Synthesis and characterization of lead-free perovskite thin film deposited using spin coating technique

Abstract

Perovskite solar cell (PSC) technologies are viewed as promising innovation and have sparked a lot of interests due to their efficiency, ease of manufacture, and low energy and environmental impacts. The performance of PSC has improved quickly in recent years, with the current record of 25.6 % power conversion efficiency (PCE). The purpose of this thesis is to fabricate methylammonium tin triiodide, CH3NH3SnI3 perovskite thin film using spin coating technique. By manipulating spin rate and the precursor concentration, the structural and optical properties of microscope perovskite thin film were investigated and characterised using scanning electron -SEM, atomic force microscope-AFM, X-ray diffraction-XRD, and Ultraviolet-Visible spectroscopy respectively. The XRD result showed that CH3NH3SnI3 perovskite material exhibits intense peaks corresponding to the plane (100) and (200) at the angles of 14º and 28º. The results from AFM revealed that perovskite film fabricated at 2000 rpm with 1.0 M of precursor concentration showed a uniform and consistent surface structure with a root mean square roughness (Rrms) of 20.70 nm. From SEM analysis, perovskite thin film fabricated at 2000 rpm with precursor concentration of 1.0 M showed a significant homogeneous and uniform layer. From UV-Vis data, the highest absorption spectra was demonstrated by the perovskite film with 1.0 M concentration and fabricated at 2000 rpm spin rate. By controlling the spin rate and precursor concentration during the fabrication process, it was shown that 2000 rpm and 1.0 M are the best parameters for good perovskite thin film quality for solar cell application.