Photovoltaic response of dye-sensitized solar cell using 2′,7′-dichlorofluorescein as an organic dye

Dye-sensitized solar cell (DSSC) was fabricated by using 2′,7′-dichlorofluorescein as an organic dye sensitizer (metal free dye). A FTO/titanium dioxide (TiO₂) electrode was dipped in a solution of 2′,7′-dichlorofluorescein and covered with another FTO electrode to form dye-sensitized solar cell. Using dyes in the fabrication of solar cells increases the efficiency of the solar cell. The photovoltaic and impedance spectroscopy properties of the solar cell were investigated. A beam of light of different intensity was focused on the surface of the DSSC to measure the open circuit voltage, the short circuit current, the output power and the fill factor. The capacitance-voltage, the conductance-voltage, the series resistance-voltage characteristics of the solar cell were measured in a wide range of frequency for the first time for DSSC applications. Owing to the injection of electrons from the FTO electrode into TiO₂, the capacitance-voltage characteristic shows the behavior from the (+ve) to (-ve) capacitance. The photovoltaic of the DSSC can be improved using various organic semiconductors. Photons striking the dye with enough energy to be absorbed create an excited state of the dye, from which an electron can be "injected" directly into the conduction band of the TiO₂ From there it moves by diffusion to the clear anode on top.