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

Abstract In this work, low‐cost and simple structure perovskite solar cells (PSCs) were fabricated using formamidinium lead iodide (FAPbI 3 ) as the light absorber and reduced graphene oxide nanofibers (rGO NFs) as the counter electrode (CE). The FAPbI 3 light absorber was prepared using a two‐step solution process, whereas the rGO NFs were synthesized through a simple electrospinning method. The as‐prepared FAPbI 3 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 FAPbI 3 and rGO NFs showed crystalline and bead‐free fiber structures, as confirmed by HRTEM and FESEM image analysis. The AFM topographical images of FAPbI 3 and rGO NFs further reveal the crystalline and fiber structures. XRD pattern analysis confirmed the cubic crystalline phase of FAPbI 3 and the graphitic nature of rGO NFs. From the electrochemical impedance spectroscopy studies, the PSC assembled with the FAPbI 3 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 FAPbI 3 light absorbers and rGO NFs, addressing key challenges in cost and sustainability in solar technology.