Thursday, February 16, 2012
10:45 am Maryland Hall

Yan Yao
Stanford University

Title: “Nanostructure Design for Efficient Energy Devices”

Efficient energy conversion and storage play important roles in the renewable energy landscape. In developing next-generation high-performance and low-cost batteries and solar cells, significant challenges exist at both the fundamental and practical levels. In this talk, I will discuss how nanostructure design can provide us a unique opportunity to manipulate the electrons, ions and photons to obtain remarkable device performance. In the first example, I will demonstrate a new approach to broad-band light trapping by forming whispering-gallery resonant modes inside a spherical nanoshell structure. Using nanocrystalline silicon as a model system, the absorption of a single layer of 50-nm-thick spherical nanoshells is equivalent to a 1-um-thick planar nc-Si film. Then I will show lithium-ion battery anodes made of interconnected hollow spherical structure are capable of accommodating large mechanical strain without pulverization. The structure design is theoretically guided to effectively reduce lithium-diffusion-induced stress and experimentally verified with long electrochemical cycling life.  Finally, I will show the approaches of nanoscale morphology engineering leading to efficient polymer solar cells.

Nano and Micro Technology

Cell and Molecular Biotechnology

Interfacial Phenomena

Computational Biology and Functional Genomics

Molecular Thermodynamics

Drug Delivery, Biomaterials, and Tissue Engineering