Fabrication and Electrochemical Photovoltaic Response of CdSe Nanorod Arrays

CdSe nanorod electrode arrays with the nanorods aligned normal to the substrate were fabricated using porous aluminum oxide (PAO) templates. Photovoltaic characteristics were determined electrochemically in an aqueous solution using polysulfide (S-n(2-)) as the redox mediator. Isolating the back electrode from the electrolyte with a 100-nm-thick TiO2 barrier layer increased the open circuit voltage from -0.23 to -0.34 V and the fill factor from 0.42 to 0.57. Depending on the electrolyte concentration, IPCE values between 2.5 and 8% were observed at an incident wavelength of 500 nm. Internal quantum efficiencies were estimated to approach 50%. This architecture could be beneficial for the fabrication of bulk-heterojunction photovoltaic devices in conjunction with solution-deposited semiconducting inorganic nanoparticles or organic semiconductors.