Impact of interface-state formation on the charge-carrier dynamics at organic-metal interfaces
Abstract
We study the role of electronic interface states on the electron transfer dynamics between layers of the organic semiconductor 3,4,9,10-perylene-tetracarboxylic acid dianhydride (PTCDA) and the (111) and (100) surfaces of silver. For this purpose, we investigate the change of the decay dynamics of the first (n = 1) image-potential state on these surfaces upon adsorption of an ordered monolayer of PTCDA by means of time-resolved two-photon photoemission (2PPE). We find that the already short lifetime of the (n = 1)-state on Ag(111) is only slightly further reduced by PTCDA adsorption, whereas a much stronger reduction by a factor of three is observed for adsorption on Ag(100) resulting in similar lifetimes for both orientations. We show by model calculations on the basis of an analytical one-dimensional pseudo-potential that the enhanced decay for PTCDA/Ag(100) can be attributed to the opening of an additional channel for electron-electron scattering by the formation of an interface state which is derived from the Shockley-type surface resonance of Ag(100).
- Publication:
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New Journal of Physics
- Pub Date:
- September 2020
- DOI:
- 10.1088/1367-2630/abb0c3
- Bibcode:
- 2020NJPh...22i3042M
- Keywords:
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- metal-organic interfaces;
- charge-transfer dynamics;
- image-potential states;
- time-resolved two-photon photoemission