Efficiency enhancement of perovskite-sensitized solar cell based on electrospun titania nanofibers coated in organic-inorganic hybrid metal trihalide nanocrystals

In this work, we have developed highly efficient, flexible, and thermally stable photoanode materials for perovskite-sensitized solar cells (PSCs). Methylammonium lead iodide (MAPbI3 or CH3NH3PbI3) coated TiO2 nanofibers (TNFs) were prepared by two step process. The cubic crystalline nature of MAPbI3 and the semi-crystalline nature of TNFs were confirmed by X-ray diffraction. The functional groups present in the photoanode materials were identified by Fourier-transform infrared spectroscopy. From UV–visible spectral studies, the absorption maximum of MAPbI3-coated TNFs was observed at 754 nm. High-resolution transmission electron microscopy and scanning electron microscopy images of MAPbI3 and TNFs showed a polycrystalline nature and uniform fiber structures, respectively. The highest electrical conductivity of 5.29 × 10−4 S/cm was achieved by the MAPbI3-coated TNFs photoanode, as measured by electrochemical impedance spectroscopy at room temperature. MAPbI3-coated TNFs, Spiro-OMeTAD, and gold chloride were used as the photoanode, hole transport material, and back electrode, respectively, in a PSC. A PSC constructed with MAPbI3-coated TNFs yielded an efficiency of 13.12%, bettering the 11.48% efficiency of a PSCs constructed from MAPbI3-coated TiO2 nanoparticles.