College of Material Engineering, Shanghai University of Engineering Science, 333 Long Teng Road, Shanghai 201620, People's Republic of China.
Nanotechnology. 2019 Jan 4;30(1):015705. doi: 10.1088/1361-6528/aae67c. Epub 2018 Oct 26.
Stable luminescent colloidal silicon (Si) nanocrystals (NCs) with sufficient surface protection are prepared through femtosecond laser ablation in organic solvent containing diverse concentrations of HF solution. The average size of Si NCs shows the decreasing tendency from 6.5 to 2.7 nm when the concentration of HF varies from 0 to 11.1 vol% (volume ratio). In line with the structural evolution, UV-visible absorption, photoluminescence (PL) excitation spectra, and time-resolved PL, we propose that room temperature blue emission peaks at 412 and 440 nm originate from alkyl-related radiative recombination centers. The enhanced PL quantum yield of colloidal Si NCs from 16.3% to 76.5% has been attributed to the effective passivation and suppression of non-radiative defect centers with increasing HF concentration from 0 to 11.1 vol%.
稳定的发光胶体硅（Si）纳米晶体（NCs）通过在含有不同浓度 HF 溶液的有机溶剂中进行飞秒激光烧蚀制备得到，具有足够的表面保护。当 HF 的浓度从 0 变化到 11.1 体积%（体积比）时，Si NCs 的平均尺寸呈现出从 6.5nm 减小到 2.7nm 的趋势。与结构演化一致，紫外-可见吸收、光致发光（PL）激发光谱和时间分辨 PL 表明，室温下 412nm 和 440nm 的蓝发射峰源于与烷基相关的辐射复合中心。随着 HF 浓度从 0 增加到 11.1 体积%，胶体 Si NCs 的 PL 量子产率从 16.3%提高到 76.5%，这归因于非辐射缺陷中心的有效钝化和抑制。
