We present a combined experimental and computational density functional theory (DFT)/time-dependent DFT study of the geometry, electronic structure and optical absorption spectrum of the solar-cell sensitizers cis-[Ru(4,4′-COO--2,2′-bpy)2(X) 2]4- (X = NCS, Cl) in water solution. The experimentally observed red-shift of the spectrum upon substitution of NCS-by Cl-is well reproduced by our theoretical model and appears to be related to stabilization of the t2g-π* HOMOs in the NCS- complex. The π* LUMOs of the Cl complex are destabilized by a smaller extent with respect to the HOMOs, due to the increased π-back bonding interactions with the bipyridine ligands.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry