Electronic structure evolution at DBBA/Au(111) interface W/O Bismuth insertion layer
| Autor: | Yunhao Lu, Junting Xiao, Yuan Zhao, Shitan Wang, Bingchen He, Fei Song, Han Huang, Yao Wang, Qiwei Tian, Haipeng Xie, Yongli Gao |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Materials science
Photoemission spectroscopy chemistry.chemical_element 02 engineering and technology Electronic structure 010402 general chemistry 01 natural sciences Molecular physics law.invention Bismuth symbols.namesake law Materials Chemistry Work function Thin film Mechanical Engineering Fermi level Metals and Alloys 021001 nanoscience & nanotechnology Condensed Matter Physics 0104 chemical sciences Electronic Optical and Magnetic Materials chemistry Mechanics of Materials symbols Scanning tunneling microscope 0210 nano-technology Graphene nanoribbons |
| Zdroj: | Synthetic Metals. 251:24-29 |
| ISSN: | 0379-6779 |
| Popis: | Atomically precise graphene nanoribbons (GNRs) can be on-surface synthesized from halogen containing molecular precursors. Here, we investigated the electronic structure evolution of 10,10′-dibromo-9,9′-bianthracene (DBBA), a famous precursor to 7-AGNRs, on both A u ( 111 ) and B i - 3 × 3 - A u ( 111 ) as a function of film thickness and post-annealing temperature using photoemission spectroscopy, low temperature scanning tunneling microscopy and density functional theories. No obvious changes in electronic structure of DBBA in three STM-observed configurations can be detected, indicating that nonplanar π -conjugated DBBA is physisorbed on both surfaces. The energy level alignments at the DBBA-substrate interfaces are demonstrated. Bismuth(Bi) insertion layer makes molecular−substrate interaction weaker, and makes the energy levels of DBBA thin film rigidly shift by ˜0.70 eV away from Fermi level, which enlarges the hole injection barrier and results in DBBA desorption at ˜470 K before dehalogenation occuring. The surface work function reduction can be explained by the push back effect and charge transfer induced interface dipole. Our findings explain why 7-GNRs could not be formed on B i - 3 × 3 - A u ( 111 ) . |
| Databáze: | OpenAIRE |
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