When 11:45 AM - 1:00 PM Apr 21, 2009
Where 2150 HH Dow
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Hybrid Functional Materials for Photonics and Photovoltaics

Jongseung Yoon, University of Illinois

In the first part of my talk, I will present our recent work that explores techniques to exploit silicon in unusual photovoltaic modules. Silicon, in amorphous or various crystalline forms, is used in >90% of all installed photovoltaic (PV) capacity. The high natural abundance of silicon, with the excellent reliability and good efficiency of solar cells made with it, suggest its continued use, on massive scales, for the foreseeable future. As a result, although there is significant promise for organics, nanocrystals, nanowires and other new materials for photovoltaics, many opportunities continue to exist for research into unconventional means for using silicon in advanced PV systems. We developed arrays of monocrystalline Si solar microcells for modules with ultrathin, flexible, semitransparent, and micro-optic concentrator designs. The resulting devices can offer unconventional and useful features, including high degrees of mechanical flexibility, user-definable levels of transparency, and ultra-thin form factor micro-optic concentrator designs, together with the potential for high efficiency and low cost.

In the second part of my presentation, I will discuss block copolymer photonic crystals from self-assembled tunable reflectors to lasing and sensing elements. Block copolymers have proven to be a unique materials platform for easily fabricated large-area photonic crystals. One-, two-, and three-dimensional photonic crystals have been demonstrated over the past decade with various microdomain structures created through microphase separation of block copolymers. On the basis of successful introduction as passive photonic platforms, we extended our interest of these materials towards realizing active optical elements. In the second part of my talk, I will describe the utilization of block copolymer photonic crystals for creating self-assembled active optical elements such as photonic microcavity for optically driven lasing, and stimulus responsive self-assembled reflectors for chemical, thermal, and mechanical sensing.