Self-aligned carbon nanotubes yarns (CNY) with efficient optoelectronic interface for microyarn shaped 3D photovoltaic cells

An innovative solid state dye sensitized photovoltaic carbon nanotubes yarn (DSP-CNY) has been developed using thermally-stable and highly conductive carbon nanotubes (CNT) yarns (CNYs). These CNYs are highly inter-aligned, ultrastrong and flexible with excellent electrical conductivity, mechanical integrity and catalytic properties. The CNYs are coated with a dye-incorporated TiO2 microfilm and intertwined with a second set of CNYs as a counter electrode (CE). The DSP-CNYs were developed without using any metal wires or any expensive transparent conductive oxides (TCOs), liquid electrolytes, or glass or plastic cladding. The maximum photon to current conversion efficiency (ηAM 1.5) achieved with prolonged-time stability was 2.57%. The yarn-shaped flexible cells were able to transport photocurrent over a significant distance using a simple cell configuration with a wide range of structural flexibility (30–330°). These cells are capable of efficiently harvesting incident photons regardless of direction and generating photocurrents with high efficiency and long term stability.