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Title: The Frenkel exciton Hamiltonian for functionalized Ru(II)–bpy complexes

Journal Article · · Journal of Luminescence
 [1];  [2];  [1];  [3];  [1]
  1. Los Alamos National Laboratory (LANL), NM (United States). Center for Nonlinear Studies (CNLS) and Center for Integrated Nanotechnologies (CINT)
  2. Univ. of Washington, Seattle, WA (United States); Los Alamos National Laboratory (LANL), NM (United States). Center for Nonlinear Studies (CNLS) and Center for Integrated Nanotechnologies (CINT)
  3. Los Alamos National Laboratory (LANL), Los Alamos, NM (United States). Chemistry Div.

Electronic excitation energies and wavefunctions are calculated for Ru(bpy)3+2 (bpy=2,2'-bipyridine) and its two derivatives, where one or two bpy ligands are functionalized with carboxyl and methyl groups. We show that the structure of these molecules allows one to express their excitations in terms of wavefunctions localized on individual ligands via the Frenkel exciton model. The model is based on three parameters - effective single-ligand excitation energy, inter-ligand interaction coupling, and energy shift brought by the ligand functionalization - that are extracted from time-dependent density functional theory (TDDFT). This simple model is able to accurately explain the optical intensity, localization properties, and splitting patterns of the low-energy excited states not only in molecules with a high degree of symmetry, but also in non-symmetrically functionalized Ru(II) complexes in vacuum and in solvent. Such reduced description of the excited states provides better understanding and interpretation of experimental data on Ru–polypyridine complexes, and allows for description of excited-state structure in a large ensemble of interacting molecules and treatment of possible charge and energy transfer phenomena in the material.

Research Organization:
Energy Frontier Research Centers (EFRC) (United States). Center for Advanced Solar Photophysics (CASP)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
DOE Contract Number:
AC52-06NA25396
OSTI ID:
1065713
Journal Information:
Journal of Luminescence, Vol. 131, Issue 8; Related Information: CASP partners with Los Alamos National Laboratory (lead); University of California, Irvine; University of Colorado; Colorado School of Mines; George Mason University; Los Alamos National Laboratory; University of Minnesota; National Renewable Energy Laboratory; ISSN 0022-2313
Publisher:
Elsevier
Country of Publication:
United States
Language:
English