Editorial: Advances in Emerging Thin Film Photovoltaics for Solar Energy Conversion

Feng Yan^1,2*Kaiwen Sun^3*Subhadra Gupta^4*

• ¹Arizona State University, Tempe, United States
• ²Arizona State University School for Engineering of Matter Transport and Energy, Tempe, United States
• ³University of New South Wales School of Photovoltaic and Renewable Energy Engineering, Sydney, Australia
• ⁴Department of Metallurgical and Materials Engineering, The University of Alabama, Tuscaloosa, United States

The objective of this collection is to highlight innovative strategies that enhance the efficiency, reproducibility, and manufacturability of thin-film photovoltaic devices. Achieving commercial viability requires precise control over material deposition, optimized interfacial alignment, robust modeling for performance diagnostics, and a deep understanding of defect-related phenomena. The contributions in this issue tackle these challenges through a blend of experimental and theoretical approaches, providing a comprehensive perspective on the future of thin-film photovoltaics.Belmahdi et al. focus on parameter extraction for photovoltaic modules, presenting a comparative analysis of six analytical and numerical methods based on the single diode model (SDM) (10.3389/fenrg.2025.1501335). These methods, developed by Khan et al., Blas et al., Phang et al., Vika, Cubas et al., and Almonacid et al., are evaluated under standard test conditions, with a focus on maximum power point current and voltage. The study demonstrates that the Phang et al. approach excels in predicting photocurrent-voltage (I-V) and power-voltage (U-V) curves, achieving lower errors (e.g., root mean square error, mean bias error, normalized RMSE, mean absolute percentage error, and absolute error) compared to other methods, particularly Almonacid et al., which underestimates the I-V curve at maximum power. This work establishes a robust framework for performance diagnostics, applicable to both conventional and perovskite-based modules, enhancing the accuracy of module characterization.Brown and Li provide a comprehensive review of carbon-based perovskite solar cells (PSCs), which offer cost-effectiveness, simplified production, and enhanced stability compared to devices with metallic electrodes (10.3389/fenrg.2024.1463024). Their analysis highlights the critical challenge of poor contact quality at the carbon/perovskite interface, which limits device performance. By examining strategies such as chemical passivation and interface modification, the review outlines a roadmap for improving efficiency and scalability. These advancements position carbon-based PSCs as a promising direction for commercial development, addressing key barriers to widespread adoption of perovskite technologies.Menon and Yan explore four-terminal (4T) perovskite-cadmium telluride (CdTe) tandem solar cells, combining SCAPS simulation with experimental validation (10.3389/fenrg.2024.1457556). Their simulations demonstrate a power conversion efficiency (PCE) exceeding 23%, confirming the architecture's feasibility. Experimentally, they achieve tandem efficiencies of 18.2% and 19.4% by pairing wide-bandgap perovskite cells (1.6 eV and 1.77 eV) with a narrow-bandgap CdTe cell (1.5 eV). The 1.77 eV perovskite proves more suitable for optimal spectral utilization, highlighting the potential of 4T tandems to surpass single-junction efficiency limits while leveraging mature CdTe technology. This work underscores the importance of device architecture engineering for next-generation photovoltaics.Munoz-Diaz et al. investigate hysteresis in MAPbI3-based devices, comparing a 15% efficient PSC to a memristor lacking directional photocurrent (10.3389/fenrg.2022.914115). Using currentvoltage curves and impedance spectroscopy, they identify a significant inverted hysteresis effect at forward bias, attributed to a chemical inductor component in the equivalent circuit. Their findings classify electrical responses based on recombination in selective-contact devices and voltage-activated conduction in symmetric-contact devices. By establishing a link between PSC and memristor behavior, this study highlights the multifunctional potential of perovskites in energy and memory applications, while raising critical questions about long-term stability due to ion migration and trap states.Moser et al. advance the understanding of (Cs0.07FA0.93)PbI3 perovskite film formation through a two-step vapor deposition process. An inorganic CsI/PbI2 precursor stack is deposited via thermal evaporation, followed by chemical vapor deposition (CVD) with formamidinium iodide (FAI) (10.3389/fenrg.2022.883882). Their study reveals that substrate surface properties and thermal treatment during the initial CVD phase significantly influence precursor crystallinity and morphology. Cesium diffusion through PbI2 ensures uniform elemental composition, enhancing film quality. These insights provide a foundation for scalable, high-quality perovskite films, critical for industrial applications of thin-film photovoltaics.Fru et al. explore compositional tuning in MAPb(I1-xBrx)3 thin films prepared by sequential physical vapor deposition of MAPbBr3 on MAPbI3 (10.3389/fenrg.2021.667323). By varying MABr thickness (300-500 nm), they achieve bandgaps from 2.21 to 2.14 eV, with bromine content (x = 0.89-0.95) decreasing as thickness increases. X-ray diffraction confirms a structural transition from tetragonal MAPbI3 to cubic-like MAPbBr3, accompanied by improved grain size (150-320 nm) and charge carrier mobility. Device PCEs range from 0.56% (MAPbBr3) to 1.15% (MAPbI3), with Mott-Schottky analysis revealing a built-in voltage of 1.6 V in bromine-rich films compared to 0.7 V in MAPbI3 devices. This work underscores the role of compositional control in optimizing optoelectronic properties for tailored solar harvesting applications.The current state and future directions of thin-film photovoltaics are listed below: We express our deepest gratitude to the authors for their outstanding contributions. We also thank the reviewers for their rigorous and insightful evaluations, which significantly enhanced the quality of this collection. The collaborative efforts of the editorial and production teams were instrumental in bringing this Research Topic to fruition. We hope these insights will inspire and guide future advancements, as the global research community continues to drive innovation in thin-film photovoltaics for sustainable solar energy conversion.1. Intal, D. and Ebong, A., 2024.