Solid state dye-sensitized photovoltaic micro-wires (DSPMs) with carbon nanotubes yarns as counter electrode: Synthesis and characterization

Innovative all solid state dye-sensitized photovoltaic micro-wires (DSPMs) have been developed using low-cost, thermally-stable and highly conductive titanium micro-wires and carbon nanotubes yarns (CNYs). Highly inter-aligned, ultrastrong and flexible CNYs with excellent electrical conductivity, mechanical integrity and catalytic property have been successfully used as counter electrodes (CEs). The open circuit voltage and current density of the DSPMs can remarkably be improved through optimizing the numbers of CNYs and CNYs–TiO2 interface. Optimizing the number of CNYs in the CEs yields a photoconversion efficiency of 0.1959% with prolonged-time stability. The DSPMs were made without expensive transparent conductive oxides (TCOs), liquid electrolytes and glass or plastic cladding. The DSPMs are able to transport photocurrent over a significant distance using a simple cell configuration with a wide range of flexibility (10–180°). These cells are capable of efficiently harvesting incident photon from any direction and generate photocurrent with an efficient reproducibility throughout a large number of illumination on–off cycles.