X-ray induced ultrafast charge transfer in thiophene-based conjugated polymers controlled by core-hole clock spectroscopy

Abstract

We explore ultrafast charge transfer (CT) resonantly induced by hard X-ray radiation in organicthiophene-based polymers at the sulfur K-edge. A combination of core-hole clock spectroscopy withreal-time propagation time-dependent density functional theory simulations gives an insight into theelectron dynamics underlying the CT process. Our method provides control over CT by a selectiveexcitation of a specific resonance in the sulfur atom with monochromatic X-ray radiation. Our combinedexperimental and theoretical investigation establishes that the dominant mechanism of CT in polymerpowders and films consists of electron delocalisation along the polymer chain occurring on the low-femtosecond time scale.