Nanda Nafi'atul Khusna, Markus Diantoro, Herlin Pujiarti, Yuda Prima Hardianto, Edson Leroy Meyer
A scalable and cost-effective post-treatment strategy for enhancing the performance of dye-sensitized solar cells (DSSCs) is presented based on a single-bath solution process that integrates TTIP-induced TiO₂ necking with Al₂O₃ interfacial passivation. In this approach, mesoporous TiO₂ photoanodes were post-treated using a mixed TTIP/Al₂O₃ precursor solution with systematically varied Al₂O₃ content (1–4 wt%), enabling simultaneous improvement of interparticle connectivity and suppression of interfacial charge recombination. Structural and morphological analyses confirm the formation of anatase TiO₂ and the successful incorporation of Al₂O₃, accompanied by controlled particle growth and reduced photoanode porosity. Optical characterization reveals preserved dye sensitization and effective visible-light harvesting. Photovoltaic measurements demonstrate a significant enhancement in device performance, with the optimal TiO₂–3% Al₂O₃ photoanode achieving a power conversion efficiency of 8.65%, compared to 4.01% for the untreated TiO₂ device. Single-diode model fitting of the current–voltage characteristics indicates a substantial reduction in saturation current, evidencing suppressed recombination. Electrochemical impedance spectroscopy further confirms minimized photoanode charge-transfer resistance for the TiO₂–3% Al₂O₃ sample, consistent with prolonged electron lifetime and improved charge collection. These results demonstrate that the proposed one-bath TTIP/Al₂O₃ post-treatment offers an effective and scalable alternative to atomic layer deposition for interfacial engineering in DSSCs, providing a balanced optimization of charge transport and recombination suppression. © 2026
Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Negeri Malang, Jl. Semarang No. 5, Malang, 65145, Indonesia; Center of Advanced Materials for Renewable Energy, Universitas Negeri Malang, Jl. Semarang No. 5, Malang, 65145, Indonesia; Fort Hare Institute of Technology, University of Fort Hare, Eastern Cape, Alice, 5700, South Africa
