Synergetic Effect of Postsynthetic Water Treatment on the Enhanced Photoluminescence and Stability of CsPbX3 (X = Cl, Br, I) Perovskite Nanocrystals

Abstract

All inorganic cesium lead halide CsPbX 3 (X = Cl, Br, I) perovskite nanocrystals (NCs) are generally considered to be sensitive and even decompose when exposed to ambient humidity. Herein, we perform a well-controlled investigation of the effect of postsynthetic water treatment of the as-prepared CsPbX 3 NCs on the photoluminescence quantum yields (PLQYs) and stability, and one can find that the surface defective layer of CsPbX 3 NCs can be dissolved into water and we can further separate the supernatant CsPbX 3 NCs hexane solution from the water, which improves the PLQYs of CsPbCl 3, CsPbBr 3, CsPbI 3 from 5%, 69.3%, 68.1% to 78.5%, 95.5%, 91%, respectively. As a synergetic effect, a trace amount of residual water facilitated the hydrolysis of tetramethyl orthosilicate, leading to the formation of SiO 2 -coated CsPbX 3 NCs with high stability. The stable green-emitting CsPbBr 3 /SiO 2 composite is used as an example to combine with red K 2 SiF 6:Mn 4+ to fabricate the light-emitting diodes device on the blue InGaN chip, which displays wide color gamut (128% of National Television Standard Committee standard), providing the possibility for liquid-crystal display backlight utilization.