摘要
Due to their superior photoluminescence(PL)quantum yield(QY) and tunable optical band gap,all-inorganic CsPbBr_3 perovskite quantum dots(QDs) have attracted intensive attention for the application in solar cells,light emitting diodes(LED),photodetectors and laser devices.In this scenario,the stability of such materials becomes a critical factor to be revealed.We hereby investigated the long-term stability of as-synthesized CsPbBr_3 QDs suspended in toluene at various environmental conditions.We found light illumination would induce drastic photo-degradation of CsPbBr_3 QDs.The steady-state spectroscopy,transmission electron microscopy(TEM),and X-ray diffraction(XRD)verified that CsPbBr_3 QDs tend to aggregate to form larger particles under continuous light soaking.In addition,decreasing PL QY of the QDs during light soaking indicates the formation of trap sites.Our work reveals that the main origin of instability in CsPbBr_3 QDs and provides reference to engineer such QDs towards optimal device application.
全无机CsPbBr_3钙钛矿量子点因其优异的发光性能,而在太阳能电池、发光二极管、光探头和激光器件等应用研究领域受到广泛关注.基于此,我们研究了CsPbBr_3钙钛矿量子点在不同光照、气氛和温度条件下的稳定性.光照下,量子点表面缺陷态的产生和量子点的聚集促使量子点的发光效率降低,吸收和发光光谱发生红移.透射电子显微镜和X-光单晶衍射实验结果表明,在光照下量子点发生了聚集进而形成了大尺寸的晶体.我们的工作表明光照是影响CsPbBr_3钙钛矿量子点稳定性的决定性因素,因此需要改善其光稳定性从而优化CsPbBr_3钙钛矿量子点光电器件性能.
基金
supported by the National Priorities Research Program from the Qatar National Research Fund(a member of Qatar Foundation)(NPRP7-227-1-034)
the Swedish Foundation for International Cooperation in Research and Higher Education(STINT,CH2015-6232)
the Academy of Finland,and the Program of Study Abroad for Young Teachers by Agricultural University of Hebei
