Tailoring Photoelectrochemical Performance and Stability of Cu(In,Ga)Se2 Photocathode via TiO2-Coupled Buffer Layers

详细信息    查看全文

• 作者：Bonhyeong Koo ; Sung-Wook Nam ; Richard Haight ; Suncheul Kim ; Seungtaeg Oh ; Minhyung Cho ; Jihun Oh ; Jeong Yong Lee ; Byung Tae Ahn ; Byungha Shin
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2017
• 出版时间：February 15, 2017
• 年：2017
• 卷：9
• 期：6
• 页码：5279-5287
• 全文大小：722K
• ISSN：1944-8252

文摘

We report on the photoelectrochemical (PEC) performance and stability of Cu(In,Ga)Se₂ (CIGS)-based photocathodes for photocatalytic hydrogen evolution from water. Various functional overlayers, such as CdS, TiO₂, Zn_xSn_yO_z, and a combination of the aforementioned, were applied on the CIGS to improve the performance and stability. We identified that the insertion of TiO₂ overlayer on p-CIGS/n-buffer layers significantly improves the PEC performance. A multilayered photocathode consisting of CIGS/CdS/TiO₂/Pt exhibited the best current–potential characteristics among the tested photocathodes, which demonstrates a power-saved efficiency of 2.63%. However, repeated linear sweep voltammetry resulted in degradation of performance. In this regard, we focused on the PEC durability issues through in-depth chemical characterization that revealed the degradation was attributed to atomic redistribution of elements constituting the photocathode, namely, in-diffusion of Pt catalysts, out-diffusion of elements from the CIGS, and removal of the metal-oxide layers; the best-performing CIGS/CdS/TiO₂/Pt photocathode retained its initial performance until the TiO₂ overlayer was removed. It was also found that the durability of CIGS photocathodes with a TiO₂-coated metal-oxide buffer layer such as Zn_xSn_yO_z was better than those with a TiO₂-coated CdS, and the degradation mechanism was different, suggesting that the stability of a CIGS-based photocathode can be improved by careful design of the structure.