One‐Step Loading on Natural Mineral Halloysite Nanotube: An Effective Way to Enhance the Stability of Perovskite CsPbX₃ (X = Cl, Br, I) Quantum Dots

Abstract

Recently, all inorganic halide perovskite CsPbX 3 (X = Cl, Br, I) quantum dots (QDs) have emerged as promising candidates for optoelectronic devices because of high photoluminescence quantum yield (PLQY), tunable emission in the whole visible region, narrow-band emission and high charge-carrier mobility compared to traditional materials. [3,4] However, the CsPbX 3 QDs have yet to deliver the desired performance owing to the poor humid stability and thermal stability as well as low photoinduced stability, which has limited its further practical application. [5] A principal challenge for CsPbX 3 QDs to apply in optoelectronic area is the design of highly efficient luminescence materials with superior stability. [6,7] Therefore, intensive studies for improving stabilities of CsPbX 3 (X = Cl, Br, I) QDs have sprung up like mushrooms. Embedding the perovskite nanocrystals into polymer matrices by incorporation of organic ligands is an effective strategy to enhance the moistureresistance performance. [8] For examples, Huang et al. successfully induced a polyhedral oligomeric silsesquioxane via facile surface treatment, and Wei et al. also developed a swellingshrinking strategy by packing in crosslinked polystyrene beads for improving the moisture-resistant property of Currently, poor luminescence stability seriously impedes the practical application of inorganic halide perovskite (CsPbX 3 , X = Cl, Br, and I) quantum dots (QDs) in optoelectronic devices. In present work, CsPbX 3 QDs are successfully assembled on natural mineral halloysite nanotubes (HNTs) for improving the luminescence performances. Monodispersed CsPbX 3 QDs are arranged on two edges of HNTs in a highly ordered manner, which possibly originates from the electrostatic interaction between halogen ion and surface hydroxyl (SurOH 2 + ) on the section face of HNTs. As expected, the photoluminescence (PL) performances of CsPbX 3 @HNTs nanocomposites are obviously improved. The PL intensity still can be maintained even 80% when working at 100 °C. Almost no emission degradation is observed after storing in an open ambient condition for 28 days. Moreover, the PL intensity also maintains 82% of room temperature (RT) intensity after continuously being illuminated by 365 nm UV lamps for 144 h. Excellent white light with Commission Internationale de l'Eclairage (CIE) chromaticity coordinates (0.34, 0.32) of the white light-emitting diodes (w-LEDs) fabricated by CsPbBr 3 @HNTs, CsPbBr 1.2 Cl 1.8 @HNTs, and CsPbBr 1.2 I 1.8 @HNTs phosphors are achieved. This work opens up a new insight in achieving stable CsPbX 3 QD-based multifunctional materials by designing nanocomposites with natural clay mineral.

Research Progress on the Stability of CsPbX3 Nanocrystals

“…4 (a) Schematic diagram of Lewis base surface passivation strategy for CsPbX 3 nanocrystals; (b) Theoretical calculation of the binding energy of mono-and dicarboxylic acids on the surface of CsPbI 3 nanocrystals [34] ; (c) Schematic diagram of OPA and OAm-CsPbX 3 surface passivation strategies and photos after multiple purifications [35] ; (d) Surface passivation strategy with zwitterionic ligands (sulfobetaines, phosphocholines and γ-amino acids) [36] 铅的结合作用力较弱, 在多次提纯和长时间存储 后仍然会出现团聚长大的现象。不过, 选用路易 斯碱配体来增强 CsPbX 3 纳米晶的稳定性是行之 有 效 的 。 例 如 , 潘 军 等 [34] [37] ; (c) OAm-CsPbBr 3 纳米晶表面富含 PbBr x (左)和 OAm/OA-CsPbBr 3 纳米晶表面富溴(右)的示意图 [11] ; (d) OAm/OA-CsPbBr 3 纳米晶(上)和 OAm-CsPbBr 3 纳米晶(下)在水溶液中保持稳定的发光照片 [11] Fig. 5 (a) Passivation strategies with different ligands (OAm, OA and DBSA) on the surface of CsPbBr 3 nanocrystals and (b) the corresponding exciton recombination processes [37] ; (c) Schematic diagram of PbBr x -rich surface of OAm-CsPbBr 3 nanocrystals (left) and Br-rich surface of OAm/OA-CsPbBr 3 nanocrystals (right) [11] ; (d) Photographs showing the resistance of different samples against water treatment of OAm/OA-CsPbBr 3 nanocrystals (above) and OAm-CsPbBr 3 nanocrystals (below) [11] 围环境的相互作用 [43][44][45][46][47] 。此外, 由于氧化物扩散速 率很低, 氧化硅、氧化钛、三氧化二铝和氧化锆等 氧化物经常作为阻挡层保护有机发光二极管、荧光 粉和金属免受氧化和腐蚀 [48][49] 。李良教授课题组 [50] 利用简单的溶胶-凝胶法将 [52] 、 Rb 4 PbBr 6 [53] 、 氟化钙 [54] 、冠醚 [55] 、SiN x /SiN x O y /SiO y [56] 、纳米管 [57] 也可与 [51] ; (b) CsPbBr 3 @SiO 2 纳米晶的普通透射电镜照片(TEM)和 高分辨透射电镜照片(HRTEM)以及水稳定性的实物照片 [60] ; (c) CsPbBr 3 /CdS 纳米晶的示意图(左)、 HRTEM 照片(中)以及连续脉冲激光照射 CsPbBr 3 /CdS 纳米晶的稳定性曲线(右) [67] Fig. 6 (a) Schematic diagram of CPB-DBAE@SiO 2 preparation process [51] ; (b) Transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM) images of CsPbBr 3 @SiO 2 nanocrystals and photographs of water stability…”

In‐Situ Anchoring Pb‐Free Cs3Bi2Br9@BiOBr Quantum Dots on NHx‐Rich Silica with Enhanced Blue Emission and Satisfactory Stability for Photocatalytic Toluene Oxidation

“…[19] To date, considerable effort has focused on the stabilization of perovskite QDs through encapsulation techniques using organic polymer or inorganic matrices. [20][21][22][23][24][25][26] In contrast, inorganic matrices were more stable and could be directly compatible with the proven packaging technology of commercial white light-emitting diodes (LEDs). [20,27] Additionally, surfacefunctionalized inorganic matrices were able to provide rich sites for the nucleation and growth of perovskite QDs, which was beneficial for effectively restraining fluorescence degradation and improving stability.…”

Highly Photoluminescent Yb-Doped CsPbBrI2 Nanocrystals in Ethylene Vinyl Acetate Composite Films for Wide Color Gamut Backlight Displays

“…Metal halide CsPbX 3 (X = Cl, Br, I) perovskite nanocrystals (NCs) have attracted many researchers because of their high photoluminescent quantum yield 1−3 (PLQY) and tunable emission wavelength. 4,5 Because CsPbX 3 NCs have excellent optical properties, they are widely used in white light-emitting diodes (WLEDs), 6,7 lasers, 8,9 photodetectors, 10,11 and solar cells. 12,13 Compared with traditional light sources, CsPbX 3 NCs have higher color purity and wider color gamut, which are of great significance to the field of backlight displays.…”