Investigating the Morphology, Optical, and Thermal Properties of Multiphase-TiO₂/MAPbI₃ Heterogeneous Thin-Films for Solar Cell Applications

The present study evaluates the effect of mesoporous multiphase titanium dioxide (TiO₂) nanoparticles (NPs) as an electron transporting layer and investigates the influence of phase com-position on the perovskite solar cell (PSC) performances. This study also aims to evaluate PSC performance using conductive silver ink as an alternative counter electrode. The heterogeneous PSC thin-film solar cells were successfully fabricated and assembled by using a simple a doctor blade and two-step spin coating methods under ambient conditions. Scanning electron microscopy (SEM) mi-crograph images investigate methyl ammonium lead iodide (MAPbI₃) crystal formation on the meso-porous TiO₂ surface structure. Energy-dispersive x-ray spectroscopy (EDX) spectra reveal excellent qualitative and quantitative analysis corresponding to the SEM images in the TiO₂/MAPbI₃ heterogeneous thin films. Thermogravimetric analysis (TGA) characterization reveals that the TiO₂/MAPbI₃ thin films are thermally stable recording a maximum of 15.7% mass loss at 800 °C elevated tem-peratures. Photoluminescence spectroscopy (PL) characterized the effect of multiphase TiO₂ phase transformation on the TiO₂/MAPbI₃ recombination efficiencies. A maximum of 6% power conversion efficiency (PCE) with the open-circuit voltage (Voc) of 0.58 ± 0.02 V and short circuit current (Jsc) of 3.89 ± 0.17 mAcm⁻² was achieved for devices with an active area of 3 × 10⁻⁴ m² demonstrating that the synthesized multiphase TiO₂ nanoparticles are promising for large surface area manufacturing. Therefore, it is apparent that multiphase TiO₂ NPs play a significant role in the performance of the final device.