An electron acceptor molecule in a nanomesh: F4TCNQ on h-BN/Rh(111)

SURFACE SCIENCE

卷:678

Article

Cun, Huanyao^1,2  Seitsonen, Ari Paavo^3,4  Roth, Silvan^1,5  Decurtins, Silvio⁶  Liu, Shi-Xia⁶  Osterwalder, Jurg¹  Greber, Thomas¹ 

[1] Univ Zurich, Phys Inst, Winterthurerstr 190, CH-8057 Zurich, Switzerland

[2] Ecole Polytech Fed Lausanne, Inst Bioengn, Route Cantonale, CH-1015 Lausanne, Switzerland

[3] Ecole Normale Super, Dept Chim, 24 Rue Lhomond, F-75005 Paris, France

[4] Univ Zurich, Inst Chem, Winterthurerstr 190, CH-8057 Zurich, Switzerland

[5] Ecole Polytech Fed Lausanne, Inst Phys, Route Cantonale, CH-1015 Lausanne, Switzerland

[6] Univ Bern, Dept Chem & Biochem, Hochschulstr 6, CH-3012 Bern, Switzerland

关键词: Electron acceptor;    Charge transfer;    Work function;    h-BN;    STM;   

DOI  :  10.1016/j.susc.2018.04.026

来源: Elsevier

【 摘 要 】

The adsorption of molecules on surfaces affects the surface dipole and thus changes in the work function may be expected. The effect in change of work function is particularly strong if charge between substrate and adsorbate is involved. Here we report the deposition of a strong electron acceptor molecule, tetrafluorotetracyanoquinodimethane C12R4N4 (F(4)TCNQ) on a monolayer of hexagonal boron nitride nanomesh (h-BN on Rh(111)). The work function of the F(4)TCNQ/h-BN/Rh system increases upon increasing molecular coverage. The magnitude of the effect indicates electron transfer from the substrate to the F(4)TCNQ molecules. Density functional theory calculations confirm the work function shift and predict doubly-charged F(4)TCNQ(2-) in the nanomesh pores, where the h-BN is closest to the Rh substrate, and to have the largest binding energy there. The preferred adsorption in the pores is conjectured from a series of ultraviolet photoelectron spectroscopy data, where the a bands in the pores are first attenuated. Scanning tunneling microscopy measurements indicate that F(4)TCNQ molecules on the nanomesh are mobile at room temperature, as hopping between neighboring pores is observed.

【 授权许可】

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