In-situ sintered CsPbBr3/CsPb2Br5 perovskite nanocrystals into mesoporous silica for white high-efficiency LEDs

• Published in: Journal of solid state chemistry Vol. 310; p. 123032
• Main Authors: Hong, Guo-hui, Li, Jiao, Su, Zhong-min, Li, Xiao, Li, Sha-sha, Sun, Jing, Liu, Fang-bin, Liu, Yan-ling
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.06.2022
• Subjects: Mesoporous silica; Nanocrystals; Perovskite; Sintering; White light-emitting diodes; Perovskite; Nanocrystals; Mesoporous silica; Sintering; White light-emitting diodes
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1016/j.jssc.2022.123032

As the most promising luminescence candidate materials, all-inorganic perovskite materials have made outstanding contributions in the field of optoelectronics. Meantime, it is greatly needed to tackle the characteristics of ionic crystals to wider practical application. In this paper, two stable ceramic-like perovskite CsPbBr3/CsPb2Br5 nanocrystals (CPB1/CPB2 NCs) are encapsulated into mesoporous silica (SiO2) to form CPB1/CPB2@SiO2 via soft film plate method by controlling the sintering temperatures. CPB1/CPB2@SiO2 powders illustrate green light-emitting, reaching a photoluminescence quantum yield (PLQY) of 82.4% and can be stable for two months in water with no drops in the intensity of the emission spectrum. Futhermore, CPB1/CPB2@SiO2 shows excellent resilience in thermal cycling experiments. Finally, all-inorganic white light-emitting diodes (white LED) were prepared on the surface of GaN blue chip using green light-emitting CPB1/CPB2@SiO2 powder and red light-emitting K2SiF6: Mn4+ (KSF), light efficiency of 31.5 lm/W and color gamut wide as 155% NTSC. These results indicate that the CPB1/CPB2@SiO2 composites would have potential practical applications in white WLEDs. Cubic and tetragonal perovskites (CPB1/CPB2@SiO2) were synthesized in the pores of mesoporous silica by in-situ sintering process. The resultant CPB1/CPB2@SiO2 shows excellent optical properties and stability. [Display omitted] •Mixed-phase perovskites are synthesized by a simple one-step calcination method (CPB1/CPB2@SiO2).•CPB1/CPB2@SiO2 has good stability and high quantum efficiency (∼80%) for LEDs built with blue chips and red phosphors.•This work provide hints to improve perovskite stability and quantum efficiency.