Lee Honyeon, Kim Dongjin
Department of Electronic Materials, Devices and Equipment Engineering, Soonchunhyang University, Asan 31538, Korea.
Nanomaterials (Basel). 2022 Oct 13;12(20):3590. doi: 10.3390/nano12203590.
A simulation of quantum dot (QD) energy levels was designed to reproduce a quantum mechanical analytic method based on perturbation theory. A Schrödinger equation describing an electron-hole pair in a QD was solved, in consideration of the heterogeneity of the material parameters of the core and shell. The equation was solved numerically using single-particle basis sets to obtain the eigenstates and energies. This approach reproduced an analytic solution based on perturbation theory, while the calculation was performed using a numerical method. Owing to the effectiveness of the method, QD behavior according to the core diameter and external electric field intensity could be investigated reliably and easily. A 9.2 nm diameter CdSe/ZnS QD with a 4.2 nm diameter core and 2.5 nm thick shell emitted a 530 nm green light, according to an analysis of the effects of core diameter on energy levels. A 4 nm redshift at 5.4×105 V/cm electric field intensity was found while investigating the effects of external electric field on energy levels. These values agree well with previously reported experimental results. In addition to the energy levels and light emission wavelengths, the spatial distributions of wavefunctions were obtained. This analysis method is widely applicable for studying QD characteristics with varying structure and material compositions and should aid the development of high-performance QD technologies.
设计了一种量子点（QD）能级模拟，以重现基于微扰理论的量子力学解析方法。考虑到核与壳材料参数的不均匀性，求解了描述量子点中电子 - 空穴对的薛定谔方程。使用单粒子基组对方程进行数值求解，以获得本征态和能量。这种方法重现了基于微扰理论的解析解，同时使用数值方法进行计算。由于该方法的有效性，可以可靠且轻松地研究量子点根据核直径和外部电场强度的行为。根据对核直径对能级影响的分析，一个直径为9.2 nm、核直径为4.2 nm且壳厚为2.5 nm的CdSe/ZnS量子点发射出530 nm的绿光。在研究外部电场对能级的影响时，发现在电场强度为5.4×105 V/cm时出现了4 nm的红移。这些值与先前报道的实验结果非常吻合。除了能级和发光波长外，还获得了波函数的空间分布。这种分析方法广泛适用于研究具有不同结构和材料组成的量子点特性，并应有助于高性能量子点技术的发展。
