Nanoarchitectured Semiconducting Photoelectrodes for Enhanced Stability and Photon Conversion Efficiency

The characteristics of two dimensional (graphene), one dimensional (single walled carbon nanotube incorporated poly(3,4-ethylenedioxythiophene):polystyrene sulfonate, composite) and zero dimensional (ZnO quantum dots) nanostructures have been systematically analyzed to elucidate the possibility of employing such nanostructures (transparent conducting corrosion resistant (TCCR)) for the passivation of the surface of a photoelectrode. Thin layer of graphene, carbon nanotubes embedded on a conductive polymer matrix (PEDOT:PSS) and ZnO quantum dots are incorporated on the surface of photoelectrode namely 'In' rich CuInS2 (ICIS) to act as corrosion resistant layers. The TCCR layers are found to be effective in inhibiting the surface recombination of charge carriers. Graphene exhibits a higher tendency towards the suppression of surface recombination across electrode-electrolyte interface, where an enhancement by a factor of 10(4) s is observed in the electron recombination life time. SWCNT/PEDOT:PSS composite films when employed as transparent conducting corrosion resistant layers enabled an enhancement of the cell stability by 95% when compared to unprotected 'In' rich CuInS2 electrode. The TCCR layers are found have a positive impact on the conversion efficiency of the photoelectrode and the maximum enhancement in the conversion efficiency achieved is 71% with ZnO quantum dot sensitized electrodes. (C) 2016 Elsevier Ltd. All rights reserved.