Abstract In this study, we investigated the influence of annealing temperature on ultra-small SnO2 quantum dots (SQDs) prepared by a simple chemical reduction process. The structural and optical properties of annealed SQDs were systematically studied by different techniques. Our results show that the crystallinity and average crystallite size of annealed SQDs increased gradually with annealing temperature. The average crystallite size was maintained below 10 nm even for high annealing temperatures. XPS peak fitting analysis yielded information on the presence of mixed ionic states of Sn2+ and Sn4+ in SQDs and further revealed that the number of Sn2+ ions decreased at high temperature. Band-edge shifts were estimated from XPS data. It was possible to shift the bandgap of annealed SQDs from UV to the visible wavelength region, which is likely to have a beneficial impact on many applications of optoelectronic devices.

中文翻译：

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SnO 2 量子点的带隙调谐和 XPS 研究

摘要 在本研究中，我们研究了退火温度对通过简单化学还原工艺制备的超小 SnO2 量子点 (SQD) 的影响。通过不同的技术系统地研究了退火 SQD 的结构和光学特性。我们的结果表明，退火后的 SQD 的结晶度和平均微晶尺寸随着退火温度的升高而逐渐增加。即使在高退火温度下，平均微晶尺寸也保持在 10 nm 以下。XPS 峰拟合分析得出关于 SQD 中 Sn2+ 和 Sn4+ 混合离子状态存在的信息，并进一步揭示 Sn2+ 离子的数量在高温下减少。根据 XPS 数据估计带边偏移。可以将退火的 SQD 的带隙从 UV 转移到可见光波长区域，