BaBiO3: A potential absorber for all-oxide photovoltaics

BaBiO3 is presented as a potential absorber for all-oxide solar cells. Thin-films of BaBiO3 were deposited by pulsed laser deposition. As-deposited thin-films were amorphous, but a rapid thermal anneal at 600 degrees C for 10 min yields polycrystalline thin-films. X-ray photoelectron spectroscopy measurements show that deposited films have Barium in Ba-12 state and bismuth in both Bi-13 and Bi-15 state. UV-Vis spectrophotometer (UV-Vis) shows that BaBiO3 films have direct and indirect bandgap (E-g) of 2.25 eV and 2.02 eV respectively, while ultraviolet photoelectron spectroscopy (UPS) shows that valence band maxima (E-V), conduction band minima (E-C) and work-function (phi) of BaBiO3 is at 5.82 eV, 3.8 eV and 4.22 eV respectively. BaBiO3 thin-film devices with a FTO/c-TiO2/BaBiO3/Au structure show rectifying current-voltage characteristics in dark. Under illumination, a photo response with a J(light)/J(dark) ratio of 1.75 is observed. (C) 2017 Elsevier B.V. All rights reserved.