, the authors demonstrate thata proof-of-concept 7-in. LCD in which the green color conversion layer is apolymer film loaded with 100-nm-sized CsPbBr_3/m-SiO_2 particles, featuresan optimal white emission (with correlated color temperature of 6861 K),that is close to the reference white point of NTSC, and covers 92% of NTSCstandard color gamut area of CIE1931, higher than that of a reference commercialLCD (Dell XPS 15 7590 laptop).