Utilizing the sol–gel technique, we deposited 5% Mo-doped MAPbI2Br films onto fluorine-doped tin oxide (FTO)-glass substrates. X-ray diffraction (XRD) analysis confirmed the cubic structure of all films, with the 5% Mo-doped film exhibiting a notably large grain size of 32.34nm. UV–visible spectroscopy further validated these findings, indicating a reduced band-gap energy of 1.94eV and a heightened refractive index of 2.64 and an extinction coefficient of 2.21 in the 5% Mo-doped film. The manipulation of the conduction and valence band edges facilitated enhanced charge transport between the layers. In order to increase the current density, a layer of SnO2 has been added near the electron transport layer (ETL). XRD and Raman spectra show the formation of crystalline SnO2. The absorption spectra show the high transmittance in the visible region, which is good for ETL. Solar cells based on these films were constructed with the configuration glass FTO/TiO2/SnO2/Mo-MAPbI2Br/spiro-OMeTAD/Au. The bilayer composed of 5% Mo-MAPbI2Br and a SnO2 layer demonstrated excellent performance, characterized by a current density of 11.88mA/cm2, an open circuit voltage of 1.07V, a fill-factor of 0.83, and an efficiency of 10.03%. The improvement in performance may be credited to the increased speed of electron transport and decreased likelihood of recombination at the interface between TiO2, SnO2, and perovskite layers in the bilayer structure.
