Perylene imide dyes for solid-state dye-sensitized solar cells: Spectroscopy, energy levels and photovoltaic performance

We report the solid-state dye-sensitized solar cell performances of perylene imide using nanoporous TiO2 electrodes. Solid-state dye-sensitized solar cells were fabricated using the organic hole-transporting medium (HTM) 2,2′7,7′-tetrakis-(N,N-di-p-methoxyphenyl-amine)-9,9′-spirobifluorene (spiro-OMeTAD). The experimental ELUMO levels of perylene imide dyes are found to be 3.75 and 3.77eV, respectively. Therefore, perylene imide dyes can inject electrons to the conduction band of titanium dioxide in organic dye-sensitized solar cells. TiO2 thin films of about 2μm in thicknesses were prepared. Both preparation and thickness of the compact TiO2 layer were optimized using spray pyrolysis. The studies revealed that an optimum film thickness of 130–150nm of compact TiO2 yielded the best rectifying behavior and SDSC performance. In this work, our goal was to investigate the performance of perylene sensitizers in connection with spiro-OMeTAD hole transport material. Short-circuit current densities, open circuit voltages and overall conversion efficiencies of the solar cell with 2,2′7,7′-tetrakis-(N,N-di-p-methoxyphenyl-amine)-9,9′-spirobifluorene(spiro-OMeTAD) as a hole conductor and perylene imide as sensitizer on mesoporous TiO2 were investigated.