Kim, Byungwoo Park, Gi-Soon Chae, Sang Youn Kim, Min Kyu Oh, Hyung-Suk Hwang, Yun Jeong Kim, Woong Min, Byoung Koun 2024-01-19T23:03:40Z 2024-01-19T23:03:40Z 2021-09-03 2018-03-26 2045-2322 https://pubs.kist.re.kr/handle/201004/121581 Surface modification of a Cu(In,Ga)(S,Se)(2) (CIGSSe) absorber layer is commonly required to obtain high performance CIGSSe photocathodes. However, surface modifications can cause disadvantages such as optical loss, low stability, the use of toxic substances and an increase in complexity. In this work, we demonstrate that a double-graded bandgap structure (top-high, middle-low and bottom-high bandgaps) can achieve high performance in bare CIGSSe photocathodes without any surface modifications via a hetero-materials overlayer that have been fabricated in a cost-effective solution process. We used two kinds of CIGSSe film produced by different precursor solutions consisting of different solvents and binder materials, and both revealed a double-graded bandgap structure composed of an S-rich top layer, Ga- and S-poor middle layer and S-and Ga-rich bottom layer. The bare CIGSSe photocathode without surface modification exhibited a high photoelectrochemical activity of similar to 6 mA.cm(-2) at 0 V vs. RHE and similar to 22 mA.cm(-2) at -0.27 V vs. RHE, depending on the solution properties used in the CIGSSe film preparation. The incorporation of a Pt catalyst was found to further increase their PEC activity to similar to 26 mA.cm(-2) at -0.16 V vs. RHE. English NATURE PUBLISHING GROUP THIN-FILM WATER SURFACE CELLS PERFORMANCE EVOLUTION SULFURIZATION CHALCOPYRITE ENHANCEMENT REDUCTION A highly efficient Cu(In,Ga)(S,Se)(2) photocathode without a hetero-materials overlayer for solar-hydrogen production Article 10.1038/s41598-018-22827-3 1 SCIENTIFIC REPORTS, v.8 SCIENTIFIC REPORTS 8 scie scopus 000428234100003 2-s2.0-85044532063 Multidisciplinary Sciences Science & Technology - Other Topics Article THIN-FILM WATER SURFACE CELLS PERFORMANCE EVOLUTION SULFURIZATION CHALCOPYRITE ENHANCEMENT REDUCTION CIGS solar hydrogen photocathode