Berlin 2015 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 55: Inorganic/Organic Interfaces: Electronic Properties II

O 55.7: Vortrag

Mittwoch, 18. März 2015, 16:45–17:00, HE 101

Controlled photo-induced work function manipulation of the TCNQ/Au(111) interface — •David Gerbert and Petra Tegeder — Physikalisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Germany

One of the most important tasks to improve the performance of organic electronic devices is the development of deeper understanding and purposeful employment of metal electrode*s work function manipulation [1]. In the first layer TCNQ is known to be negatively charged on various metal surfaces [2,3], however only on Au(111) it is neutral [4]. We investigated the electronic structure of the TCNQ/Au(111) interface by means of two-photon-photoemission (2PPE) and observed a photo-induced work function shift of several hundred meV, which points towards photo-induced electron transfer from the gold substrate to the molecule. Interestingly the work function can be continuously tuned across the clean surface value which establishes new application possibilities of TCNQ as device-adapted hole-injection layer.

[1] N. Koch, ChemPhysChem. 8, 1438-1455 (2007).

[2] C. Park et al., Phys. Rev. B 90, 125432 (2014).

[3] T.-C. Tseng et al., Nat. Chem. 2, 374 (2010).

[4] I. Fernandez-Torrente et al., Int. J. Mass Spectrom. 277, 269-273 (2008).