Designed Growth of Photovoltaic Nanowire Arrays on Patterned Substrates

The efficiency of solar cells relies heavily on the materials chosen to absorb solar radiation and also on design of the cells. While material composition plays a fundamental role in defining the extent of solar light absorption, the nanostructured morphology plays a decisive role in increasing efficiency of the device. We have developed a novel technique to grow nanowire arrays on conducting substrates by simple bottom-up method. The approach has been tested with CdTe, one of the most potential alternatives to Si-based solar cells. CdTe nanowires with uniform diameter were grown over large area by electrodeposition on lithographically patterned nanoelectrodes embedded in a polymer matrix. The photocurrent obtained from this nanowire device was comparable to that obtained from a CdTe film of much higher area. Our technique outlines a simple approach to obtain designed periodic arrangement of the nanostructured light absorbers which is very crucial for designing efficient solar cells.