Performance and Stability Enhancement of Perovskite Solar Cells Based on Iron-Doped Bi-Electron Transport Layers

This work proposes the doping of bi-electron transport layers consisting of TiO2/SnO2 with iron to facilitate electron movement and recombination reduction, which results in increases in power conversion efficiency and stability enhancement. Two different PSC structures are used: device 1—FTO/TiO2/SnO2/MAPbI3/Spiro-OMETAD/Ag; device 2, a modified device—FTO/TiO2/SnO2 + Fe/MAPbI3/Spiro-OMETAD/Ag. Characterization analysis revealed an improvement in perovskite crystallinity in the modified device; this leads to reductions in trap state density and the recombination of charges that enhance charge extraction. UV-vis absorbance enhancement in the modified device revealed an enhancement in the perovskite layer morphology and good coverage. As a result, PSCs with a short circuit current of 23.35 mA/cm2, open circuit voltage of 1.07 V, fill factor of 0.73, and high PCE of 18.17% are obtained from device 2, compared to PSCs with only 22.13 mA/cm2, 1.03 V, 0.7, and 16.053% for device 1 without Fe doping, respectively. The results reveal that the device based on Fe doping is more stable than the pristine one under stability tests with regard to aging, thermal, stress and prolonged light.