Learn about the challenges of producing photovoltaic materials in this NOVA Next article. In 2013, researchers from the University of Oxford created a perovskite solar cell able to convert 15.4% of sunlight to usable energy, an unprecedented efficiency rate. However, perovskite solar cells may not reach the market for quite some time; the development of CIGS cells is a cautionary tale. The photovoltaic capability of copper indium selenide (CIS) was discovered in 1974, and its production was boosted by interest in the development of thin-films solar cells and the addition of gallium (creating CIGS). However, it took over 30 years for CIGS cells to reach the market. This resource is part of the NOVA Next Collection.