Enhancing light harvesting in bilayered dye-sensitized solar cells by tailoring light scattering with electrospun TiO2 nanofibers

Abstract

Dye-sensitised solar cells (DSCs) possess promising features such as high performance under low-light conditions, cost-effectiveness, and adaptability in contrast to conventional silicon-based solar cells. Introducing a scattering layer has been reported to be one of the most effective and economical solutions for improving the efficiency of DSCs. In this regard, various one-dimensional nanostructures have been applied to DSCs to enhance its light scattering property and improve electron transport, thereby achieving a better lifetime. This study highlights the potential advantages of using the well-known electrospinning technique to synthesize various phases of TiO₂ fibers that are effective scattering layers for achieving enhanced light harvesting through improved light scattering and dye anchoring. It was observed that the scattering layer consisting of anatase phase TiO₂ fibers enhanced the power conversion efficiency of nanoparticle-based devices by 60% (8.67% ± 0.58%) primarily owing to the combined effects of improved light harvesting through light scattering and enhanced dye anchoring. However, the rutile phase TiO₂ fibers, as a scattering layer, increased the power conversion efficiency only by 45% (7.85% ± 0.47%). Additionally, perturbation techniques used to investigate the impact of the TiO₂ fiber scattering layer on electron transfer dynamics revealed that the TiO₂ fiber layer contributed to a long electron lifetime and facilitated rapid electron diffusion, thereby promoting efficient charge collection.