Wei Lijing, Li Feng, Pang Shaoyuan, Wang Yinglong, Guo Jianxin, Chen Jianhui
School of Computer and Information Engineering, Hebei Finance University, Baoding, Hebei 071051, P. R. China.
Key Laboratory of Optic-Electronic Information Materials of Hebei Province, College of Physics Science and Technology, Hebei University, Baoding, 071002, P. R. China.
Phys Chem Chem Phys. 2022 May 11;24(18):11169-11174. doi: 10.1039/d2cp00572g.
Highly effective defect passivation schemes are very important for the improvement of Si nanowire (SiNW) performances, because large numbers of outer-shell-defect states are caused by the high surface-to-volume ratios of nanowires. In this work, a polymer that can be fabricated by a simple, vacuum-free method at low temperatures, Nafion, was studied for the SiNW outer-shell defect passivation using first-principles calculations. Based on adsorption energy calculations, it was found that the Nafion molecule could firmly adsorb on the surfaces of SiNWs along the 〈112〉 direction. The Nafion-passivated SiNW outer-shell exhibited high stability to a chemical environment. Herein, the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) were confined to the center of the SiNW due to being wrapped by the Nafion. The Nafion-passivated SiNWs exhibited an equivalent quantum confinement effect and a larger absorption coefficient compared with the H-passivated SiNWs. This work demonstrated a passivation strategy of SiNW shell defects using functional groups.
高效的缺陷钝化方案对于提高硅纳米线（SiNW）的性能非常重要，因为纳米线的高表面积与体积比会导致大量的外壳缺陷态。在这项工作中，使用第一性原理计算研究了一种可以通过简单的低温无真空方法制备的聚合物Nafion，用于SiNW外壳缺陷的钝化。基于吸附能计算，发现Nafion分子可以沿〈112〉方向牢固地吸附在SiNW的表面。Nafion钝化的SiNW外壳对化学环境表现出高稳定性。在此，由于被Nafion包裹，最高占据分子轨道（HOMO）和最低未占据分子轨道（LUMO）被限制在SiNW的中心。与H钝化的SiNW相比，Nafion钝化的SiNW表现出等效的量子限制效应和更大的吸收系数。这项工作展示了一种使用官能团对SiNW外壳缺陷进行钝化的策略。
