Zhu Jinming, Cao Zhaopeng, Zhu Yongcheng, Rowell Nelson, Li Yan, Wang Shanling, Zhang Chunchun, Jiang Gang, Zhang Meng, Zeng Jianrong, Yu Kui
Institute of Atomic and Molecular Physics, Sichuan University, Chengdu, Sichuan, 610065, P. R. China.
Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201800, P. R. China.
Angew Chem Int Ed Engl. 2021 Sep 6;60(37):20358-20365. doi: 10.1002/anie.202104986. Epub 2021 Jun 21.
Divergent interpretations have appeared in the literature regarding the structural nature and evolutionary behavior for photoluminescent CdSe nanospecies with sharp doublets in optical absorption. We report a comprehensive description of the transformation pathway from one CdSe nanospecies displaying an absorption doublet at 373/393 nm to another species with a doublet at 433/460 nm. These two nanospecies are zero-dimensional (0D) magic-size clusters (MSCs) with 3D quantum confinement, and are labeled dMSC-393 and dMSC-460, respectively. Synchrotron-based small-angle X-ray scattering (SAXS) returns a radius of gyration of 0.92 nm for dMSC-393 and 1.14 nm for dMSC-460, and indicates that both types are disc shaped with the exponent of the SAXS form factor equal to 2.1. The MSCs develop from their unique counterpart precursor compounds (PCs), which are labeled PC-393 and PC-460, respectively. For the dMSC-393 to dMSC-460 transformation, the proposed PC-enabled pathway is comprised of three key steps, dMSC-393 to PC-393 (Step 1), PC-393 to PC-460 (Step 2 involving monomer addition), and PC-460 to dMSC-460 (Step 3). The present study provides a framework for understanding the PC-based evolution of MSCs and how PCs enable transformations between MSCs.
关于具有尖锐双峰光吸收的光致发光CdSe纳米物种的结构性质和演化行为，文献中出现了不同的解释。我们报告了从一种在373/393 nm处显示吸收双峰的CdSe纳米物种到另一种在433/460 nm处具有双峰的物种的转变途径的全面描述。这两种纳米物种是具有三维量子限制的零维(0D) 魔尺寸团簇 (MSC)，分别标记为dMSC-393和dMSC-460。基于同步加速器的小角X射线散射 (SAXS) 得出dMSC-393的回转半径为0.92 nm，dMSC-460的回转半径为1.14 nm，并表明这两种类型均为盘状，SAXS形状因子的指数等于2.1。这些MSC由其独特的对应前驱体化合物 (PC) 形成，分别标记为PC-393和PC-460。对于从dMSC-393到dMSC-460的转变，所提出的基于PC的途径包括三个关键步骤，即从dMSC-393到PC-393（步骤1）、从PC-393到PC-460（步骤2涉及单体添加）以及从PC-460到dMSC-460（步骤3）。本研究为理解基于PC的MSC演化以及PC如何实现MSC之间的转变提供了一个框架。
