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|2011 Graphene Session, Grenoble, France|
|Microelectronics Research Center|
|Electrical and Computer Engineering|
|The University of Texas at Austin|
|Co-President, Engineers Without Borders - USA, Greater Austin Chapter
Secretary, Engineers Without Borders - USA, South Central Region
|Sampling and Measurement|
My PhD research has primarily focused on novel measurement techniques to probe mechanisms of charge transport and recombination in organic bulk heterojunction (BHJ) solar cells. Most researchers use a typical vertical device structure to study transport in organic photovoltaic (OPV) cells but this structure has many limitations. Instead, we have developed a lateral structure where we can study charge carriers traversing OPV devices of various lengths. The variation in device length has given us the ability to measure the mobility-lifetime product and generation rate of charge carriers in these devices. The mobility-lifetime product in OPV cells is the primary figure of merit to characterize the movement of charge carriers BHJ solar cell devices. Additional studies to determine the effect of light intensity, light spectrum, electric field, and temperature on the mobility-lifetime product have begun to provide insight on recombination mechanisms, the mobility of the charge carrier, and the carrier's lifetime. The incorporation of additional measurement techniques on lateral solar cell devices is also planned to further probe transport and recombination mechanisms in these materials.
In addition to transport studies, we have begun to work with a small business to develop inkjet printable OPV cells on flexible substrates. These OPV cells will provide power to a wireless communication system and other microelectronic devices based on a inkjet printable architecture. Currently, we are optimizing commercially available materials and device architectures in order to integrate the OPV cell and the communication system into a fully automated manufacturable process that is compatible with flexible electronic systems.
Copper indium diselenide (CIS) and a related material copper indium gallium selenide (CIGS) have been actively researched for over 20 years and researchers have made solar cells with efficiencies nearing 20%. In order to reduce the cost of these materials and add potential for commercialization, we have collaborated with a group that synthesized CIS nanoparticles from solution. Transport studies of nanoparticle films of CIS reveal variable range hopping transport in this material. In addition to transport studies, solar cells based on CIS nanoparticles have been fabricated and have exhibited efficiencies currently exceeding 3%.
Conference Publications and/or Presentations