Kajiya Daisuke, Saitow Ken-Ichi
Natural Science Center for Basic Research and Development (N-BARD), Hiroshima University 1-3-1 Kagamiyama Higashi-hiroshima Hiroshima 739-8526 Japan
Department of Chemistry, Graduate School of Science, Hiroshima University 1-3-1 Kagamiyama Higashi-hiroshima Hiroshima 739-8526 Japan.
RSC Adv. 2018 Dec 11;8(72):41299-41307. doi: 10.1039/c8ra08816k. eCollection 2018 Dec 7.
Colloidal silicon nanocrystals (SiNCs) are a promising material for next-generation nanostructured devices. High-stability SiNC solutions are required for practical use as well as studies on the properties of SiNC. Here, we show a solution of SiNCs that was stable for one year without aggregation. The stable solution was synthesized by a facile process, , pulsed laser ablation of a Si wafer in isopropyl alcohol (IPA). The long-term stability was due to a large -potential of -50 mV from a SiNC passivation layer composed of oxygen, hydrogen, and alkane groups, according to the results of eight experiments and theoretical calculations. This passivation layer also resulted in good performance as an additive for a conductive polymer film. Namely, a 5-fold enhancement in carrier density was established by the addition of SiNCs into an organic conductive polymer, poly(3-dodecylthiophene), which is useful for solar cells. Furthermore, it was found that fresh (<1 day) and aged (4 months) SiNCs give the same enhancement. The long-term stability was attributed to a great repulsive energy in IPA, whose value was quantified as a function the distance between SiNCs.
胶体硅纳米晶体（SiNCs）是下一代纳米结构器件的一种很有前景的材料。实际应用以及对SiNC特性的研究都需要高稳定性的SiNC溶液。在此，我们展示了一种SiNCs溶液，其在一年内保持稳定且无聚集现象。这种稳定的溶液是通过一种简便的方法合成的，即脉冲激光烧蚀硅片于异丙醇（IPA）中。根据八项实验和理论计算结果，长期稳定性归因于由氧、氢和烷烃基团组成的SiNC钝化层具有-50 mV的大ζ电位。该钝化层作为导电聚合物薄膜的添加剂也具有良好性能。也就是说，通过将SiNCs添加到有机导电聚合物聚（3 - 十二烷基噻吩）中，载流子密度提高了5倍，这对太阳能电池很有用。此外，发现新鲜（<1天）和老化（4个月）的SiNCs具有相同的增强效果。长期稳定性归因于IPA中存在很大的排斥能，其值被量化为SiNCs之间距离的函数。
