Department of Chemistry, Texas A&M University, College Station, Texas 77843, USA.
Nanoscale. 2019 Mar 21;11(12):5247-5253. doi: 10.1039/c8nr10439e.
We report the photoinduced post-synthesis method of Mn doping in colloidal perovskite nanocrystals, which can produce Mn-doped CsPbX3 (X = Cl, Br) nanocrystals with preserved size and anisotropic morphology. Photoinduced Mn doping occurs through cation exchange driven by the facile photoinduced halide exchange in dihalomethane (CH2X2, X = Cl, Br) solvent taking advantage of in situ photogeneration of halide ions from the solvent molecules. In the presence of a small amount of Mn acetate dissolved in solvent at sub-micromolar concentration, photoexcitation of the nanocrystals above the bandgap initiates the simultaneous anion and cation exchange. Under the condition of self-anion exchange, the resulting product is only the cation (Mn) doping in the nanocrystal host without changing halide composition, where the extent of doping can be controlled by excitation light intensity. The mild nature of the photoinduced doping also preserves the anisotropic morphology of the nanocrystals. The photoinduced Mn-doping method could be further expanded to other cations providing a versatile means of creating various cation-doped perovskite nanocrystals that are difficult to produce by other means.
我们报告了一种在胶体钙钛矿纳米晶中进行 Mn 掺杂的光后合成方法，该方法可以在保持尺寸和各向异性形貌的情况下制备 Mn 掺杂的 CsPbX3（X = Cl，Br）纳米晶。光诱导 Mn 掺杂是通过二卤甲烷（CH2X2，X = Cl，Br）溶剂中易于发生的光诱导卤化物交换驱动的阳离子交换来实现的，该溶剂利用了从溶剂分子原位光生成的卤化物离子。在存在少量溶解在溶剂中的 Mn 乙酸盐（浓度低于亚微米级）的情况下，纳米晶的带隙以上光激发引发了同时的阴离子和阳离子交换。在自阴离子交换条件下，所得产物仅是纳米晶主体中的阳离子（Mn）掺杂，而不改变卤化物组成，其中掺杂程度可以通过激发光强度来控制。光诱导掺杂的温和性质还保留了纳米晶的各向异性形态。光诱导 Mn 掺杂方法可以进一步扩展到其他阳离子，为通过其他方法难以制备的各种阳离子掺杂钙钛矿纳米晶提供了一种通用的手段。
