Formamidinium Lead Iodide-Based Perovskite Solar Cell Fabrication With an Electrospun-Reduced Graphene Oxide Back Electrode: A Novel Approach

In this work, low-cost and simple structure perovskite solar cells (PSCs) were fabricated using formamidinium lead iodide (FAPbI₃) as the light absorber and reduced graphene oxide nanofibers (rGO NFs) as the counter electrode (CE). The FAPbI₃ light absorber was prepared using a two-step solution process, whereas the rGO NFs were synthesized through a simple electrospinning method. The as-prepared FAPbI₃ and rGO NFs were characterized by high-resolution transmission electron microscopy (HRTEM), field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), and X-ray diffraction (XRD) pattern analysis. The surface morphology of the as-prepared FAPbI₃ and rGO NFs showed crystalline and bead-free fiber structures, as confirmed by HRTEM and FESEM image analysis. The AFM topographical images of FAPbI₃ and rGO NFs further reveal the crystalline and fiber structures. XRD pattern analysis confirmed the cubic crystalline phase of FAPbI₃ and the graphitic nature of rGO NFs. From the electrochemical impedance spectroscopy studies, the PSC assembled with the FAPbI₃ light absorber and rGO NFs-based CE demonstrated an electrical conductivity of 3.64 × 10⁻⁴ S cm⁻¹. The fabricated PSC device achieved an efficiency of 8.78% compared to the 7.49% efficiency of the device with a sputtered gold CE. This work uniquely integrates advanced materials, cost-effective manufacturing, and enhanced efficiency in PSCs using FAPbI₃ light absorbers and rGO NFs, addressing key challenges in cost and sustainability in solar technology.