Coupled electronic states in CdTe quantum dot assemblies fabricated by utilizing chemical bonding between ligands
Coupled electronic states in CdTe quantum dot assemblies fabricated by utilizing chemical bonding between ligands
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利用配体之间的化学键制造的 CdTe 量子点组件中的耦合电子态
DOI：
10.1039/d0nr00194e
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发表时间：
2020
期刊：
影响因子：
6.7
通讯作者：
Kim DaeGwi
中科院分区：
文献类型：
--
作者：
Lee Yong-Shin;Ito Tatsuya;Shimura Kunio;Watanabe Taichi;Bu Hang-Beom;Hyeon-Deuk Kim;Kim DaeGwi
半导体量子点超晶格（QDSL）作为实现高转换效率太阳能电池和高电导率热电元件等新型光电器件的关键材料而备受关注。为了提高基于 QDSL 的光电器件的电荷传输特性，重要的是 QD 结构形成微带，微带是 QD 之间的耦合电子态。较短的量子点间距离和量子点的周期性排列是微带形成的必要条件。在这项研究中，我们使用 N-乙酰基-L 半胱氨酸 (NAC) 短配体封端的 CdTe QD，通过 NAC 之间的化学键合来制造三维 QD 组件。吸收光谱清楚地显示了源自 CdTe QD 组件中相邻 QD 之间波函数耦合的量子共振现象。此外，我们通过检查光致发光 (PL) 光谱的激发能量依赖性和 PL 激发光谱的检测能量依赖性，证明了 CdTe QD 组件中微带的形成。利用NAC之间的化学键合制备QD组件的方法可以应用于所有以NAC作为配体封端的QD。
Semiconductor quantum dot superlattices (QDSLs) have attracted much attention as key materials for realizing new optoelectronic devices such as solar cells with high conversion efficiency and thermoelectric elements with high electrical conductivity. To improve the charge transport properties of QDSL-based optoelectronic devices, it is important that the QD structures form minibands, which are the coupled electronic states between QDs. A shorter inter-QD distance and a periodic arrangement of QDs are the essential conditions for the formation of minibands. In this study, we use CdTe QDs capped with short ligands of N-acetyl-L cysteine (NAC) to fabricate three-dimensional QD assemblies by utilizing chemical bonding between NACs. Absorption spectra clearly display the quantum resonance phenomenon originating from the coupling of the wave functions between the adjacent QDs in CdTe QD assemblies. Furthermore, we demonstrate the formation of minibands in CdTe QD assemblies by examining both, the excitation energy dependence of photoluminescence (PL) spectra and the detection energy dependence of PL excitation spectra. The fabrication method of QD assemblies utilizing chemical bonding between NACs can be applied to all QDs capped with NAC as a ligand.