Title: Organic-Inorganic Interfaces and Hole Trapping in Solids with Hybrid Density Functional Theory

Speaker: Na Sai, University of Texas

Date/Time: Tuesday, February 22, 2011, 10:00 am MST       

Location: CSRI Building/Room 90 (Sandia NM)

Brief Abstract: Density functional theory (DFT) with local or semilocal functionals has been successful in a wide range of applications. Several important problems, however, including the calculation of the band gap in solids, and the treatment of systems involving fractional charges, challenge the DFT. We have applied a hybrid density functional method to study organic molecular solids and interfaces that are relevant for photovoltaic applications. These calculations provide us with a better description of interfacial band offsets and allow us to understand the dependence on molecular orientation. We also examine hole trapping in organic molecular crystals with a computational scheme that is based on the tuning of the fraction of exact exchange in hybrid DFT. These calculations allow us to predict the formation of self-trapped hole polarons in perfect molecular crystals and identify why standard functionals fail to describe localized states in solids.

CSRI POC: Rudy Magyar, (505) 844-8343