Nanostructured Photovoltaic Cells Fabricated with Porous Aluminum Oxide Templates

Semiconducting polymer photovoltaic cells are good candidates as new materials for solar cells because they are more flexible, cost-effective, and more compatible with traditional mass production techniques than those made from silicon. Polymer photovoltaic devices rely on exciton diffusion of photogenerated excitons to an interface where charge separation occurs due to offset energy bands. Nanoscale interpenetrating junction networks can prevent the recombination of excitons before they reach the interface. The goal of this project is to combine inorganic nanorods (CdSe) with a semiconductor polymer (P3HT) to make photovoltaic devices by using porous aluminum oxide (PAO) templates as the structural directing agent. Highly ordered porous aluminum oxide was prepared by using a two-step anodization procedure of electropolished aluminum plates. Next, a TiO2 layer and an additional metal layer (such as gold or titanium) were evaporated onto the PAO after removing extra aluminum from the periphery and back side of the templates. We then deposited CdSe nanorod electrode arrays onto the PAO templates. The structure of CdSe half solar cell was examined under a scanning electron microscope (SEM) to verify the precise dimensions of the CdSe nanorods. Photovoltaic characteristics were determined electrochemically in an aqueous solution using polysulfide (Sn2-) as the redox mediator. The effect of the TiO2 layer and the different metal layers were studied.