Wide Bandgap Organo‐lead Trihalide Perovskites for Solar Cells

Methylammonium lead trihalide perovskite (MAPbX3, where MA is methylammonium, and X is a halide)-based solar cells have been extensively investigated recently, with a demonstrated and certified solar power conversion efficiency (PCE) exceeding 20%. To further boost the PCE beyond the Schockley–Queisser limit, tandem structured solar cells have been investigated based on integrating MAPbX3 and the lower bandgap solar cells. Although the best reported efficiency for this type of tandem cells is not close to the theoretically achievable value, mixed-halide perovskite MAPbBrxI3–x is still one of the most promising candidates as the wide-bandgap light absorber for the tandem application to match the bandgap of silicon, considering its continuously tunable bandgap from 1.6 eV to 2.3 eV with different bromide incorporation ratio. However, the application of the wide-bandgap lead mixed halide perovskite based solar cells has been reported to face several challenges including high intensity of defects, light instability, phase separation, etc. This thesis aims to provide the recent work during my master program involved in the understanding of (1) the characterization of the optoelectronic property of wide-bandgap organolead mixed halide perovskite (MAPbX3), (2) bandgap tunable control of the thin film fabrication process and film post-treatment, (3) device interface and charge transport layers that dramatically influence the efficiency in the MAPbX3 devices, (4) the stability of the MAPbX3 thin films. Advisor: Jinsong Huan