Thin-film solar photovoltaics: Trends and future directions
Donald Intal, Abasifreke U. Ebong
Abstract
Thin-film photovoltaics offer pathways to scalable, low-cost, and unconventional applications of solar energy. The established thin-film technologies include amorphous silicon ( a -Si), cadmium telluride (CdTe), and copper indium gallium selenide (CIGS). While the emerging thin film explore perovskites, copper zinc tin sulfide, quantum dots, organic photovoltaics, and dye-sensitized solar cells. GaAs and related III-V thin films set the efficiency roadmap notwithstanding the niche terrestrial economics. This review article on thin film photovoltaics focuses on benchmarking criteria which include, efficiency, field stability and degradation, temperature coefficients, material pertinence, scalability, technology readiness and localized cost of electricity (LCOE). Cadmium telluride and copper indium gallium selenide are the most commercially mature, pairing laboratory efficiencies of 23.1 % and 23.6 % with multi-gigawatt production. Perovskites have advanced swiftly (26.7 % single-junction) and are progressing toward perovskite/silicon tandems. GaAs and III-V thin films dominate the space applications because of their resilience to radiation. At the system-level cost modeling indicates competitive levelized cost of electricity: (i) cadmium telluride costs from $38 to $65 per megawatt-hour (similar to crystalline silicon at $38 to $78 per megawatt-hour); (ii) copper indium gallium selenide in the high $50s per megawatt-hour given scale and materials constraints; (iii) and perovskite/silicon tandems at $40 to $45 per megawatt-hour based on, at least 25-year stability and reduced weighted average cost of capital. Although thin-film photovoltaics use less material and enable lightweight, flexible formats, broader deployment hinges on robust interfaces and encapsulation, as well as the environmental impact.