A thin-film solar cell is a solar cell that is made by depositing one or more ultra-thin layers (much thinner than a human hair), or thin-film of photovoltaic material on a substrate, such as glass, plastic or metal. Thin-film PV was born out of the energy crisis of the 1970s. Determined to reduce the world’s reliance on fossil fuels, glass pioneers Harold McMaster and Norman Nitschke began exploring ways to commercialise and scale solar energy while also finding a new outlet for the glass industry. McMaster understood that scaling PV production was imperative to driving down the cost of solar electricity and meeting growing energy demands.
Harold McMaster was convinced that PV cells could be created by coating large glass substrates with a layer of conductive metal, similar to the way tinted glass is manufactured. He envisioned integrating the panel-coating process into “float lines” in the glass industry so that every glass plant could turn out windows one day and produce solar panels the next. The successful development of the Vapor Transport Deposition process led to the large-scale production of thin-film PV modules which could be manufactured nearly 600 times faster than conventional crystalline silicon modules.
Unlike the crystalline silicon PV batch process, thin-film PV modules are manufactured in a single continuous process by depositing semiconductor material on inexpensive substrates such as glass or plastic. A sheet of glass can be transformed into a finished PV module in less than 3.5 hours compared to crystalline silicon wafers, which can take up to three days. By using compound semiconductors , such as gallium arsenide (GaAs), cadmium telluride (CdTe), copper indium disulphide (CIS) and copper indium gallium di-selenide (CIGS), as well as solution based metal-organic semiconductors, such as methyl-ammonium-lead-iodide (MAPI) – better known as Perovskite – , thin-film modules absorb light up to 100 times more effectively than conventional materials such as silicon.
According to a recent IEA report (February 2020), renewables, including solar, wind, hydro, biofuels and others, play a leading role in the energy transition and their power capacity is expected to expand by 50% between 2019 and 2024. In particular, the report highlights that solar PV will play a central role, as it alone accounts for almost 60% of the expected growth.