Synthesis of CsPbX3 (X =Cl/Br,Br,and Br/I)@SiO2/PMMA composite films as color-conversion materials for achieving tunable multi-color and white light emission

• 作者: Varnakavi Naresh Byung Hyo Kim Nohyun Lee
• 来源期刊: 纳米研究（英文版）
• 年，卷（期）: 2021,（4）
• 所属期刊栏目: Research Articles
• 页码范围: 1187-1194
• 页数: 8页
• 语种: 英文

摘要

All-norganic cesium lead halide based perovskite nanocrystals (PNCs) exhibit promising optoelectronic properties,but their poor stability and anion exchange reaction limit their broad commercial applications.Herein,we demonstrated the successful synthesis of blue-green-red emitting CsPbX3 (X =Cl/Br,Br,and Br/I) PNCs via hot injection method,followed by silica-coating and embedding in poly(methylmethacrylate) (PMMA) matrix.The photoluminescence (PL) spectra of SiO2/PMMA-coated PNCs can be tuned continuously by regulating precursor composition ratio,from blue (CsPb(Cl0.55/Br0.5)3;460 nm) to red (CsPb(Br0.4/I0.6)3 via green(CsPbBr3;519 nm).The PNCs composite films exhibit improved stability (thermal-,moisture-,and photo-stability) because of the barrier formed by SiO2/PMMA coating and also displayed exceptional photoluminascent quantum yield (PLQY of blue,green,and red-emitting SiO2/PMMA coated PNCs are 37％,86％,and 71％,respectively) with longer lifetimes inhibiting anion exchange.Eventually,the PNCs-encapsulated SiO2/PMMA composite films were integrated into the UV LED chip as down-converting materials to construct a prototype white-peLED unit.The designed white-peLED unit demonstrated bright white light generating CIE coordinates (0.349,0.350),a luminous efficiency (LE) of 39.2％ and a color rendering index (CRI) of 84.7.The wide color gamut of 121.47％ of NTSC and 98.56％ of Rec.2020 is also achieved with the built w-LED system.Therefore,the results demonstrated that CsPbX3 (X =CI/Br,Br,and Br/I) PNCs@SiO2/PMMA composite films can be employed as efficient UV to visible color conversion materials for white-LEDs and backlighting.