Efficient Panchromatic Light Harvesting with Co-Sensitization of Zinc Phthalocyanine and Bithiophene-Based Organic Dye for Dye-Sensitized Solar Cells

Co-sensitization by using two or more dyes with complementary absorption spectra as sensitizers of a semiconductor to expand the spectral response range of dye-sensitized solar cells (DSSCs) is an effective approach to enhance device performance. To improve the light-harvesting capability in the near-infrared (IR) region, zinc phthalocyanine (Zn-tri-PcNc-1) was applied to combine with a D-pi-A triarylamine bithiophene cyanoacrylate-based organic dye (DH-44) for fabrication of a co-sensitized solar cell. The resulting co-sensitized device shows an efficient panchromatic spectral response feature in the range of 320-750 nm and gives an overall conversion efficiency of 6.61%, which is superior to that of the individual dye-sensitized solar cells under standard AM 1.5G one sun irradiation. The above results represent a clear advance toward efficient and low-cost co-sensitized solar cells with a panchromatic spectral response.