Theoretical approach for Fe(II/III) and its chlorophyll-related complexes as sensitizers in dye-sensitized solar cells

Dye is the key to efficiency of harvesting solar energy in dye-sensitized cells (DSSCs). The dye performances such as light absorption, electron injection, and regeneration depend on molecule structure. To predict it, one needs compute optimized geometry, HOMO level, LUMO density distribution, gaps, dipole moment ground excited state. Chlorophyll-related chlorin porphyrin, well their κ2O,O’ complexes with Fe(II/III), were investigated functional theory (DFT) time-dependent (TD-DFT) computations using B3LYP method def2-TZVP basis set. NPA charges also calculated know valence metal cations exactly. In general, calculations show that introduced occupied d orbitals lower oxidation potentials than chlorophyll ligand orbitals, which are responsible for emergence additional absorption bands. states result effective band broadening redshift spectrum absorbance expected improve DSSC performance.
 Another requirement has be possessed ability regeneration, moment. Fe(II) complex fulfilled these requirements, but not Fe(III) due having a low injection capability. However, this work shown exhibits non-innocence ligand. It results trivalent divalent state change, appearance radical cation, an extra hole, broader spectrum. can affect its other electronic properties, Thus, it considered attractive candidate sensitizer DSSCs