Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
Nanoscale. 2013 Dec 7;5(23):11561-7. doi: 10.1039/c3nr03523a. Epub 2013 Sep 30.
Direct bandgap semiconductors, such as In2O3, Cu2O, and SnO2, have enormous applications in photochemistry, photovoltaics, and optoelectronics. Due to the same parity of conduction and valence bands, the dipole transition is silent in these direct bandgap semiconductors. The low band-to-band transition efficiency prevents them from high intensity light emission or absorption. Here, we report the fabrication of SnO2 quantum dots (QDs) with sizes less than the exciton Bohr radius by a facile "top-down" strategy based on laser fragmentation of SnO in water. The SnO2 QDs shows exciton emission at ∼300 nm with a high quantum yield of ~17%. Amplified spontaneous exciton emission is also achieved from a thin layer of SnO2 QDs dispersed in PEG400 on a quartz substrate. Therefore, we have shown that SnO2 QDs can be a potential luminescent material suitable for the realization of ultraviolet B lasing devices.
直接带隙半导体，如 In2O3、Cu2O 和 SnO2，在光化学、光伏和光电等领域有巨大的应用潜力。由于导带和价带的宇称相同，这些直接带隙半导体中的偶极跃迁是沉默的。低的带-带跃迁效率使得它们无法进行高强度的光发射或吸收。在这里，我们报告了一种通过基于激光在水中对 SnO 进行碎裂的简便“自上而下”策略制备尺寸小于激子玻尔半径的 SnO2 量子点（QDs）。SnO2 QDs 在 ∼300nm 处表现出激子发射，其量子产率高达约 17%。在石英衬底上分散在 PEG400 中的 SnO2 QDs 薄层中也实现了放大的自发激子发射。因此，我们已经表明，SnO2 QDs 可以成为一种潜在的发光材料，适合实现紫外 B 激光器件。
