Guidelines for the design of efficient and injection-resilient thin film photovoltaic converters for indoor applications

Abstract The increasing demand for autonomous, low-power devices in the Internet of Things has highlighted the need for efficient indoor photovoltaic (IPV) solutions. While conventional photovoltaics (PVs) are optimized for outdoor conditions, indoor environments present distinct challenges due to spectral variability and lower irradiance. This work establishes quantitative guidelines for designing efficient and injection-resilient inorganic thin-film PV converters for indoor applications. We analyze three key factors that significantly influence IPV performance: (i) bandgap-to-spectrum matching, demonstrating that a bandgap range of 1.6–1.9 eV is optimal for indoor lighting conditions with minimal sensitivity to correlated color temperature variations, (ii) parasitic absorption losses, emphasizing the impact of charge transport layers, particularly CdS, on reducing efficiency under indoor spectra; and (iii) shunt current losses, revealing that shunt pathways become dominant loss mechanisms at low injection levels, necessitating increased shunt resistance for optimized performance. Additionally, we advocate for standardized reporting of key performance metrics, including incident spectra, external quantum efficiency and shunt-related losses, to facilitate reproducibility and meaningful cross-study comparisons. Our work provides a framework for the practical development of IPV devices through the transparent sharing of the tools developed in this study.