Han Xiao, Zhao Qi, Yan Xiaodan, Meng Ting, He Jinlu
College of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010021, P. R. China.
Phys Chem Chem Phys. 2023 Dec 6;25(47):32622-32631. doi: 10.1039/d3cp05217f.
By performing nonadiabatic molecular dynamics combined with time-domain density functional theory, we have explored the effects of the charge density of a sulfur vacancy on charge trapping and recombination in antimony trisulfide (SbS). The simulations demonstrate that, compared to an antimony vacancy, the sulfur vacancy generates a high charge density trap state within the band gap. This state acts as the recombination center and provides new channels for charge carrier relaxation. Filling the sulfur vacancy with electron donors elevates the defect state to the Fermi level due to the introduced extra electrons. In contrast, the electron acceptor lowers the charge density of the sulfur vacancy by capturing its local electrons, eliminating the charge recombination center and extending the photo-generated charge carrier lifetime. Additionally, compared with electron injection, hole injection can also decrease the charge density of the trap state neutralizing its local electronic states, eliminate the trap state within the band gap, and suppress nonradiative electron-hole recombination. This study is expected to shed new light on the blocking recombination centers and provide valuable insights into the design of high-performance solar cells.
通过结合时域密度泛函理论进行非绝热分子动力学模拟，我们研究了硫空位的电荷密度对三硫化锑（SbS）中电荷俘获和复合的影响。模拟结果表明，与锑空位相比，硫空位在带隙内产生了一个高电荷密度陷阱态。这个态充当复合中心，并为电荷载流子弛豫提供了新的通道。用电子供体填充硫空位会由于引入的额外电子而将缺陷态提升到费米能级。相反，电子受体通过捕获硫空位的局域电子降低其电荷密度，消除电荷复合中心并延长光生电荷载流子寿命。此外，与电子注入相比，空穴注入也可以降低陷阱态的电荷密度，中和其局域电子态，消除带隙内的陷阱态，并抑制非辐射电子 - 空穴复合。这项研究有望为阻断复合中心提供新的思路，并为高性能太阳能电池的设计提供有价值的见解。
