Wilman Septina, Gunawan, Shobih, Natalita Maulani Nursam, Xorell Ivanov Monov, Brian Yuliarto, Nandang Mufti, Henry Setiyanto, Risa Suryana, Huda Alkhaldi, Jade Paranhos Lopes, Nicolas Gaillard
This work reports a fully ink-based, low-temperature strategy (≤250 °C) for fabricating In₂S₃-modified CuInS₂ (CIS) photoelectrodes with enhanced interfacial properties for photoelectrochemical (PEC) water splitting. The In₂S₃ overlayer, deposited via spin-coating from a thiourea-based molecular ink, was optimized to improve charge separation and band alignment at the CIS surface. A two-cycle deposition yielded the best PEC performance, increasing the photocurrent density from 0.25 to 1.75 mA cm⁻² at 0 VRHE and shifting the onset potential anodically from 0.5 VRHE to 0.7 VRHE. Further enhancement was achieved by incorporating a sputtered indium tin oxide (ITO) layer atop In₂S₃, which improved lateral electron conductivity and enabled more uniform Pt catalyst nucleation. This resulted in a photocurrent of 3.5 mA cm⁻², comparable to values obtained with electron scavengers. The improvements are attributed to reduced interfacial charge transfer resistance and more homogeneous catalyst distribution, as confirmed by electrochemical impedance spectroscopy (EIS) and SEM-EDX mapping. These findings highlight the critical role of surface/interface engineering and conductive top layer in developing scalable, high-performance PEC electrodes via low-temperature processing. © 2025 Elsevier B.V.
Research Center for Electronics, National Research and Innovation Agency (BRIN), Jl. Cisitu, Bandung, 40135, Indonesia; Research Collaboration Center for Electrochemistry BRIN-UNDIP, Indonesia; Department of Chemistry, Faculty of Science and Mathematics, Diponegoro University, Semarang, 50271, Indonesia; Advanced Functional Materials Research Group, Faculty of Industrial Technology, Institut Teknologi Bandung, Bandung, 40132, Indonesia; Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Negeri Malang, Jl. Semarang 5, Malang, 65145, Indonesia; Analytical Chemistry Research Group, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung, Bandung, 40132, Indonesia; Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Sebelas Maret, Surakarta, 57126, Indonesia; Physics Department, College of Science and Humanities-Jubail, Imam Abdulrahman Bin Faisal University, P. O. Box 12020, Jubail, Saudi Arabia; Hawaii Natural Energy Institute, University of Hawaii, 1680 East-West Rd Post 109, Honolulu, 96822, HI, United States
