Cu(I)-Based Sensitizers Featuring 6,6 '-Dimethyl-4,4 '-Dicarboxylate-2,2 '-Bipyridine With Functionalized 2,9-Dimethyl-1, 10-Phenanthroline Ligands: A Structural, Electronic And Spectral Investigation

A series of heteroleptic Cu(I)-based complexes featuring 6,6'-dimethyl-4,4'-dicarboxylate-2,2'-bipyridine (dmd-cbpy) with functionalized 2,9-dimethy1-1,10-phenanthroline (dmp) ligands are investigated by density functional theory (DFT) and time-dependent DFT (TD-DFT). Molecular geometry, electronic structure, and absorption spectral property are predicted in dichloromethane (CH2Cl2) solution. Our results show that increasing pi-conjugation and heteroaromatic groups to ancillary dmp ligand would decrease HOMO-LUMO gap, broaden spectral cover range, boost absorption intensity, enhance light-harvesting efficiency (LHE), and thus improve the absorption spectral properties. Structural optimization on dmp ligand has comparable influence on the electronic structure, spectral property, and LHE of Cu(I)-based complexes featuring dmp and bpy ligands relative to those featuring double bpy ligands. This work highlights that heteroleptic Cu(I)-based sensitizers with more efficient functionalized groups would provide potential application prospect in DSSCs.