Chen Zhao, Chen Xiaohan, Xiao Yuan, Ren Shuming, Li Yang
Department of Basic Chemistry, School of Pharmacy, Zunyi Medical University, Zunyi, 563000, P. R. China.
School of Applied Physics and Materials, Wuyi University, Jiangmen, 529020, P. R. China.
Adv Sci (Weinh). 2025 Jun 23:e05737. doi: 10.1002/advs.202505737.
The bottom-up design of chemical structure affords 0D nanocrystals (NCs) with tunable band structures and unexpected optical properties. Herein, an example of alloyed quantum shell (QS) is demonstrated by tailoring the chemical compositions in its core/shell structure. In the CdZnSe/ZnSeS/CdSeS/CdS (C/S/S/S, in which C is the CdZnSe core and S represents the shells) structure, there is an intriguing metamorphosis from quantum dot (QD) to QS (that is, C and C/S belong to QDs, meanwhile C/S/S and C/S/S/S are in the QS regime). Due to uniform morphology, perfect nanostructure, negligible defects, and unique energy level alignment, the C/S/S/S QS exhibits a high photoluminescence quantum yield of 90.9%, an ultra-long fluorescence lifetime of 215.2 ns, and a slow radiative transition rate. It enables QS-based light-emitting diodes (QS-LEDs) with the state-of-the-art performance, such as high external quantum efficiency (EQE of 22.16%) and excellent stability. Meanwhile, the investigation of charge carrier dynamics reveals the difference between the QD- and QS-LEDs, showing that the charge carriers inside the QS-LEDs need more time to recombine with each other. Based on these findings, this study believes that the emerging QSs can be attractive and efficient light-emitting materials used in lighting and displays.
化学结构的自下而上设计可提供具有可调谐能带结构和意外光学特性的零维纳米晶体（NCs）。在此，通过调整其核/壳结构中的化学成分，展示了一种合金量子壳（QS）的示例。在CdZnSe/ZnSeS/CdSeS/CdS（C/S/S/S，其中C是CdZnSe核，S代表壳层）结构中，存在从量子点（QD）到量子壳（QS）的有趣转变（即，C和C/S属于量子点，同时C/S/S和C/S/S/S处于量子壳状态）。由于形态均匀、纳米结构完美、缺陷可忽略不计以及独特的能级排列，C/S/S/S量子壳表现出90.9%的高光致发光量子产率、215.2 ns的超长荧光寿命和缓慢的辐射跃迁速率。它使得基于量子壳的发光二极管（QS-LEDs）具有诸如高外部量子效率（EQE为22.16%）和出色稳定性等先进性能。同时，对电荷载流子动力学的研究揭示了量子点发光二极管和量子壳发光二极管之间的差异，表明量子壳发光二极管内部的电荷载流子需要更多时间相互复合。基于这些发现，本研究认为新兴量子壳可以成为用于照明和显示的有吸引力且高效的发光材料。
