Fang, HP
; Gao, Y (reprint author), Chinese Acad Sci, Shanghai Inst Appl Phys, Div Interfacial Water, Shanghai 201800, Peoples R China.
; Fang, HP
; Gao, Y (reprint author), Chinese Acad Sci, Shanghai Inst Appl Phys, Key Lab Interfacial Phys & Technol, Shanghai 201800, Peoples R China.
文章类型:
期刊论文
英文摘要:
Degradation is the key factor to determine the efficiency and stability of the silicon solar cells, which highly affects their cost and practical performance. Humidity has been well recognized to accelerate the degradation process of the silicon solar cells, but the microscopic mechanism of light-induced degradation in hydrogenated silicon devices at water vapor environment is still elusive. In this paper, combining time-dependent density functional theory with ab initio molecular dynamics (AIMD), we show the water cluster adsorption slightly more elongates the Si-Si bond under illumination compared to the vacuum, which induces electron localization to further greatly facilitate the oxygen molecule absorption and dissociation. This external degradation process is different from the intrinsic degradation mechanisms in hydrogenated silicon devices under light irradiation caused by formation of metastable hydrogen complexes. The transition-state calculations of degradation pathway show the oxidation reaction energy barrier of Si cluster in water vapor environment is lower than that in vacuum, which confirms AIMD observations. Our results not only shed new insight for understanding the microscopic mechanism of light-induced degradation under water vapor, but would also be beneficial for controlling the light-induced silicon degradation of solar cell in real application.
