Photovoltaic and impedance spectroscopic analysis of CdSe quantum dot solar cell

Impedance spectroscopy is a very strong tool for the characterization of photovoltaic devices. We have fabricated a CdSe quantum dot sensitized solar cell based on three layers of nanostructure Tio₂ on FTO and blended with iodine based electrolytes. Photovoltaic properties and impedance spectroscopic analysis of the solar cell are performed using sc-4200 characterization system. We have achieved a short circuit current density of 0.26 ma/cm2 and an open circuit voltage of 0.57 V under AM1.5. The capacitance-voltage, the conductance-voltage, and the series resistances- voltage characteristics of the quantum dot solar cell are measured in the frequency range of 5 khz to 3 mhz. At 5 kHz maximum capacitance is 28 microfarad with bias voltage of 1 v. It decreases sharply at 500 kHz and goes to negative value after 700 kHz. This behavior is due to injection of electrons from the fto electrode into nanostructured layers of Tio₂. The present investigations are useful for the development of quantum dot sensitized solar cell.