In an attempt to investigate influence of the utilization of organic dyes on photovoltaic performance of low-cost dye-sensitized solar cells (DSSCs), carminic acid (CA) obtained from cochineal insect was employed as photosensitizer to fabricate DSSCs. To recognize light absorption behavior of the CA, UV-Vis spectroscopy was taken. The CA comprises noticeable spectrum of solar radiation, 430 to 540 nm that makes it appropriate for use as a photosensitizer in DSSCs. Fourier transform infrared (FTIR) spectra of the CA revealed the presence of carboxylic functionality, enabling good anchorage to the surface of TiO2. The electrochemical impedance spectroscopy (EIS) analysis manifests that the suppression of the electron recombination at the TiO2/CA/electrolyte interface was insufficient. Quantum chemical calculations of the CA dye were performed by using the density functional theory (DFT). The lowest unoccupied molecular orbital (LUMO) level of the CA matched well for the injection of electron from the CA to the conduction band edge of TiO2. The achieved photo-conversion efficiency of a DSSC employing the CA photosensitizer was 1%, which was found to be much higher than that of several natural dyes-based DSSCs under a simulated solar light illumination of 100 mW/cm2.
DOI: 10.1002/er.6883