Polarization-dependent X-ray absorption spectroscopy is combined with density functional calculations and atomic multiplet calculations to determine the crystal field parameters 10Dq, Ds, and Dt of transition metal phthalocyanines and octaethylporphyrins (Mn, Fe, Co, Ni). The polarization dependence facilitates the assignment of the multiplets in terms of in-plane and out-of-plane orbitals and avoids ambiguities. Crystal field values from density functional calculations provide starting values close to the optimum fit of the data. The resulting systematics of the crystal field can be used for optimizing electron-hole separation in dye-sensitized solar cells.
Journal of Chemical Physics, 2014, Vol 140, Issue 11
Density functional theory; Nitrogen compounds; Polarization; Single crystals; Solar cells; X ray absorption spectroscopy; Crystal field parameter; Crystal fields; Dye-Sensitized solar cell; Electron-hole separation; Metalphthalocyanines; Octaethylporphyrins; Out-of-plane; Polarization dependence; Beryllium compounds; PORPHYRINS