Performance Evaluation of Dye-Sensitized Solar Cells Employing Bi-Doped TiO₂ Nanoparticles as Photoanode

Third generation photovoltaic dye-sensitized solar cells (DSSCs) are an area of interest due to their cost-effectiveness and better performance under diffuse light conditions. The design and development of effective photoanodes and their materials still play a significant role and can be explored. Metal doping in TiO₂ semiconductor has been proven to be an effective way for charge separation. The synthesis of bismuth (Bi) doped TiO₂ materials is attempted with different Bi doping quantities through wet impregnation for their utilization in DSSCs. The purpose of the Bi-doped TiO₂ synthesis was to develop an efficient photoanode material with an enhanced charge separation capacity to be applied in DSSC, leading to high current density and overall device performance. The morphology and optical behaviour of synthesized materials were characterized by powder X-ray diffractometer (P-XRD), UV-visible spectrophotometry, field emission scanning electron microscopy (FESEM), Fourier-transform infrared spectroscopy (FTIR), photoluminescence (PL), and thermogravimetric analysis (TGA). The synthesized materials were used to prepare absorption layers of photoanode in DSSCs in conjunction with a ruthenium-based dye (N719). The findings showed that the highest power conversion efficiency (PCE) of the Bi-doped TiO₂-based DSSCs was measured 5.50% using 3% Bi doping to TiO₂ (w/w), surpassing the 3.58% efficiency achieved by the TiO₂-based DSSCs in similar conditions, with an enhancement of ~ 54% in PCE performance. The enhanced performance could be attributed to the incorporation of Bi to TiO₂ which can help with electron transfer in the forward direction in DSSCs circuit by reducing electron–hole recombination.