Popelář Tomáš, Matějka Filip, Kopenec Jakub, Morselli Giacomo, Ceroni Paola, Kůsová Kateřina
Institute of Physics of the CAS v.v.i., Cukrovarnická 10 162 00 Prague 6 Czechia
University of Chemistry and Technology Technická 5 166 28 Praha 6 Czechia.
Nanoscale Adv. 2024 Apr 9;6(10):2644-2655. doi: 10.1039/d3na01031g. eCollection 2024 May 14.
Silicon quantum dots (QDs) are a promising non-toxic alternative to the already well-developed platform of light-emitting semiconductor QDs based on III-V and II-VI materials. Oxidized SiQDs or those surface-terminated with long alkyl chains typically feature long-lived orange-red photoluminescence originating in quantum-confined core states. However, sometimes an additional short-lived PL band, whose mechanism is still highly debated, is reported. Here, we perform a detailed study of the room-temperature PL of SiQDs using samples covering three main fabrication techniques. We find evidence for the presence of only one set of radiative processes in addition to the typical long-lived PL. Moreover, we experimentally determine the ratio between the short- and long-lived PL component, obtaining a wide range of values (0.003 - 0.1) depending on the type of sample. In accordance with an already published report, we observe a tendency of SiQDs with stronger short-lived PL to have lower external quantum yield. We explain this trend using a model of the optical performance of an ensemble of QDs with widely varying optical characteristics through a mechanism we call .
硅量子点（QDs）是一种很有前景的无毒替代品，可替代基于III-V族和II-VI族材料的、已经发展成熟的发光半导体量子点平台。氧化的硅量子点或表面被长烷基链封端的硅量子点通常具有源自量子限制核心态的长寿命橙红色光致发光特性。然而，有时会报道存在一个额外的短寿命光致发光带，其机制仍存在激烈争论。在这里，我们使用涵盖三种主要制备技术的样品，对硅量子点的室温光致发光进行了详细研究。我们发现，除了典型的长寿命光致发光外，只存在一组辐射过程的证据。此外，我们通过实验确定了短寿命和长寿命光致发光成分之间的比例，根据样品类型获得了广泛的值（0.003 - 0.1）。与已发表的报告一致，我们观察到具有较强短寿命光致发光的硅量子点有较低的外量子产率的趋势。我们通过一种我们称之为的机制，使用具有广泛不同光学特性的量子点集合的光学性能模型来解释这种趋势。
