Thin-film-based photovoltaic (PV) technologies have emerged as a promising alternative to conventional silicon solar cells due to their lower material consumption, cost-effectiveness, flexibility, and potential for large-scale integration in diverse applications. This chapter provides a comprehensive overview of various thin-film PV materials, including cadmium telluride (CdTe), copper indium gallium selenide (CIGS), perovskite, and amorphous silicon (a-Si), with emphasis on their structural, optical, and electronic properties. The discussion highlights key synthesis and fabrication techniques, such as sputtering, vapor deposition, and solution processing, along with their advantages and challenges in achieving high efficiency and stability. Recent advancements in device architecture, passivation strategies, and interface engineering are analyzed, showing how these innovations address issues of carrier recombination, moisture sensitivity, and long-term durability. Special focus is placed on perovskite solar cells (PSCs), which have demonstrated rapid efficiency improvements, and on tandem architectures that combine thin films with crystalline silicon (c-Si) to surpass efficiency limits. Furthermore, the chapter explores scalability, environmental considerations, and potential commercialization pathways. Overall, thin-film PV technologies hold significant promise for next-generation solar energy conversion, but continued research is required to improve stability, eco-compatibility, and cost-efficiency for widespread deployment.