Thin Films: Past, Present, Future

Abstract Thin‐film photovoltaics was developed as a means of substantially reducing the cost of photovoltaic (PV) systems. The rationale for this was that thin‐film modules would be cheaper to manufacture owing to their reduced material costs, energy costs, handling costs and capital costs. However, thin films had to he developed using new materials, including amorphous silicon, copper indium diselenide, cadmium telluride and film crystalline silicon. In all cases, these technologies faced major technical and financial hurdles. The most crucial technical barriers are described within the text. Today, much progress has been made and the performance of the best thin‐film laboratory cells approaches the best performance of polycrystalline silicon cells. Outdoor stability has been a problem, especially with amorphous silicon, but this material and newer thin films now display good to excellent stability. It appears that the goal of thin films—truly low‐cost PV electricity that can be sold into energy‐significant markets—can be achieved. However, its achievement will require both the continuing resolution of technical problems and the ongoing investment of significant public and/or private resources.