(585g) Three Dimensional Photovoltaic Microyarns with Efficient Optoelectronic Performance and Enhanced Exciton-Hole Pair Separation

The solar energy conversion efficiency of flat dye-sensitized solar cells (DSC) could reach up to 12.1% using platinized transparent conductive oxide (TCO) positive electrodes/support materials. Highly interaligned carbon nanotubes (CNTs) demonstrate excellent mechanical, electronic, and catalytic properties, which exhibit high surface area with enhanced optoelectronic and electronic performance. A yarn-shaped and high efficiency DSC has been developed using coaxial, inter-alighned, ultrastrong and highly conductive CNT yarns (CNY) in both electrtodes with solid state electrolyte. The hydrothermally crystalized TiO₂ film along with a thin (50-100nm) underlayer interfaced with the high surface area CNY has been grafted around the working electrode (WE), which has been found capable in wide range of structural flexibility (30-330⁰) without changing photovoltaic characteristics. The maximum photoconvesion efficiency achieved is 6.15%, which is independent of incedent ilumination and cell shape or posision. Due to the yarn shape, the CNY cells can easily be woven to engineering textile, which may be used in wide field of practical application, such as portable/embedable intrisic photosensor, 3D photovoltaics, clothing with integrated photovoltaic yarns etc. This innovative solid state, 3D and low cost CNY based photovolatic yarn opens a new era of high efficiency 3D flexible solar cells.