Impact of fluorination on interface energetics and growth of pentacene on Ag(111).

Ingo Salzmann,Frank Schreiber,Alexander Gerlach,Steffen Duhm,Meng-Ting Chen,Thomas Geiger,Holger F. Bettinger,Bin Shen,Antoni Franco-Cañellas,Qi Wang

doi:10.3762/bjnano.11.120

Abstract

We studied the structural and electronic properties of 2,3,9,10-tetrafluoropentacene (F4PEN) on Ag(111) via X-ray standing waves (XSW), low-energy electron diffraction (LEED) as well as ultraviolet and X-ray photoelectron spectroscopy (UPS and XPS). XSW revealed that the adsorption distances of F4PEN in (sub)monolayers on Ag(111) were 3.00 Å for carbon atoms and 3.05 Å for fluorine atoms. The F4PEN monolayer was essentially lying on Ag(111), and multilayers adopted π-stacking. Our study shed light not only on the F4PEN–Ag(111) interface but also on the fundamental adsorption behavior of fluorinated pentacene derivatives on metals in the context of interface energetics and growth mode.

Highlights

The performance of organicelectronic devices is strongly affected by the energy level alignment at the various interfaces in such devices [1,2,3]
The determination of the vertical adsorption heights of F4PEN inmonolayers on Ag(111) relied on high-resolution core level spectra, which are shown in Figure 1
Following the assignment of the F4PEN core levels on Cu(111) [63], the C 1s peak centered at 287.29 eV binding energy (BE) was assigned to the carbon atoms bound to the fluorine atoms (C–F), and the main peak centered at 284.88 eV BE was assigned to the carbon atoms in the backbone of F4PEN (C–C)

Summary

Introduction

The performance of organic (opto)electronic devices is strongly affected by the energy level alignment at the various interfaces in such devices [1,2,3]. Is believed to decrease the coupling strength between the substrate and the adsorbate [9,10,11]. At such interfaces, vertical adsorption heights [12,13], interface dipoles (vacuum level shifts) [9,14] and the energy level alignment [15,16,17] are affected by fluorination. Overall, predicting the impact of fluorination on the energetics at organic–metal interfaces still remains a challenge

Results

Discussion

Conclusion