2009-10-15
What's going on down there? Insights into fundamental processes in organic electronic materials and devices from electric force microscopy.
Fabricating circuits and solar cells by solution-processing readily available organic compounds is a potentially revolutionary concept. Given the meager understanding of organic semiconductor materials, however, development of organic devices proceeds largely by trial and error. While tremendous effort is being expended to mass-produce organic devices, almost no attention has been devoted to developing a microscopic understanding of fundamental processes in organic semiconductors. To accelerate development, we need a better microscopic understanding.
We use electric force microscopy to make local measurements of electrostatic potential and capacitance in working organic devices. Measurements take place with devices in vacuum or in nitrogen, and in some cases over a large temperature range and under variable-wavelength irradiation. The resulting data has allowed us to address long-standing puzzles related to ion motion, metal-to-organic charge injection, and charge trapping in organic semiconductor materials. Case studies involving both small-molecule and polymeric semiconductors will be presented.
The ability to characterize organic material at nanometer spatial resolution with chemical specificity lags far behind the ability to synthesize new materials and make devices. I will briefly present my group's work to develop scanned-probe approaches to detecting magnetic resonance and electric field fluctuations at nanoscale resolution.
For more information about Prof. Marohn's research, visit the Marohn Lab webpage.
