Self-assembled Carbon Nanomaterial Scaffolds for Efficient Energy Device Applications

Cary Pint, University of California, Berkeley

Thursday, April 14, 2011

This seminar is part of the Jones Seminars on Science, Technology, and Society series

One of the greatest challenges facing mankind in the next century is energy management amidst a finite and limited amount of energy resources. As future energy shortages will be catalyzed by rapid urbanization and population rise, the search for a "new oil," or an equally cost-effective alternative energy source, is important to facilitate modern societal and technological development. The purpose of the research presented here is to utilize nanoscale carbon-based material templates as new architectures for highly efficient energy storage and energy harvesting devices. This work begins by demonstrating techniques geared toward generating templates of single-walled carbon nanotubes transferred to conductive substrates. This is accomplished using both a Gecko-inspired transfer process as well as a high-temperature metal sintering process, as the latter facilitates robust metal-SWNT electrical interfaces. This enables device architectures benefiting from the single-molecule SWNT properties inherent in such self-assembled materials. From this material, I will discuss the fabrication of a new class of solid-state supercapacitors that are ideally suited for both high power density and high energy density. Additionally, I will discuss approaches to utilize carbon nanofiber (CNF) arrays grown on conductive substrates for efficient photoelectrochemical solar-to-fuel conversion devices. Solution-phase processing of CNFs using tunable elastocapillary forces yields ideally textured 3-D solar device back-contact architectures. Utilizing this architecture with TiO2 as a model semiconductor absorber, device performance metrics are enhanced by up to three times compared to planar device architectures due to structurally driven enhancements to carrier collection. Similar material frameworks fabricated using InP and top-down processing techniques emphasize the route toward high efficiency 3-D device architectures, with efficiencies measured up to 8% for H2O reduction. This work gives a roadmap toward ways in which efficient carbon nanomaterial architectures can be engineered at the growth level to be integrated into diverse and efficient energy applications promising for affordable next-generation energy storage and harvesting systems.

About the Speaker

Dr. Cary L. Pint is a postdoctoral fellow at University of California, Berkeley involved in research focused on new solar energy device fabrication. He received his Ph.D. at Rice University in 2010 with research focused on the controlled growth of self-assembled single-walled carbon nanotubes and their use in applications ranging from sensing devices to energy storage devices. Cary has authored over 30 publications, is a coauthor on a book focused on carbon nanotube synthesis and applications soon to be published, and has been the recipient or finalist for a number of national awards, including the APS LeRoy Apker award, the Vanderbilt Prize, and recently the AVS Dorothy and Earl Hoffman Scholarship.