Judges’ Queries and Presenter’s Replies

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Presentation Discussion

  • May 21, 2012 | 11:16 p.m.

    Good work on your poster. It was very informative. Even though its not my field, I think you did a nice job with your explanation.

    I guess the main question I had is the following. What is the main take away message? You could restate this question by asking: what was the objective or hypothesis that your poster tried to address? Finally, if you combine all your results into a story, how is improved efficiency achieved?

  • Icon for: Michele Guide

    Michele Guide

    May 22, 2012 | 03:07 p.m.

    I would say the common thread is that we are all studying structure-property-function relationships in materials, and in these very interdisciplinary fields, it’s like a feedback loop. We focus on different aspects of synthesis, device fabrication or characterization and take what we learn from our individual studies to feed into the whole cycle. If I determine through nanoscale characterization that I need a fullerene with a certain physical structure to induce a certain type of morphology in a bulk heterojunction solar cell, then JJ gets some useful information about what kind of fullerene syntheses he may want to focus on. Then I work with those new materials and the cycle continues. We take an accumulation of fundamental physical and chemical lessons to accomplish the very practical goal of improved efficiency.

  • May 22, 2012 | 12:17 p.m.

    This is not my area of expertise but looks like an excellent set of projects that could really make a difference in this world. Improving energy efficiency with resources that are not limiting is a key challenge we face as a nation, as well as globally. Good luck with your projects!

  • Icon for: Michael Haibach

    Michael Haibach

    May 22, 2012 | 05:39 p.m.

    Nice Is YAG:Ce available/cheap enough to be used on the home-lighting scale? How much of a concern is the cost of the new phosphor materials that you are designing?

  • Small default profile

    William Paxton

    May 29, 2012 | 02:24 p.m.

    Great job!

  • Further posting is closed as the competition has ended.

  1. Kristin Denault
  2. http://www.igert.org/profiles/4714
  3. Graduate Student
  4. Presenter’s IGERT
  5. University of California at Santa Barbara
  1. John Cowart
  2. http://www.igert.org/profiles/4767
  3. IGERT Alum
  4. Presenter’s IGERT
  5. University of California at Santa Barbara
  1. Nathan George
  2. http://www.igert.org/profiles/3897
  3. Graduate Student
  4. Presenter’s IGERT
  5. University of California at Santa Barbara
  1. Michele Guide
  2. http://www.igert.org/profiles/4757
  3. Graduate Student
  4. Presenter’s IGERT
  5. University of California at Santa Barbara

Efficient Energy Conversion - From Understanding to Application: Organic Photovoltaics and Solid State Lighting

Organic photovoltaics (OPVs) and solid-state white lighting are interesting and demanding areas of research as they both offer tremendous benefits to our environment and to our economy in these energy conscious times. OPVs use organic polymers or small organic molecules to absorb radiation from sunlight and convert the energy into electrical current. Made from earth abundant materials that can easily be solution processed at low temperatures, they provide a lost cost, flexible, renewable energy option that can provide power to all regions of the world, especially remote areas that cannot be easily connected to a power grid. Yet efficiencies and lifetimes of OPVs need to be improved before they can become a viable option for large-scale power generation. Solid-state white lighting, which uses a phosphor in conjunction with a blue or near-UV InGaN LED to produce white light, has many benefits over traditional incandescent and fluorescent lighting sources such as high efficiencies, low energy consumption, long lifetimes and a mercury-free design. One of the most efficient and widely used phosphors is the yellow emitting Y3Al5O12:Ce3+ (YAG:Ce), yet the origins of its high efficiency remain unknown. YAG:Ce is not the ideal phosphor though, it suffers from thermal quenching of luminescence at elevated temperatures and lacks strong representation in the red spectral region leading to a low color rendering. The phosphor research is therefore two-fold: to elucidate the origins of the high efficiency in YAG:Ce while using this understanding to strategically design new phosphors with optimal characteristics for solid state white lighting.