Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8573, Japan.
Graduate School of Science and Technology, Gunma University, Kiryu, Gunma 376-8515, Japan.
Nanoscale. 2017 Jan 19;9(3):1193-1200. doi: 10.1039/c6nr08757d.
We demonstrate the emission color change of white-emitting chlorine-terminated silicon nanocrystals (Cl:Si-ncs) to blue-emitting carbon-terminated silicon nanocrystals (C:Si-ncs), together with the enhancement of the luminescence quantum efficiency from 7% to 13%, by post-laser ablation in 1-octene. Such changes of the PL properties are caused by the size reduction of Si-nc and efficient surface passivation by hydrocarbons, resulting from a high reactivity of 1-octene in the laser-ablation and subsequent nanoparticle-formation processes. Furthermore, the second post-laser irradiation of the C:Si-ncs in trichloroethylene reversibly results in the formation of the Cl:Si-ncs. The preparation yield of C:Si-ncs via the post-laser ablation of Cl:Si-ncs is higher than that of C:Si-ncs directly prepared only by the laser ablation of PSi in 1-octene. This high preparation yield is due to the high laser-ablation efficiency in trichloroethylene compared with 1-octene, which is attributed to the low heat loss of the solvent in the laser-ablation process.
我们通过在 1-辛烯中进行激光烧蚀后的处理，证明了发白光的氯终止硅纳米晶体（Cl:Si-ncs）的发射颜色变为发蓝光的碳终止硅纳米晶体（C:Si-ncs），同时发光量子效率从 7%提高到 13%。这种 PL 性质的变化是由 Si-nc 的尺寸减小和碳氢化合物的有效表面钝化引起的，这是由于 1-辛烯在激光烧蚀和随后的纳米颗粒形成过程中的高反应性所致。此外，在三氯乙烯中对 C:Si-ncs 的第二次激光后辐照可逆地导致 Cl:Si-ncs 的形成。通过 Cl:Si-ncs 的激光烧蚀后制备 C:Si-ncs 的产率高于仅通过 1-辛烯中的 PSi 激光烧蚀直接制备 C:Si-ncs 的产率。这种高制备产率归因于与 1-辛烯相比，三氯乙烯中激光烧蚀的效率更高，这是由于激光烧蚀过程中溶剂的热损失较低所致。
