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Probing the interplay between geometric and electronic structure in a two-dimensional K–TCNQ charge transfer network
- Source :
- Faraday Discussions. 204:97-110
- Publication Year :
- 2017
- Publisher :
- Royal Society of Chemistry (RSC), 2017.
-
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.
- Subjects :
- Low-energy electron diffraction
Chemistry
02 engineering and technology
Electronic structure
021001 nanoscience & nanotechnology
01 natural sciences
Ion
Crystallography
X-ray photoelectron spectroscopy
Phase (matter)
0103 physical sciences
Molecule
QD
Physical and Theoretical Chemistry
010306 general physics
0210 nano-technology
Stoichiometry
Quantum tunnelling
Subjects
Details
- ISSN :
- 13645498, 13596640, and 03017249
- Volume :
- 204
- Database :
- OpenAIRE
- Journal :
- Faraday Discussions
- Accession number :
- edsair.doi.dedup.....c61c1cf81a2a8a87ea68ceee08500225
- Full Text :
- https://doi.org/10.1039/c7fd00093f