Biography
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.. image:: Dwyer.jpg
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   :target: http://marohn.chem.cornell.edu/About/Dwyer.htm

I am a second year graduate student in the department of Chemistry and Chemical Biology studying physical chemistry. I grew up in Delafield, Wisconsin, outside of Milwaukee. From an early age, I have been attracted to building models and making predictions.  As an avid sports fan, I often wanted to predict the performance of my hometown Green Bay Packers and Milwaukee Brewers. I found it fascinating to look at how well or poorly simple models can explain complicated human performance, and I learned a lot more about sports by examining the successes and failures of these models.

Physical chemistry was a natural extension of this interest; for the same reason I enjoy trying to model how the Green Bay Packers will do next year with a simple spreadsheet, I also enjoy trying to relate the complex data from an experiment to simple models. I find the failures of these models can be particularly interesting; for example, in high school chemistry, I tried adding the masses of protons and electrons to determine the mass of an atom and discovered that this didn't work!  I was astonished how a simple math problem revealed a surprising hole in the conservation of mass model we had learned.

I attended college at the University of Notre Dame, where I majored in Chemistry and Theology. At Notre Dame, I did research on quantum dot solar cells, which solidified my interest in physical chemistry. Afterwards, I wanted to learn more about how and why potential solar cell materials work well or poorly on a microscopic level. At Cornell University, I joined the group of Dr. John Marohn because of his group's research into the factors that limit the efficiency of organic solar cell materials. In my free time, I still enjoy playing, watching and making statistical models of sports such as baseball, football, tennis and golf.


Research
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.. figure:: Cantilever.png
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   A cartoon of a charged tip near a sample, with an actual tip for comparison. About 10,000 tips would span the width of a human hair. Copyright 2011, `American Chemical Society`_.

	.. _`American Chemical Society`: http://dx.doi.org/10.1021/jp207387d

Commercial solar cells and other electronic devices are typically made of silicon. Silicon solar cells, however, are energy-intensive to manufacture and must be thick because they don't absorb light very well. Organic "plastic" solar cell materials are an alternative that could be cheaply, and less energy intensively, printed using inkjet printer technology onto very thin materials—imagine a roll of plastic wrap that was also a solar cell.

The best plastic solar cells, however, are less than half as efficient as silicon solar cells. In principle, one of the advantages of plastic materials is that we can make plastics with a wide variety of different properties: different colors, flexibilities, hardnesses, etc. Unfortunately, we don't yet have a clear idea of what types of plastics we should be trying to make to improve solar cell efficiency. Unlike silicon solar cells, which are very well understood, we don't know what factors are limiting the efficiency of plastic solar cells.

To better understand what limits plastic solar cell efficiency, my research uses electric force microscopy to study how charges move through plastic solar cell materials. Unlike a typical microscope, which uses light to make an image, an electric force microscope uses a tiny, sharp, charged tip to feel the charges in a plastic solar cell material. We move the tip across the surface of the material to collect an image of the charges in the material, in the same way a person reads Braille by moving her finger across the page. The more detailed information in these charge images helps us understand why a particular solar cell material is not more efficient.