Highly stable and luminescent silica-coated perovskite quantum dots at nanoscale-particle level via nonpolar solvent synthesis

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 407; p. 128001
• Main Authors: Gao, Fei, Yang, Weiqiang, Liu, Xiuling, Li, Yuanzheng, Liu, Weizhen, Xu, Haiyang, Liu, Yichun
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.03.2021
• Subjects: Core@shell structure; Perovskite quantum dots; Stability; White LED; Core@shell structure; Stability; Perovskite quantum dots; White LED
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2020.128001

[Display omitted] •Monodisperse CsPbBr3@SiO2 NCs are prepared by one-pot route in nonpolar solvents.•These NCs exhibit high photoluminescence quantum yield of 87%.•The core@shell NCs exhibit evidently improved stability compared to bare QDs.•LEDs with high CRI and efficiency are constructed with these CsPbX3@SiO2 NCs. Currently, unsatisfactory optical stability and toxicity of all-inorganic lead halide perovskite (CsPbX3, X  = Cl, Br, and I) quantum dots (QDs) with excellent photoelectric properties is a major obstacle for their practical application. In this work, the CsPbBr3 QDs were assembled into SiO2 shell via nonpolar solvent synthesis, and monodisperse CsPbBr3@SiO2 nanocomposites (NCs) with high photoluminescence quantum yield (PLQY) of ~87% were successfully prepared. Moreover, the introduced hydrophobic and multibranched trioctylphosphine oxide (TOPO) effectively suppressed the hydrolysis rate of tetraethoxysilane (TEOS), resulting in the formation of core@shell NCs at a nanoscale-particle level. Benefiting from the protection of TOPO and SiO2 shell, the CsPbBr3@SiO2 NCs exhibit remarkably improved stability against thermal treatment, UV irradiation and water compared to the bare perovskite-QDs. Notably, the anion-exchange reaction among different perovskite-QDs was completely inhibited. To improve stability of iodide-substituted perovskite-QDs and expand emission wavelength, the CsPbBr0.6I2.4@SiO2 NCs with PLQY of 75% were also successfully prepared by similar strategy. White light-emitting-diodes (WLEDs) were designed by combining CsPbBr3@SiO2 NCs with CsPbBr0.6I2.4@SiO2 NCs onto blue GaN chips. Bright white-light with high color-rendering index of 90 and luminous efficiency of 80 lm W−1 were achieved from these WLEDs, indicating the synthesized perovskite NCs possess huge potentiality in displays and solid-state lighting.