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

Abstract

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.

Water Splitting: From Electrode to Green Energy System

“…Compared to Si solar cell, the outstanding advantage of CIGS is that the band gap energy can be modulated to effectively absorb the solar spectrum, so it is also widely used to achieve water splitting [129][130][131]. For purpose of overcoming the problem of low energy to drive overall water splitting, connected series into a monolithic device can be Fig.…”

NiMoV and NiO-based catalysts for efficient solar-driven water splitting using thermally integrated photovoltaics in a scalable approach

“…Both catalytic current and gas volume measurement approaches were used for the determination of efficiency. The performance is lower than tandem PV approaches using concentrated solar light and precious catalysts ( Liu et al., 2017 ; Tembhurne et al., 2019 ) but compares favorably with recent stand-alone water splitting approaches with smaller areas with 6.7% for a monolithic perovskite device ( Liang et al., 2020 ) without precious catalysts and a recent CIGS-perovskite approach with precious catalyst showing 9% efficiency using a wired approach ( Koo et al., 2020 ). Several of these approaches, however, are only shown for significantly smaller areas where the efficiencies may not be sustained upon up-scaling in cell or system size.…”

Recent Progress in Designing Halide-Perovskite-Based System for the Photocatalytic Applications

“…The device shows an onset potential of 0.66 V RHE . Combined with IrO x anode on a lead halide perovskite solar cell, a remarkable solar-to-hydrogen efficiency of 9.04% and stability for over 6.5 h can be achieved (Koo et al, 2020 ). Ahmad et al designed a Cs-FA-MA triple-cation-based perovskite photocathode with Al-doped ZnO protective layer for HER.…”

“…The device shows an onset potential of 0.66 V RHE . Combined with IrO x anode on a lead halide perovskite solar cell, a remarkable solar-to-hydrogen efficiency of 9.04% and stability for over 6.5 h can be achieved (Koo et al, 2020…”