Zhao Liang, Yin Changzhen, Long Ting, Hu Peng, Yang Zhenyu
MOE Laboratory of Bioinorganic and Synthetic Chemistry, Lehn Institute of Functional Materials, School of Chemistry, Sun Yat-sen University, Guangzhou 510275, Guangdong, China.
Langmuir. 2020 Mar 31;36(12):3064-3071. doi: 10.1021/acs.langmuir.0c00278. Epub 2020 Mar 18.
Colloidal perovskite nanocrystals (NCs) have shown promise in visible and near-infrared light emission compared with conventional quantum dots because of their sharp and highly efficient emission. Light-driven halide exchange offers high degrees of tunability of perovskite NC composition and photoluminescence properties. A remaining challenge is the incomplete change between bromide and chloride due to the presence of radical quenchers. Herein, an optimized halide exchange method of perovskite NCs is reported. Chloroform is used as the solvent and the precursor to effectively generate halide radicals and ions under ultraviolet light irradiation in an inert atmosphere. This strategy achieves complete crystal transformation in colloidal perovskite NCs such as CsPbBr-to-CsPbCl and CsPbBr-to-CsPbCl. The exchange reaction rate can be further tuned by the presence of B-site dopants such as Zn and Ce. The dopant cations are partially remained in the exchanged perovskite NCs, indicating the predominance of thermodynamic control in the crystal transformation.
与传统量子点相比，胶体钙钛矿纳米晶体（NCs）因其尖锐且高效的发光特性，在可见光和近红外光发射方面展现出了潜力。光驱动卤化物交换为钙钛矿NCs的组成和光致发光特性提供了高度的可调性。由于自由基猝灭剂的存在，溴化物和氯化物之间的不完全转变仍是一个挑战。在此，报道了一种优化的钙钛矿NCs卤化物交换方法。在惰性气氛中，氯仿用作溶剂和前驱体，在紫外光照射下有效地产生卤化物自由基和离子。该策略实现了胶体钙钛矿NCs中如CsPbBr向CsPbCl和CsPbBr向CsPbCl的完全晶体转变。交换反应速率可通过B位掺杂剂如Zn和Ce的存在进一步调节。掺杂阳离子部分保留在交换后的钙钛矿NCs中，表明在晶体转变中热力学控制占主导地位。
