Despite the recent great interest in ternary AgInS₂ quantum dots (QDs), theoretical studies on fundamental features such as size-dependent optical properties and surface defect characteristics have been relatively scarce. This is due to the practical difficulty of performing electronic structure calculations that take into account not only the structural complexity of ternary AgInS₂ QDs compared to conventional binary QDs, but also the complex organic ligands that cover the inorganic crystalline surface. In this study, we theoretically explored the optical properties of AgInS₂ QDs from the cluster structures by introducing a simple ligand model that mimics the role of real ligands for surface passivation. First, an analytical equation is presented that relates size and bandgap, which indicates that the quantum confinement effect of AgInS₂ QDs is smaller than that of binary InP QDs. Through electronic structure calculations of surface defects, it was found that surface In defects alone or in combination with surface S defects significantly inhibit radiative transition properties, whereas surface Ag defects do not adversely affect its optical properties. Furthermore, synthesis and measurement of AgInS₂ QDs validate the bandgap equation and surface defect characteristics.

中文翻译：

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探索 AgInS2 量子点尺寸和表面缺陷影响的光学特性：基于简单配体模型的理论研究


尽管最近人们对三元 AgInS₂ 量子点 （QD） 产生了浓厚的兴趣，但关于尺寸依赖性光学特性和表面缺陷特性等基本特征的理论研究相对较少。这是因为进行电子结构计算的实际难度，不仅要考虑三元 AgInS₂ QD 与传统二元 QD 相比的结构复杂性，还要考虑覆盖无机晶体表面的复杂有机配体。在这项研究中，我们通过引入一个简单的配体模型，从理论上探索了AgInS₂ QDs在团簇结构中的光学特性，该模型模拟了真实配体在表面钝化中的作用。首先，提出了一个与尺寸和带隙相关的解析方程，这表明 AgInS₂ QD 的量子限制效应小于二元 InP QD 的量子限制效应。通过表面缺陷的电子结构计算，发现表面 In 缺陷单独或与表面 S 缺陷结合显着抑制了辐射过渡特性，而表面 Ag 缺陷不会对其光学特性产生不利影响。此外，AgInS₂ QD 的合成和测量验证了带隙方程和表面缺陷特性。