Coherent InP/ZnS core@shell quantum dots with narrow-band green emissions
Coherent InP/ZnS core@shell quantum dots with narrow-band green emissions
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DOI：
10.1039/d2nr02071h
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发表时间：
2022-07-04
期刊：
影响因子：
6.7
通讯作者：
Shirahata, Naoto
中科院分区：
文献类型：
--
作者：
Nemoto, Kazuhiro;Watanabe, Junpei;Shirahata, Naoto
本文首次报道了硫化锌（ZnS）在胶体磷化铟（InP）量子点（QD）上的相干生长，得到了单晶格常数为0.563 nm的InP/ZnS核壳结构。与锌共混（立方）InP块体晶体相比，核心量子点的晶格压缩了4.1%。相比之下，当壳层厚度小于等于0.81 nm，且核心量子点直径小于2.64 nm时，壳层晶格相对于体积较大的ZnS晶体膨胀4.1%。在这些条件下，核心量子点的带隙增大，导致吸收光谱和光致发光光谱发生蓝移。PL峰以523 nm为中心。此外，基于增强的量子约束效应，PL的量子产率提高了70%，PL的带宽缩小到36 nm。研究了光致发光性能的温度依赖性，讨论了核壳晶格相干性对光致发光性能的影响。
We report, for the first time, that the coherent growth of zinc sulfide (ZnS) on a colloidal indium phosphide (InP) quantum dot (QD) yields a InP/ZnS core/shell structure with a single lattice constant of 0.563 nm. Compared to the bulk crystal of zinc-blend (cubic) InP, the lattice of the core QD is compressed by 4.1%. In contrast, the lattice of the shell expands by 4.1% relative to the bulky ZnS crystal throughout the core/shell QD if the shell is thinner than or equal to 0.81 nm and the diameter of the core QD is smaller than 2.64 nm. Under these conditions, the bandgap of the core QD increases, resulting in a blueshift of absorption and photoluminescence (PL) spectra. The PL peak is centered at 523 nm. Furthermore, the PL quantum yield is enhanced up to 70% and the PL bandwidth narrows to 36 nm based on the strengthened quantum confinement effect. The temperature dependence of the PL properties is investigated to discuss the effect of the core/shell lattice coherency on the improved PL performances.