(304e) Accurate Excited States of Photovoltaic Molecular Systems from Long-Range Corrected TDDFT Methods

Authors: 
Wong, B. - Presenter, University of California, Riverside

The ability to tune electronic properties in molecular photovoltaics and nanomaterials holds great promise for incorporating these materials in next-generation transistors, circuits, and nanoscale devices. In particular, the use of predictive first-principles calculations plays a vital role in rationally guiding experimental efforts to optimize energy harvesting in nanoscale and mesoscale materials. In this presentation, I will highlight recent work in my group using new time-dependent quantum-mechanical approaches for understanding and predicting the electronic properties of photovoltaic molecular systems.

Most computational work on these light-harvesting materials have used conventional DFT functionals which leads to a severe underestimation of excitation energies in the charge-transfer states. We have addressed these serious issues by calculating excited state energies and properties using the long-range-corrected (LC) TDDFT formalism. Benchmark calculations for assessing the LC-TDDFT formalism are discussed, and a comparison to predictions by the widely-used B3LYP functional are also examined. Based on overall trends in excitation energies and properties, the LC-TDDFT formalism significantly improves the description of charge-transfer excitations in organic systems and enables a guided approach to maximizing the potential capabilities of future organic sensitizers.