Fall 2010 IAB
September 15 to 17
New Architectures for Efficient Photoelectrochemical Solar-to-fuel Conversion
In the past few years, the demonstration of new nanostructured templates for photoelectrochemical devices has been a key topic of interest for making efficient and competitive alternatives for efficient solar-to-fuel conversion. In this work, we highlight two unique approaches toward fabricating such device architectures using both top-down and bottom-up approaches. In the first case, we demonstrate the transformation of planar InP into anti-reflective InP nanopillar arrays by utilizing self-assembled SiO2 monolayers combined with a dry etch process. This results in a device architecture that, when combined with a Pd catalytic nanoparticle layer, leads to an approximate three times enhancement in photogenerated current density compared to planar InP. In the same spirit, we also demonstrate the fabrication of anti-reflective back-contacts for solar devices utilizing a generalized approach of solution-phase processing of vertically aligned carbon nanofiber arrays, and coating these highly conductive structures with semiconductor. To demonstrate the effectiveness of this technique, we utilize atomic layer deposition to coat TiO2 layers on this framework, and emphasize a similar 2-3 times enhancement to measured photocurrent. This work demonstrates two general routes to fabricating efficient photoelectrochemical devices that could be generalized to a variety of semiconductor materials.