Department of Chemistry, James Franck Institute, and Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, United States.
Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439, United States.
Nano Lett. 2022 Aug 24;22(16):6545-6552. doi: 10.1021/acs.nanolett.2c01699. Epub 2022 Aug 11.
The goal of this work is to determine the kinetic factors that govern isovalent cation exchange in III-V colloidal quantum dots using molten salts as the solvent and cation source. We focus on the reactions of InP + GaI→ InGaP and InAs + GaI→ InGaAs to create technologically important ternary III-V phases. We find that the molten salt reaction medium causes the transformation of nearly spherical InP nanocrystals to tetrahedron-shaped InGaP nanocrystals. Furthermore, we determine that the activation energy for the cation exchange reaction is 0.9 eV for incorporation of Ga into InP and 1.2 eV for incorporation of Ga into InAs, both much lower than the measured values in bulk semiconductors. Next, we use powder XRD simulations to constrain our understanding of the structure of the InGaP nanocrystals. Together our results reveal several important features of molten salt-mediated cation exchange and provide guidance for future development of these materials.
这项工作的目标是利用熔融盐作为溶剂和阳离子源，确定 III-V 胶体量子点中同价阳离子交换的动力学因素。我们专注于 InP + GaI→ InGaP 和 InAs + GaI→ InGaAs 的反应，以生成具有重要技术意义的三元 III-V 相。我们发现，熔融盐反应介质导致近乎球形的 InP 纳米晶转化为四面体形状的 InGaP 纳米晶。此外，我们确定 Ga 掺入 InP 和 Ga 掺入 InAs 的阳离子交换反应的激活能分别为 0.9 eV 和 1.2 eV，均远低于体半导体中的测量值。接下来，我们使用粉末 XRD 模拟来约束我们对 InGaP 纳米晶结构的理解。我们的结果共同揭示了熔融盐介导的阳离子交换的几个重要特征，并为这些材料的未来发展提供了指导。
