Due to the quantum size effect and other unique photoelectric properties, quantum dots (QDs) have attracted tremendous interest in nanoscience, leading a lot of milestone works. Meantime, the scope and scientific connotation of QDs are constantly expanding, which demonstrated amazing development vitality. Besides the well-developed Cd-containing II–VI semiconductors, QDs of environmentally friendly I–III–VI (I = Cu, Ag; III = Ga, In; VI = S, Se) chalcogenides have been a hot spot in the QDs family, which are different from traditional II–VI QDs in terms of multi-composition, complex defect structure, synthetic chemistry and optical properties, bringing a series of new laws, new phenomena and new challenges. The composition of I–III–VI chalcogenides and their solid solutions can be adjusted within a very large range while the anion framework remains stable, giving them excellent capability of photoelectric property manipulation. The important features of I–III–VI QDs include wide-range bandgap tuning, large Stokes shift and long photoluminescence (PL) lifetime, which are crucial for biological, optoelectronic and energy applications. This is due to the coexistence of two or more metal cations leading to a large number of intrinsic defects within the crystal lattice also known as deep-donor-acceptor states, besides the commonly observed surface defects in all QDs. However, a profound understanding of their structure and optoelectronic properties remains a huge challenge with many key issues unclear. On one hand, the achievements and experience of traditional QD research are expected to provide vital value for further development of I–III–VI QDs. On the other hand, the understanding of the emerging new QDs, such as carbon and other 2D materials, are even more challenging because of the dramatically different composition and structure from II–VI semiconductors. For this, I–III–VI QDs, as a close relative to II–VI QDs but with much more complex composition and structure variation, provide a great opportunity as a gradual bridge to make up the big gap between traditional QDs and emerging new QDs, such as carbon dots. Here, we hope to compare the research progress of I–III–VI QDs and II–VI QDs, in an effort to comprehensively understand their structure, synthetic chemistry, optical electronic and photocatalytic properties. We further give insights on the key potential issues of I–III–VI QDs from the perspective of bridging between traditional QDs and emerging carbon dots, especially the profound principles behind synthetic chemistry, PL mechanism and optoelectronic applications.

中文翻译：

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I-III-VI 量子点的光电和光催化特性：传统和新兴新型量子点之间的桥梁

由于量子尺寸效应和其他独特的光电特性，量子点（QDs）引起了纳米科学的极大兴趣，引领了许多里程碑式的工作。同时，量子点的范围和科学内涵也在不断扩大，展现出惊人的发展活力。除了成熟的含 Cd 的 II-VI 半导体外，环境友好的 I-III-VI（I = Cu，Ag；III = Ga，In；VI = S，Se）硫族化物的 QD 一直是 QD 中的热点家族，它在多组分、复杂缺陷结构、合成化学和光学性质方面不同于传统的 II-VI QD，带来了一系列新规律、新现象和新挑战。I-III-VI硫属化物及其固溶体的组成可以在非常大的范围内调整，同时阴离子骨架保持稳定，使其具有优异的光电性能操纵能力。I-III-VI QD 的重要特征包括宽范围带隙调谐、大斯托克斯位移和长光致发光 (PL) 寿命，这对于生物、光电和能源应用至关重要。这是由于两种或多种金属阳离子的共存导致晶格内的大量本征缺陷，也称为深供体受体状态，除了所有 QD 中常见的表面缺陷。然而，对其结构和光电特性的深刻理解仍然是一个巨大的挑战，许多关键问题尚不清楚。一方面，传统量子点研究的成果和经验有望为 I-III-VI 量子点的进一步发展提供重要价值。另一方面，由于与 II-VI 半导体的成分和结构截然不同，因此对新兴的新型 QD（例如碳和其他 2D 材料）的理解更具挑战性。为此，I-III-VI QDs 作为与 II-VI QDs 的近亲但具有更复杂的组成和结构变化，提供了一个很好的机会，作为一个渐进的桥梁来弥补传统 QDs 和新兴的新 QDs 之间的巨大差距，例如碳点。在这里，我们希望比较 I-III-VI 量子点和 II-VI 量子点的研究进展，以期全面了解它们的结构、合成化学、光学电子和光催化性能。