Polycrystalline thin-film technologies: status and prospects

The progress towards high-efficiency thin-film polycrystalline solar cells is examined in this paper together with a brief history of their development. We focus on the three materials of contemporary interest for such devices: polycrystalline Si, CuInSe₂ and its alloys, and CdTe. Although there has often been an implicit assumption that thin-film devices required a compromise of lower efficiency than their single-crystal, or bulk polycrystalline competitors, we now see, for the first time, that polycrystalline thin-film solar cells can rival these devices. In dispelling this myth, we examine the elements that have contributed to the progress in each area