A single layer deposition of Li-doped mesoporous TiO2 beads for low-cost and efficient dye-sensitized solar cells

Herein, we report a new strategy for improving the efficiency and reducing the fabrication cost of dye-sensitized solar cells (DSCs) by elimination of the three- or four-fold layer deposition of TiO2. This is performed by replacing a single layer deposition of mesoporous TiO2 beads, with sub-micrometer size, high surface area and tunable pore size, synthesized by a combination of sol-gel and solvothermal methods. Furthermore, superior electronic properties gained by a reduction in electronic trap states are achieved through doping of pristine TiO2 beads with lithium. The beads have a spherical shape with monodispersed texture consisting of anatase-TiO2 nanocrystals and ultra-fine pores. The outstanding light scattering and harvesting characteristics of the beads emerge from a combination of tailored morphology and crystal structures. These have resulted in a 40% increase in solar to electric power conversion efficiency, for a single spin-coated film without an additional scattering layer and pre- and post-treatment with TiCl4 solution, compared to the reference nanoparticulate TiO2 device.

Automated summary

This study introduces a new strategy to improve the efficiency and reduce the fabrication cost of dye-sensitized solar cells by eliminating the multi-layer deposition of TiO2. By replacing it with mesoporous TiO2 beads with specific characteristics and doping them with lithium, the electronic properties are enhanced. The spherical beads with tailored morphology and crystal structures show outstanding light scattering and harvesting characteristics, resulting in a 40% increase in solar to electric power conversion efficiency.