Han Pingping, Yang Xiaowei, Du Tingli, Zhao Jijun, Zhou Si
Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024, China.
Guangdong Basic Research Center of Excellence for Structure and Fundamental Interactions of Matter, Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, School of Physics, South China Normal University, Guangzhou 510006, China.
J Phys Chem Lett. 2024 Jul 25;15(29):7502-7508. doi: 10.1021/acs.jpclett.4c01687. Epub 2024 Jul 17.
Semiconductor magic-size clusters (MSCs), lying in the local minima of the potential landscape, are important intermediates that emerge during the synthesis of colloidal quantum dots. They have definite geometrical and electronic structures, thus serving as atomically precise building blocks for assembling supramolecular structures and devices with unprecedented functionalities. Here we report the intrinsic chiroptical activity in the magic-size cadmium and zinc chalcogenide clusters with magic numbers of 13, 33, and 34 possessing unique core-shell structures. They are responsive to circularly polarized light from the ultraviolet to visible region, with size-tunable energy gap, absorption wavelength, and excitonic characteristics. The origin of the chiroptical activity and the evolution of excitonic states with magic size are disclosed by time-dependent density functional theory calculations within a correlated electron-hole picture. This molecular-level understanding of the photophysical properties of group II-VI MSCs provides essential guidelines for utilizing them for chiral optoelectronics and photonics.
半导体幻数团簇（MSCs）处于势能面的局部极小值，是胶体量子点合成过程中出现的重要中间体。它们具有确定的几何和电子结构，因此可作为原子精确的构建单元，用于组装具有前所未有的功能的超分子结构和器件。在此，我们报道了具有13、33和34等幻数且拥有独特核壳结构的硫族镉和锌幻数团簇的固有圆二色活性。它们对从紫外到可见光区域的圆偏振光有响应，具有尺寸可调的能隙、吸收波长和激子特性。通过在相关电子-空穴图像中的含时密度泛函理论计算，揭示了圆二色活性的起源以及激子态随幻数尺寸的演变。这种对II-VI族MSCs光物理性质的分子水平理解为将它们用于手性光电子学和光子学提供了重要指导。
