Influence of blocking layer on Hf and V doped perovskite structured SrSnO3 for highly efficient dye-sensitized solar cells

SrSnO₃ doped with hafnium and vanadium (SrSnO₃: Hf, V) nanostructures have been effectively created using the precipitation method followed by heat treatment. A thorough examination of the structural, morphological, and physical characteristics of the prepared materials has been conducted. Subsequently, these samples have been employed as a blocking layer in dye-sensitive solar cells to assess their photovoltaic properties. The XRD pattern and refinement parameters confirm that an orthorhombic perovskite crystal structure with structural purity has been formed. FTIR spectra identify the presence of metal oxide (Sn-O) vibrations at 644 and 647 cm⁻¹. The active Raman modes due to Sn-O movements are observed at 225 & 223 cm⁻¹ for Hf and V doped samples. The electron micrographs disclose the nanorods for all the samples. The deconvoluted XPS spectra reveal the oxidation state and oxygen vacancies. The incorporation of dopants into SrSnO₃ results in a change in surface area from 11.8 to 9.2 m²/g. UV–visible spectra are used to investigate the steep optical absorption behaviour of the prepared materials. Bandgap alteration evidences the interaction of Hf and V with the Sr-Sn-O lattice. The multi-colour emission in the photoluminescence spectra confirms the presence of defects in the samples, a fact also confirmed by the XPS spectra. The blocking layer made with Hf and V-doped samples prevents back electron transfer, resulting in a significant improvement in photovoltaic performance. Vanadium (V1)-doped SrSnO₃, with Jsc (9.36 mA/cm²), Voc (0.828 V), and fill factor (74 %), exhibits the highest efficiency. These results provide a pathway for blocking layer research, particularly in oxide-based perovskite materials.