Water-induced fluorescence enhancement of lead-free cesium bismuth halide quantum dots by 130% for stable white light-emitting devices. Issue 6 (4th February 2020)

• Record Type: Journal Article
• Authors: Ma, Zhuang-Zhuang; Shi, Zhi-Feng; Wang, Lin-Tao; Zhang, Fei; Wu, Di; Yang, Dong-Wen; Chen, Xu; Zhang, Yu; Shan, Chong-Xin; Li, Xin-Jian
• Is Part Of: Nanoscale. Volume 12:Issue 6(2020)
• Page Start: 3637
• Page End: 3645
• Publication Date: 2020-02-04
• Subjects: Nanoscience -- Periodicals; Nanotechnology -- Periodicals; 620.505
• DOI: 10.1039/c9nr10075j
• Languages: English
• ISSNs: 2040-3364

Abstract

Abstract : We proposed a strategy of employing water-induced Cs3 Bi2 Br9 /BiOBr nanocomposites to achieve a substantial enhancement in photoluminescence quantum yield by ∼130%. Abstract : Recently, the discovery and development of lead-free perovskite quantum dots (QDs) that are eco-friendly and stable has become an active research area in low-cost lighting and display fields. However, the low photoluminescence quantum yield (PLQY) caused by the residual surface states of such QDs severely hinders their practical applications and commercialization. In this work, a strategy of employing water-induced nanocomposites was proposed to improve the PLQY of cesium bismuth halide (Cs3 Bi2 X9 ) QDs, and a substantial enhancement by ∼130% (from 20.2% to 46.4%) was achieved by an optimized water treatment of Cs3 Bi2 Br9 QDs. A detailed analysis indicated that Cs3 Bi2 Br9 /BiOBr nanocomposites, in which the Cs3 Bi2 Br9 QD core was encapsulated into a BiOBr matrix, can effectively suppress the surface defects of QDs, resulting in a longer PL lifetime and a larger exciton binding energy compared with the pristine sample. Finally, the Cs3 Bi2 Br9 /BiOBr nanocomposites were used as the color-converting phosphors for down-conversion white light-emitting devices, which show a good operation stability in ambient air, significantly better than the reference device constructed with conventional lead-halide perovskites. We believe that the method used here provides an effective strategy to improve the fluorescence efficiency of lead-free perovskite QDs, which will create opportunities for their applications in lighting and displays.