CAPTURING CHARGE TRANSFER DYNAMICS WITH ULTRAFAST TIME-RESOLVED XUV PHOTOELECTRON SPECTROSCOPY AT DYE - SEMICONDUCTOR INTERFACES

摘要

The ultrafast heterogeneous electron transfer at the interface between the N719 ruthenium dye complex and TiO_2 is studied by means of ultrafast XUV photoemission spectroscopy. After optical excitation of the system by a laser pulse of 530nm wavelength, XUV light obtained from high-order harmonic generation is utilized to probe the electron density distribution of the involved ground and excited states at the interface. By using a spectral decomposition of the transient emission signal we identified for the first time directly the absolute binding energies of the dye singlet and triplet metal-to-ligand charge-transfer states. The advantage of studying simultaneously injection kinetics and the electronic band alignment will be discussed and an outlook for future applications of this method in view of other promising energy related materials will be presented.