Thin-film solar cells are a type of photovoltaic technology that converts sunlight into electricity. They are made by depositing one or more thin layers of photovoltaic material onto a substrate, which can be flexible or rigid. This design allows for lightweight and versatile applications, making them suitable for various surfaces, including rooftops and portable devices. These solar cells typically use materials like cadmium telluride, copper indium gallium selenide, or amorphous silicon. While they generally have lower efficiency compared to traditional crystalline silicon solar cells, their lower production costs and flexibility make them an attractive option for certain applications in renewable energy.