Application of Polymer Interlayers in Silicon-Carbon Nanotube Heterojunction Solar Cells

We explore the use of polymers as a conducting interlayer within silicon-carbon nanotube heterojunction photovoltaics. Three types of devices have been fabricated and characterized including silicon-carbon nanotube, silicon-conducting polymer and silicon-conducting polymercarbon nanotube. The conducting polymers studied were polyaniline, poly(3-hexylthiophene-2,5-diyl) and poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate). A thin conducting polymer interlayer significantly improves photovoltaic performance by creating a better depletion layer within the underlying silicon. With the addition of a top antireflection layer, a photovoltaic device, silicon-poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate)-carbon nanotubepoly(styrene) has been fabricated with a photovoltaic conversion efficiency of 8.7 %.