Zhao Jiangtao, Liu Mei, Fang Li, Jiang Shenlong, Zhou Jingtian, Ding Huaiyi, Huang Hongwen, Wen Wen, Luo Zhenlin, Zhang Qun, Wang Xiaoping, Gao Chen
National Synchrotron Radiation Laboratory and CAS Key Laboratory of Materials for Energy Conversion, University of Science and Technology of China , Hefei, Anhui 230026, China.
Hefei National Laboratory for Physical Sciences at the Microscale, Key Laboratory of Strongly-Coupled Quantum Matter Physics of Chinese Academy of Sciences, Department of Chemical Physics, University of Science and Technology of China , Hefei, Anhui 230026, China.
J Phys Chem Lett. 2017 Jul 6;8(13):3115-3121. doi: 10.1021/acs.jpclett.7b01083. Epub 2017 Jun 22.
Understanding the big discrepancy in the photoluminesence quantum yields (PLQYs) of nanoscale colloidal materials with varied morphologies is of great significance to its property optimization and functional application. Using different shaped CsPbBr nanocrystals with the same fabrication processes as model, quantitative synchrotron radiation X-ray diffraction analysis reveals the increasing trend in lattice strain values of the nanocrystals: nanocube, nanoplate, nanowire. Furthermore, transient spectroscopic measurements reveal the same trend in the defect quantities of these nanocrystals. These experimental results unambiguously point out that large lattice strain existing in CsPbBr nanoparticles induces more crystal defects and thus decreases the PLQY, implying that lattice strain is a key factor other than the surface defect to dominate the PLQY of colloidal photoluminesence materials.
了解具有不同形貌的纳米级胶体材料在光致发光量子产率（PLQYs）方面的巨大差异，对其性能优化和功能应用具有重要意义。以具有相同制备工艺的不同形状的CsPbBr纳米晶体为模型，定量同步辐射X射线衍射分析揭示了纳米晶体晶格应变值的增加趋势：纳米立方体、纳米片、纳米线。此外，瞬态光谱测量揭示了这些纳米晶体在缺陷数量上的相同趋势。这些实验结果明确指出，CsPbBr纳米颗粒中存在的大晶格应变会诱导更多的晶体缺陷，从而降低PLQY，这意味着晶格应变是除表面缺陷之外主导胶体光致发光材料PLQY的关键因素。
