Mesoporous Silica-Coated CsPbX₃ Nanocrystals with High Stability and Ion-Exchange Resistance for Bright White-Emitting Displays

Abstract

All-inorganic metal halide perovskite (CsPbX 3 ) nanocrystals (NCs) have attracted much attention due to their excellent photoelectric properties. However, CsPbX 3 NCs are easily affected by polar solvents because of their ionic crystal nature, which led to luminescence quenching. In this paper, mesoporous silica nanoparticles (MSNs) were used as carriers to anchor CsPbX 3 NCs for effectively improving the resistance of CsPbX 3 NCs in polar solvents. CsPbX 3 @MSN composites were created via a sol−gel-assisted ligand exchanging process. The photoluminescence (PL) intensity of the CsPbX 3 @MSNs composite still maintained more than 50% of their initial value after 60 min of treatment with water and ethanol. The mesoporous structures of SiO 2 spheres facilitate efficient coupling of CsPbX 3 NCs to improve the stability and decrease surface defects, resulting in high PL quantum yield. CsPbX 3 @MSN composites have unique advantages for white-light-emitting diodes (LEDs) as solid-state luminescent materials. White LED devices were fabricated using CsPbX 3 @MSN composites as the solid-state light-emitting conversion layer. The color temperature was 6838 K, and the luminous efficiency was 8.9 lm/W. Its coincidence degree with the gamut space specified by NTSC 1953 is 135%, and the coincidence degree with the gamut space specified by ITU-R B.T. 2020 (Rec. 2020) is 95%.

Charge Transfer in Photoexcited Cesium–Lead Halide Perovskite Nanocrystals: Review of Materials and Applications

“…While the majority of the time, these PNCs are used in photovoltaics, photodetectors, and light-emitting diode (LED) devices, − only limited research has been done toward photocatalysis. − Apart from carrier diffusion, the crystalline nature, energy levels, and exciton binding energies of halide perovskites have played an essential role in efficient charge separation . Recently, PNCs have been used as photocatalysts by Park et al in signifying H 2 evolution from a saturated hydroiodic acid solution in the presence of MA–lead iodide perovskite as the photocatalyst to advance the reaction mechanism .…”

Modulating the Carrier Relaxation Dynamics in Heterovalently (Bi3+) Doped CsPbBr3 Nanocrystals

“…The decay components for 10% Bi-doped CsPbBr 3 NCs are as follows: τ 1 = 0.6 ns (89%), τ 2 = 2.1 ns (9%), and τ 3 = 14 ns (2%) with an average lifetime of 1.0 ± 0.1 ns. The τ 2 component arises due to the excitonic recombination process, and the other two components (τ 1 and τ 3 ) are associated with the trap-mediated radiative recombination process. − The analysis shows that the τ 1 and τ 3 components significantly decrease with an increase in their amplitude due to the incorporation of Bi into CsPbBr 3 NCs. This suggests that the trap-mediated relaxation pathway for the charge carriers increases upon Bi doping.…”

Bright and Stable Luminescence of CsPbX3 Nanocrystals in ZrO2 Skeletons for White Light Emitting Diodes

“…20 Shi et al demonstrated that CsPbX 3 NCs were anchored to the carrier mesoporous silicon nanoparticles to prevent perovskites from being damaged in polar solvents. 21 Hu and co-workers prepared the CsPbX 3 /SiO 2 and CsPbBr 3 /Ta 2 O 5 Janus nanoparticles via a water trigger method and sol−gel approach, respectively, which effectively improved the stability of NCs. 22 Li et al successfully synthesized the CsPbBr 3 silica/alumina monolith by the sol−gel method, which has amazing stability and high luminescence in toluene.…”

“…However, in the metal organic framework, the color of the materials itself affects luminescence of perovskite materials. The conventional inorganic coating materials include SiO 2 , Ta 2 O 5 , TiO 2 , and alumina − and also are used as the matrix material. Yang’s group synchronously achieved the successful preparation of CsPbBr 3 @SiO 2 core–shell nanoparticles and Janus structure, enhancing its stability under humid conditions .…”