钙钛矿(结构)
量子点
材料科学
光致发光
纳米晶
发光二极管
量子产额
热稳定性
卤化物
发光
二极管
光电子学
八面体
胶体
化学工程
纳米技术
化学
无机化学
光学
结晶学
晶体结构
物理化学
荧光
工程类
物理
作者
Hyeonjung Kim,Jong Hyun Park,Kangyong Kim,Dongryeol Lee,Myoung Hoon Song,Jongnam Park
标识
DOI:10.1002/advs.202104660
摘要
Although metal halide perovskites are candidate high-performance light-emitting diode (LED) materials, blue perovskite LEDs are problematic: mixed-halide materials are susceptible to phase segregation and bromide-based perovskite quantum dots (QDs) have low stability. Herein, a novel strategy for highly efficient, stable cesium lead bromide (CsPbBr3 ) QDs via in situ surface reconstruction of CsPbBr3 -Cs4 PbBr6 nanocrystals (NCs) is reported. By controlling precursor reactivity, the ratio of CsPbBr3 to Cs4 PbBr6 NCs is successfully modulated. A high photoluminescence quantum yield (PLQY) of >90% at 470 nm is obtained because octahedron CsPbBr3 QD surface defects are removed by the Cs4 PbBr6 NCs. The defect-engineered QDs exhibit high colloidal stability, retaining >90% of their initial PLQY after >120 days of ambient storage. Furthermore, thermal stability is demonstrated by a lack of heat-induced aggregation at 120 °C. Blue LEDs fabricated from CsPbBr3 QDs with reconstructed surfaces exhibit a maximum external quantum efficiency of 4.65% at 480 nm and excellent spectral stability.
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