Sequential physical vapor deposited methylammonium lead tri-iodide perovskites on FTO and ITO modified zinc oxide nanorods for perovskite solar cells

Abstract

A comparative study was conducted between methylammonium lead tri-iodide (MAPbI3)/zinc oxide (ZnO) nanorods (NRs) on fluorine-doped tin oxide (FTO) and indium tin oxide (ITO) substrates for the first time. X-ray diffraction micrographs confirmed pure tetragonal MAPbI3 phase with I4/mcm space group and highly textured wurtzite hexagonal ZnO structure, having P63mc space group. Scanning electron micrographs revealed compact MAPbI3 grains on vertically aligned NRs. The average diameter of the NRs was 226 nm on ITO and 233 nm on FTO. Similarly, the average grain sizes of MAPbI3 were 280 nm and 210 nm on FTO/ZnO and ITO/ZnO, respectively. The bandgaps were respectively 3.05 and 3.18 eV for ITO/ZnO and FTO/ZnO, whereas that of FTO/ZnO/MAPbI3 and FTO/ZnO/MAPbI3 were 1.580 and 1.584 eV, accordingly. Our findings indicate that FTO/ZnO/MAPbI3/Au solar cells have a better performance than ITO/ZnO/MAPbI3/Au devices, and in-chamber annealing did not decompose MAPbI3 sequential vapor-deposited on ZnO nanorods.