Light Management for Solar Fuel Technology

Micro and nano-optical designs have resulted in a wide range of approaches for enhancing light harvesting in solar fuels by either improving absorption in the light absorber or reducing shadow loss from catalysts. Three main categories include structuring in the semiconductor, modifying interfaces with proper dielectric configuration, and manipulating light with metallic media. In this presentation, I will talk about a few strategies. Introducing multi-radii or nanocone shapes allows broadband absorption. High-n and low-k dielectric nanoconical waveguides can prevent the catalyst layer from blocking light. Arrays of micron-scale triangle metal grids can redirect the incoming light to reduce the shadow loss. Metal nanoparticle catalysts with plasmonic resonance shifting the UV region can minimize parasitic absorption and reflection losses. In addition, plasmonic nanostructures that can harvest visible light and generate non-equilibrium hot carriers capable of catalyzing chemical reactions are an innovative platform to be explored.

Speaker Biography
Wen-Hui (Sophia) Cheng received her B.S. and M.S. degrees from National Cheng Kung University, Taiwan, and pursued her Ph.D. from Caltech, all in Materials Science. During her Ph.D. research under the guidance of Prof. Harry Atwater, she focused on mesoscale design of photoelectrochemical fuel cells as part of the Joint Center of Artificial Photosynthesis (JCAP). Afterward, she joined Professor Dionne’s group as TomKat Postdoctoral Fellow at Stanford University. She has extensive experience with semiconductor nanofabrication, material characterization, optical simulations, and device physics. She has made an integrated device for splitting water with sunlight to make hydrogen fuel. She also demonstrated a gas diffusion electrode for CO₂ reduction to generate CO from solar energy, both with record efficiencies at the time. These efforts have been honored with the MRS graduate student silver award and the Dow sustainability innovation student challenge award. She is now an Assistant Professor in the Department of Materials Science and Engineering at National Cheng Kung University in Taiwan. Her research interests include manipulating light to assist chemistry for energy applications and engineering structures for optoelectronics as a material scientist.