Revolutionizing perovskite solar cells: Enhancing current density through Zr doping in MAPbBr3 to engineer shifted band gap edges near the electron transport layer

In this study, perovskite films of CH3NH3PbBr3 (referred to as MAPbBr3) doped with varying concentrations of Zr (0%, 2%, and 4%) were synthesized using a sol-gel spin coating technique. X-ray diffraction (XRD) analysis confirmed the retention of the cubic structure in MAPbBr3, indicating high crystallinity. Notably, the 2% Zrdoped film exhibited a significantly larger grain size (74 nm). Importantly, the bandgap energy of the 2% Zrdoped MAPbBr3 film decreased, accompanied by a higher refractive index. Moreover, the conduction band edge of this film closely approached the conduction band edge of the electron transport layer, rendering it promising for solar cell applications. Solar cells were fabricated using the configuration FTO/TiO2/MAPbBr3/ spiro-OMeTAD/Au. Remarkably, the solar cell based on the 2% Zr-doped MAPbBr3 film demonstrated exceptional performance characteristics: a notably high current density of 9.05 mA/cm2, an open-circuit voltage of 1.034 V, a favorable fill factor of 0.7636, and a remarkable efficiency of 7.15%. Furthermore, impedance analysis indicated that the 2% Zr-doped MAPbBr3 film exhibited a reduced recombination rate. In conclusion, our study underscores the efficacy of Zr doping in MAPbBr3 perovskite films, particularly the 2% Zr-doped variant, in enhancing the photovoltaic performance of solar cells. This work opens avenues for further advancements in perovskite solar cell technologies through controlled doping strategies.