Evolution and future prospects of inorganic photovoltaics

Inorganic semiconductors are the backbone of present day photovoltaic (PV) technologies. The highest performance solar cells use Ill-V based materials in complex multijunction device structures and are used primarily in the space industry. The crystalline Si technologies are the mainstay of the commercial terrestrial markets and range from single crystal through large grain polycrystalline materials. Thin film PV technologies, which are approaching large scale manufacturing production levels, consist of polycrystalline CdTe, CuInSe2 and related alloys, and amorphous silicon (a-Si) and related alloys. The paper provides an historical background on the development of these inorganic PV technologies, followed by a discussion of the present status of each technology. The future directions being pursued to improve performance will also be discussed with emphasis on synergies between the technologies.