Three dimensional (3D) structures such as nanowires, nanotubes, and nanorods have the potential to increase surface area, reduce light reflection and shorten charge carrier transport distances. Assembly of such structures thus holds great promise for enhancing photoelectrochemical solar cell applications. In this study, genetically modified Tobacco mosaic virus (TMV1cys) was used to form self-assembling 3D nanorod current collectors and low light reflecting surfaces. Photoactive CuO was subsequently deposited by sputtering onto these patterned nanostructures and examined for photocurrent activity. An assembled surface structure with period of ~500 nm, i.e. TMV1cys concentration at 10-3 mg/mL, was demonstrated to suppress light reflection from 13% down to 3% leading to a higher efficiency in the utilization of incident photons. CuO thicknesses of 520 nm on TMV1cys patterned current collectors produced the highest photocurrent density of 3.15 mA/cm2 yet reported for a similar sized CuO system. Thus the combined effects of reducing charge carrier transport distance, increasing surface area and the suppression of light reflection makes these virus assembled surfaces ideal for photoelectrochemical applications.
