Photovoltaic and Impedance Properties of Hierarchical TiO2Nanowire Based Quantum Dot Sensitized Solar Cell
Growth and characterization of TiO2nanowire (NW) assemblies on FTO glass using a typical hydrothermal synthesis have been reported. CdS quantum dots (QDs) have been deposited on TiO2nanowires by successive ion layer adsorption and reaction (SILAR) method. FESEM image exhibits the flower-like hierarchical TiO2bunch of nanowires. HRTEM image confirms the size of CdS QDs between 5 and 6 nm. XRD and absorption studies revealed proper growth of CdS quantum dots on TiO2nanowires. At AM 1.5 illumination intensity, the solar cell, with the configuration FTO/TiO2-NW/CdS-QDs/Pt-FTO, displays a short circuit current (Jsc) of 1.295 mA and an open circuit voltage (Voc) of 0.38 V. TheVocandJscshowed linear behavior at higher illumination intensities. The peak in power-voltage characteristics at various illuminations showed a shift towards higherVocvalues. Capacitance-voltage (C-V), conductance-voltage (G-V), and series resistance-voltage (Rs-V) measurements of the cell in the frequency ranging from 5 kHz to 5 MHz showed decreasing trend of capacitance with increase of frequency whereas increase in conductance and decrease in resistance have been noticed with increase of frequency. All the results including the individual behavior of the plots of capacitance, conductance, and series resistance as a function of bias voltage have been discussed.