Phenoxazine dyes in solid-state dye-sensitized solar cells

► Solid state dye-sensitized solar cell using a series of organic dyes with up to 4.1% efficiency. ► Relation between dye structure and solar cell performance. ► Band-edge shifts due to dipole effects. ► Electron lifetime increase due toalkoxy groups. Several structural modifications have been made to a sensitizer dye based on the phenoxazine core, which was tested in a solid-state dye-sensitized solar cell configuration based on the hole transporting material 2,2′,7,7′,-tetrakis(N,N-di-p-methoxyphenyl-amine)-9,9′,-spirofluorene. Light-to-power conversion efficiencies between 2.5% and 4.1% are reported herein. The difference in device performance is significantly related to the variations of dye molecular structure, with dye molecules having surface protecting alkoxy-groups yielding better solar cell devices. The phenoxazine dyes were characterized by their light harvesting capabilities and electronic properties such as electron recombination lifetime and chemical dipole moment.