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.