Room-Temperature Chemical Solution Treatment for Flexible ZnS(O,OH)/Cu(In,Ga)Se2 Solar Cell: Improvements in Interface Properties and Metastability

详细信息    查看全文

• 作者：Wei-Hao Ho ; Chia-Hao Hsu ; Tzu-Hsuan Yeh ; Yu-Han Chang ; Shih-Yuan Wei ; Tzu-Ying Lin ; Chih-Huang Lai
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：March 16, 2016
• 年：2016
• 卷：8
• 期：10
• 页码：6709-6717
• 全文大小：570K
• ISSN：1944-8252

文摘

We demonstrate an effective room-temperature chemical solution treatment, by using thioacetamide (S treatment) or thioacetamide-InCl₃ (In–S treatment) solution, on Cu(In,Ga)Se₂ (CIGSe) surface to engineer the ZnS(O,OH)/CIGSe interface and junction quality, leading to enhanced efficiency and minimized metastability of flexible solar cells. The control device without treatment reveals a relatively low efficiency of 8.15%, which is significantly improved to 9.74% by In–S treatment, and 10.39% by S treatment. Results of X-ray photoelectron spectroscopy suggest that S is incorporated into CIGSe surface forming CIGSSe by S treatment, whereas a thin In–S layer is formed on CIGSe surface by In–S treatment with reduced amount of S diffusing into CIGSe. PL spectra and TRPL lifetime further reveal that S incorporation into CIGS surface may substitute the O_Se and/or directly occupy the vacant anion site (V_Se), resulting in the effective passivation of the recombination centers at CIGSe surface. Moreover, reducing the concentrations of V_Se may thereby decrease the density of (V_Cu–V_Se) acceptors, which can minimize the metastability of ZnS(O,OH)/CIGSe solar cells. With S treatment, the light soaking (LS) time of ZnS(O,OH)/CIGSe device is reduced approximately to one-half of control one. Our approach can be potentially applied for alternative Cd-free buffer layers to achieve high efficiency and low metastability.