Engineered electronic properties of the spin-coated MAPI for hole-transport-free perovskite solar cell (HT-free PSC): Spinning time and PSC performance relationship

We report a simple method to prepare an efficient hole-transport-free perovskite solar cell (HT-free PSC) directly on fluorine-doped tin oxide (FTO) by spin coating of precursors with various spinning times. X-ray diffraction (XRD) results exhibited an improvement in the crystallinity of fabricated PSC with increase spinning time. The optical studies clearly revealed a similarity in the transmittance spectra and the band gap (1.52 eV) of prepared PSCs. The field emission scanning electron microscope (FESEM) and atomic force microscope (AFM) images showed increasing in the perovskite grain size with increase spinning time. All photovoltaic parameters such as short circuit current (J(sc)), open circuit voltage (V-oc), and fill factor (FF) demonstrated enhancement at long spinning time due to increase light absorption and photo-generated current. The highest PCE was achieved by PSC fabricated at spinning time of the 60 s.