Unassisted Water Splitting Exceeding 9% Solar-to-Hydrogen Conversion Efficiency by Cu(In, Ga)(S, Se)2 Photocathode with Modified Surface Band Structure and Halide Perovskite Solar Cell

• Published in: ACS applied energy materials Vol. 3; no. 3; pp. 2296 - 2303
• Main Authors: Koo, Bonhyeong, Kim, Daehan, Boonmongkolras, Passarut, Pae, Seong Ryul, Byun, Segi, Kim, Jekyung, Lee, June Hyuk, Kim, Dong Hoe, Kim, Suncheul, Ahn, Byung Tae, Nam, Sung-Wook, Shin, Byungha
• Format: Journal Article
• Language: English
• Published: American Chemical Society 23.03.2020
• Subjects: surface band bending; solar-to-hydrogen; perovskite solar cell; unassisted solar water splitting; Cu(In, Ga)(S, Se)2 photocathode
• ISSN: 2574-0962; 2574-0962
• DOI: 10.1021/acsaem.9b02387

By introducing ZnS between Cu­(In, Ga)­(S,Se)2 (CIGS) and the CdS, we greatly improved the photoelectrochemical (PEC) performance of the CIGS photocathode for hydrogen evolution. Chemical and structural analysis reveals that the enhanced performance is due to additional band bending driven by in-diffusion of Zn into the CIGS and suppression of nonradiative recombination. The improved onset potential of CIGS photocathode was exploited by building a tandem device with a perovskite absorber for bias-free water splitting. A PEC device with a solar-to-hydrogen conversion efficiency exceeding 9% (the highest among PEC cells including a CIGS photocathode) with a stable operation of 6.5 h is demonstrated.