Keywords: Grä, tzel solar cells, dye–sensitised solar cells, conductive nanowires, indium zinc oxide, open–circuit voltage decay, OCVD, anodic aluminium oxide, AAO, templated growth, core–shell photoanodes, vertical nanowire arrays, nanotechnology, semiconductive shells
Conductive nanowires coated with a semiconductive shell as the photoanode in dye–sensitised solar cells
Dye–sensitised solar cells (DSSCs) based on indium–doped ZnO (IZO) core/TiO2 shell nanowires are fabricated using anodic aluminium oxide (AAO) templates. Polarisation characteristics are used to evaluate overall DSSC performance as a function of titania shell thickness while open–circuit voltage decay (OCVD) analysis elucidates the effect of shell thickness on both the order of the recombination and the lifetime of injected charge carriers. Overall DSSC performance properties, such as open–circuit voltage (Voc), short–circuit current (isc), fill factor (FF) and efficiency (η), correlate well with previously reported values as a function of shell thickness. OCVD measurements confirm that the nanowire morphology offers enhanced charge transport and transfer dynamics. The measurements show that both electron lifetime and electron recombination order are shorter for nanowire–based DSSCs (NW–DSSCs), implying that injected electrons are selectively swept away from the semiconductor–dye–electrolyte interface and collected more efficiently.