Efficiency enhancement for cocktail dye sensitized nb2o5photoanode towards 2 5 dye sensitized solar cell

Abstract

In present report, we have developed Nb2O5photoelectrode sensitized with cocktail dye as sensitizer towards enhancement in efficiency. The absorbance spectrum of pristine organic dyes viz. coumarin 343 (C343) and mercurochrome (MC) along with mixture of C343 and MC (cocktail) dye was recorded using UV-visible spectroscopy. The performances of Nb2O5based photoanode were characterized using photocurrent density-voltage (J-V) measurement and the comparison of output photovoltaic performance for C343, MC and cocktail dye were discussed in detailed. Cocktail dye sensitization shows enhancement in short-circuit current density (J oc) due to the complementary absorption of the two sc pristine sensitizers. The value of open circuit voltage (V oc) for device sensitized using cocktail dye comes between the individual V for pristine dye sensitized devices. Electrochemical impedance spectroscopy (EIS) was studied to understand the charge transfer. Based on EIS measurements, the increased efficiency value of the solar cell with the cocktail dye sensitized photoanode can be attributed to suppression of charge recombination at Nb2O5|dye|electrolyte interfaces and enhancement of electron transport in the photoanode along with the longer electron lifetime. The overall conversion efficiency reaches 0.70% for cocktail dye sensitized device.