Structure and optical properties of Sb-doped CH3NH3PbI3: effect on perovskite solar cell performance

In this paper, we have shown that Sb has been doped into the light-absorbing methylammonium lead iodide (CH3NH3PbI3) perovskite. We had anticipated that the introduction of antimony (Sb3+) as a dopant in perovskite would result in improved light-absorbing properties for use in photovoltaic cells, including longer carrier lifetimes and an ideal band gap. We used a simplified and cost-effective method to fabricate thin films of CH3NH3PbI3 perovskite doped with antimony, which were deposited onto cleaned FTO substrates using a modified two-step spin-coating process. To evaluate the characteristics of these films, we utilized three different techniques: XRD, SEM, and UV-Vis spectroscopy to analyze their structural, optical, and dielectric properties. It was discovered that the optical band gap varied with Sb-doping concentration. The XRD data showed that there were no additional peaks, suggesting that Sb was able to partially replace Pb2+ successfully. However, the crystallinity increased with doping up to 1.0%, but decreased at higher concentrations. This finding aligns with the SEM morphology of the resulting films, which exhibited regular crystallites on a more even, compact, and complete surface. Finally, the IV curve showed improvement in the performance of the fabricated PSCs by increasing the Sb-doping ratio until 2.0% but decreased at the high concentration of 3.0%.