Enhanced Structural, Optical, and photovoltaic properties of Sm-Doped MAPbI2Br perovskite solar cells

Abstract

Samarium-enhanced methylammonium lead iodide bromide (Sm-MAPbI2Br) thin films were applied onto FTO-glass substrates. X-ray diffraction (XRD) analysis revealed an enlargement in grain size to 29.09 nm, a decrease in dislocation line density to 4.32 x 1015 m−2, an expansion in d-spacing to 5.18 Å, a reduction in lattice constant to 1.59 Å, and a diminished volume in the cubic crystal lattice of MAPbI2Br. The incorporation of Sm2+ ions resulted in a narrowed band gap energy (1.95 eV), an augmented refractive index (2.65), and a decreased extinction coefficient (2.24). The solar cell constructed with a 5 % Sm2+ doping level demonstrated an enhanced open-circuit voltage of 1.05 V, a notable increase in short-circuit current density to 9.87 mA/cm2, a fill factor of 0.80, and an elevated efficiency reaching 9.32 %. Comparative analyses suggest that the cell with 5 % Sm2+ doping experiences a lower rate of recombination compared to undoped MAPbI2Br-based cells. EIS is used to investigate enhanced charge transport in hybrid MAPbI2Br devices, emphasizing the impact of a Sm-doped thin layer on carrier dynamics. The robustness of the open-circuit voltage highlights the potential of layering MAPbI2Br in the development of highly efficient solar cells.