Probing the interplay between geometric and electronic structure in a two-dimensional K-TCNQ charge transfer network.
Faraday Discuss
; 204: 97-110, 2017 10 26.
Article
en En
| MEDLINE
| ID: mdl-28792036
ABSTRACT
Scanning tunnelling microscopy (STM), low energy electron diffraction (LEED), ultraviolet and soft X-ray photoelectron spectroscopy (UPS and SXPS) have been used to characterise the formation of a coadsorption phase of TCNQ and K on Ag(111), while the normal incident X-ray standing waves (NIXSW) technique has been used to obtain quantitative structural information. STM and LEED show that an ordered incommensurate phase is formed in which the K atoms are surrounded by four TCNQ molecules in a 'windmill' motif, characteristic of other metal/TCNQ phases, in which the nominal TCNQ K stoichiometry is 1 1. UPS and SXPS data indicate the TCNQ is in a negatively-charged state. NIXSW results show that the carbon core of the TCNQ is essentially planar at a height above the Ag(111) surface closely similar to that found without coadsorbed K. In the presence of TCNQ the height of the K ions above the surface is significantly larger than on clean Ag(111), and the ions occupy sites above 'holes' in the TCNQ network. NIXSW data also show that the N atoms in the molecules must occupy sites with at least two different heights above the surface, which can be reconciled by a tilt or twist of the TCNQ molecules, broadly similar to the geometry that occurs in bulk TCNQ/K crystals.
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Colección:
01-internacional
Banco de datos:
MEDLINE
Idioma:
En
Revista:
Faraday Discuss
Asunto de la revista:
QUIMICA
Año:
2017
Tipo del documento:
Article
País de afiliación:
Reino Unido