Research Abstracts Online
January 2009 - March 2010
University of Minnesota Twin Cities
Institute of Technology
Department of Chemical Engineering and Materials Science
PI: C. Daniel Frisbie
Tuning Charge-Transport Parameters in PTCDI Crystals
These researchers use density functional theory to illustrate how it is possible to control the charge-transport properties in perylene diimides (PTCDI) crystals as a function of the nature of substituents. End-substituted PTCDIs provide a unique test bed for models that aim at predicting and optimizing charge-carrier mobilities. Special attention has been paid to the study of the electronic properties of this large variety of crystalline structures by calculating their band-structure, density of states and effective masses for hole and electron transport. These calculations shows that chemical substitution strongly affects the bulk transport levels and the intermolecular electronic coupling of the PTCDIs, although do not change the electronic structure at the single molecule level.
Current work focuses on the investigation of the modulation of the transfer integrals due to thermal fluctuations on selected PTCDI crystals. The researchers are paying special attention to the study of how the short-axis and long-axis librations in the crystal affect both hole and electron transport. To this end, they combine molecular dynamics simulations and quantum-chemical calculations.
Demetrio da Silva Filho, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia
Maria Carmen Ruiz Delgado, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia