Epitaxial growth of BaSnO3 film as inorganic electron transport layer for CsPbI2Br solar cell application

[Display omitted] •BaSnO3 films were epitaxial grown under different growth pressure.•Concentration of oxygen vacancies plays an important role on the electrical properties of BaSnO3 films.•Controlling the oxygen vacancy is an effective way to improve the performance of CsPbI2Br solar cells. The inorganic electron transport layer BaSnO3 films were epitaxially grown on Nb:SrTiO3 substrates by pulsed laser deposition. The effect of growth oxygen pressure on the oxygen vacancies in the BaSnO3 was demonstrated by the X-ray photoelectron spectroscopy. The intrinsic relationship between oxygen vacancy concentration and lattice stress in the BaSnO3 films was analyzed based on the X-ray diffractometer and the X-ray photoelectron spectroscopy. By adjusting the oxygen pressure, the BaSnO3 films with low resistivity and high electron mobility were obtained. The optimal photoelectric conversion efficiency of CsPbI2Br solar cell with BaSnO3 films as electron transport layer reached 11.71%.