Cao Zhaopeng, Zhu Jinming, Peng Jun, Meng Nan, Bian Fenggang, Luan Chaoran, Zhang Meng, Li Yan, Yu Kui, Zeng Jianrong
Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, People's Republic of China.
Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201204, People's Republic of China.
J Phys Chem Lett. 2022 May 12;13(18):3983-3989. doi: 10.1021/acs.jpclett.2c00844. Epub 2022 Apr 28.
For those colloidal semiconductor CdSe nanospecies that exhibit sharp optical absorption doublets, different explanations have appeared in the literature regarding their morphological nature and formation, with no consensus reached. Here, we discuss the transformation pathway in two types of CdSe nanoplatelets (NPLs), from NPL-393 to NPL-460, exhibiting absorption doublets at 373/393 and 433/460 nm, respectively. Synchrotron-based small/wide-angle X-ray scattering (SAXS/WAXS) was performed to monitor the transformation associated with the temperature. Combining the results of SAXS/WAXS, optical spectroscopy, and transmission electron microscopy, we propose that the transformation pathway experiences corresponding magic-sized clusters (MSCs), which display similar optical properties but with zero-dimensional structure. From stacked NPL-393 to stacked NPL-460, the transformation goes through sequentially individual NPL-393, MSC-393, MSC-460, and individual NPL-460 at their corresponding characteristic temperature. The present findings provide compelling evidence that both MSCs and their assembled NPLs exhibit similar optical absorption.
对于那些呈现出尖锐光学吸收双峰的胶体半导体CdSe纳米物种，文献中出现了关于它们的形态性质和形成的不同解释，但尚未达成共识。在此，我们讨论了两种类型的CdSe纳米片（NPLs）从NPL - 393到NPL - 460的转变途径，它们分别在373/393和433/460 nm处呈现吸收双峰。利用基于同步加速器的小角/广角X射线散射（SAXS/WAXS）来监测与温度相关的转变。结合SAXS/WAXS、光谱学和透射电子显微镜的结果，我们提出转变途径经历了相应的魔法尺寸团簇（MSCs），其具有相似的光学性质但为零维结构。从堆叠的NPL - 393到堆叠的NPL - 460，转变在其相应的特征温度下依次经过单个NPL - 393、MSC - 393、MSC - 460和单个NPL - 460。目前的研究结果提供了令人信服的证据，表明MSCs及其组装的NPLs都表现出相似的光学吸收。
