Tuning the band gap edges of perovskite material by Cd doping for achieving high current density in perovskite solar cells

Defect-free perovskite materials are necessary for developing efficient solar cells. On FTO-glass substrates (0%, 3%, and 6%), cadmium-doped methylammonium lead bromide (Cd-MAPbBr3) films have been deposited. Doping does not affect the cubic crystal structure of MAPbBr3; however, it has increased the grain size, according to XRD. The band gap is decreased at 3% of Cd doping, due to which the deep-level traps are decreased. Every cell shows good performance, but the cell formed with 3% Cd doping has a high fill factor (0.81), open circuit voltage (1.04 V), considerable short-circuit current density (7.2 mA/cm2), and efficiency (6.05%). The high open circuit voltages and current density refer to the accumulation of charges at the holes and electrons transport layers being reduced due to Cd doping.