Band gap tuning of nickelates for photovoltaic applications

Hybrid perovskites have achieved tremendous success as a light absorber in solar cells during the past few years. However, the stability issue casts shadow on their practical applications. Perovskite oxides may offer an alternative. In this study, the metal–insulator transition in perovskite neodymium nickelates (NdNiO₃) is systematically tuned by adjusting the oxygen partial pressure during film growth. Room temperature insulating films with different band gaps are obtained. Testing photovoltaic cells have been prepared by combining the nickelates with Nb-doped SrTiO₃, and photovoltaic performance has been optimized. Our study offers a new route for designing novel photovoltaic materials. (letter)