Indium Leaching from Semi-transparent Perovskite Solar Cells: A Voltammetric Approach

In response to the global energy crisis and environmental concerns, the demand for renewable energy sources has increased, with photovoltaics (PV) playing a key role due to its cost efficiency. As an alternative to opaque silicon-based PV cells, semi-transparent perovskite solar cells (PSCs) [1] enable integration in buildings and flexible optoelectronics. However, PSCs suffer from poor stability, especially under humid conditions, leading to the release of hazardous substances such as PbI₂, HI and methylamine. The electrodes of semi-transparent PSCs are typically fluorine-doped tin oxide (FTO) or indium tin oxide (ITO), the latter containing indium, which is toxic and potentially carcinogenic [2]. This work leverages voltammetry to firstly analyse Pb2+ release from ITO- and FTO- based PSCs, and to evaluate indium leaching and mitigation using organic and inorganic additives, in particular perfluoroalkylated pyrenes. While ICP-AES and ICP-MS are widely used for trace metal detection requiring complex instrumentation, voltammetry offers a faster and cheaper alternative [3]. Herein, using the standard addition method, indium was quantified with LOD and LOQ of 0.64 and 2.1 μg/L, respectively (values comparable to ICP-MS), confirming its suitability for trace indium monitoring in environmental matrices. [1] A. Extance, The reality behind solar power's next star material, Nature, 570 (2019) 429-433. [2] T.T. Werner, L. Ciacci, G.M. Mudd, B.K. Reck, S.A. Northey, Looking Down Under for a Circular Economy of Indium, Environmental Science & Technology, 52 (2018) 2055-2062. [3] D. Amorello, S. Barreca, F. Gioè, S. Orecchio, S. Orecchio, Voltammetric methods to quantify hazardous elements (Ni, Pb and Cd) in chocolate and cacao products, Journal of Food Composition and Analysis, 144 (2025) 107682.