Co-sensitization of porphyrin and metal-free dye for panchromatic dye-sensitized solar cells

Abstract

Porphyrin dyes are outstanding photosensitizers. However, one of the limitations of using porphyrin dyes for dye-sensitized solar cells (DSSC) is their weak absorption in the 500–600 nm region. Co-sensitization approach with two complementary dyes is an approach to solve this problem. So, to enhance the DSSC performance by improving harvesting solar light, we have studied porphyrin dye (LD12) and an organic dye (D149) as the co-sensitizer. This co-sensitized LD12 + D149 device with complementary in their spectral responses shows the power conversion efficiency about 6.8%, which is higher compared with the individual LD12 and D149 solar cells. The obtained photon-to-current conversion efficiency (IPCE) by using this co-sensitized solar cell demonstrates a strong and broad spectral response. This improvement is due to increment of the dyes loading amounts, the fine-matched molecular structures and absorptions of both dyes as the co-sensitization system. The co-sensitized LD12 + D149-based DSSC with complementary in their spectral responses, increment of the dyes loading amounts and fine-matched molecular structures exhibited a significant enhancement in the short circuit current (Jsc) and finally the power conversion efficiency (6.8%) relative to the individual single-dye-based DSSC.