This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).
The objective of this research is to acquire a better understanding of the charge transfer that takes place at the interfaces between organic semiconductors and metal, over a broad range of disorder in the organic material. This charge transfer strongly affects the electrical properties of such interfaces, which are critical to organic transistors, light-emitting diodes, and photovoltaic devices. The approach is to perform three types of measurements (nanoscale electronic transport; alternating current scanning tunneling microscopy; and terahertz time-domain spectroscopy) on three of the most technologically relevant materials systems. By combining data from these complementary techniques, and working with theorist collaborators, a systematic knowledge of the charge transfer and energetic alignment in these systems will be acquired. The intellectual merit of this project is that it would improve understanding of device physics that is essential for optimization and establishing the limits of organic device performance. Simultaneously, these issues involve some of the most challenging questions in condensed matter physics. Combining the expertise of the PIs will lead to new experimental techniques that span from the nanoscale to the macroscopic and from DC to the THz frequency regime. The broader impacts of this project are threefold. First, the insights into these issues may have direct impact on commercial applications of organic semiconductors, including photovoltaics and lighting. Second, the project will support the research training of two graduate students, as technical workforce development. Third, the PIs will use outreach opportunities to educate the broader community about organic semiconductors and related technologies.
