Photoelectric Response from Nanofibous Membranes

Electrospinning has been used to prepare nanofibrous composite membranes of semi-conducting particles (TiO 2 ) and photovoltaic dyes. Electrospinning is a relatively simple technique where electrical forces are used on polymeric solutions to produce nanoscale fibers. The resulting nanofibrous membranes have surface areas that are roughly one to two orders of magnitude higher than conventional thin films. It is believed that this higher surface will allow for more efficient light harvesting in photovoltaic devices. Our research has focused on the fabrication of organic/inorganic hybrid solar cells featuring dye sensitized nanocrystalline semiconductor particles using electrospinning. Phthalocyanine and N3 (cisdi(thiocyanato)bis(2, 2’-bipyridyl-4, 4’-dicarboxylate) ruthenium(II)) photoactive dyes were electrospun with semi-conductive TiO 2 nanoparticles into a matrix polymer, polyacrylonitrile (PAN). Electron microscopy and elemental analysis of the electrospun membranes shows that each component is present and uniformly dispersed in the nanofibrous membranes. In general, the dye membranes electrospun with the TiO 2 nanoparticles exhibited a greater photoelectric response than the membranes with dye only. The N3 dye membranes however showed the greatest photoresponse in comparison to the phthalocyanine dyes, with or without the TiO 2 nanoparticles. Photoelectric responses on the order of 30 μA and 280 mV were achieved with dye-sensitized membranes and are believed to be the first demonstration of a photoelectric response from an electrospun nanofibrous membrane.