Al-doped ZnO/Ag-nanowire Composite Electrodes for Flexible 3-Dimensional Nanowire Solar Cells

Silver nanowires in conjunction with sputter-coated Al-doped ZnO (AZO) thin films were used as a composite transparent top electrode for hybrid radial-junction ZnO nanowire/a-Si:H p-i-n thin-film solar cells. Solar cells with the composite nanowire top contacts attained a short-circuit current density (J_sc) of 13.9 mA/cm² and a fill factor (FF) of 62% on glass substrates while a J_sc of 13.0 mA/cm² and FF of 62% was achieved on plastic substrates. The power conversion efficiency (PCE) of the 3-dimensional solar cells improved by up to 60% compared to using AZO electrodes alone due to enhanced coverage of the top electrode over the 3-D structures, decreasing the series resistance of the device by 5×. The composite layer also showed a 10× reduction in sheet resistance compared to the AZO thin-film contact under applied mechanical strain.