Understanding the Design and Conduction of Materials for Organic Electronics at the Molecular Level

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This project is jointly funded by the Electronic and Photonic Materials Program (EPM) in the Division of Materials Research (DMR) and the Chemical Structure, Dynamics and Mechanisms Program (CSDM) in the Division of Chemistry (CHE).Technical Description: Organic materials as alternates to standard silicon-based semiconductors are fast becoming viable in areas of flexible electronics, sensors and photovoltaics. However, the physical mechanism by which charge transfer occurs in relation to the chemical structure in these systems is not well understood. In this project, important architectural elements of polymers that exhibit the best performance in organic electronics and photovoltaics are dissected to their molecular analogues to study their electronic and photo-induced transport characteristics at the single-molecule level. A series of oligomeric thiophenes are analyzed as analogues of polythiophene and its derivatives to understand the transport characteristics as a function of chemical structure. The scanning tunneling microscope-based break-junction technique is used to measure single-molecule charge transport characteristics and to probe photoconductivity in single-molecule junctions. Finally, analysis to correlate results from single-molecule transport measurements to bulk organic semiconducting device characteristics is used, enabling a multi-scale approach to understanding structure and function of efficient organic semiconductors. Through a combination of synthesis and measurements at the single-molecule level, this project provides molecular design rules for the development of novel materials used for organic electronics and photovoltaics.Non-technical Description: There is a need to understand the governing factors enabling the development of organic semiconductor materials with advanced transport properties to complement their inorganic counterparts. This project bridges the gap between the single-molecule electronic structure components of polymeric semiconductors that exhibit high mobilities and photovoltaic characteristics. Using the fundamental understanding gained from single-molecule experiments enables the design of a new class of materials, which are tested in single molecule junctions as well as device architectures. In addition to developing new compounds that impact organic electronics, an integral part of the project introduces interdisciplinary science to high school, undergraduate and graduate students, aiming to instill a desire to pursue careers in science. The nature of the project requires a close collaboration between the graduate students in the Venkataraman and Campos groups, from Applied Physics and Chemistry. A focus of the PIs is also to recruit undergraduate women and/or minority students to participate in the research and prepare them as competitive applicants for graduate school in the sciences. Finally, basic concepts in organic electronics are adapted for demonstrations at schools in Manhattan.