Molecular Orientation-Dependent Interfacial Energetics and Built-in Voltage Tuned by a Template Graphene Monolayer
| Autor: | Trisha L. Andrew, Robert J. Hamers, Lushuai Zhang, Susmit Singha Roy, Michael S. Arnold |
|---|---|
| Rok vydání: | 2014 |
| Předmět: |
Kelvin probe force microscope
Materials science Graphene Analytical chemistry Heterojunction Surfaces Coatings and Films Electronic Optical and Magnetic Materials law.invention Pentacene Crystal chemistry.chemical_compound General Energy chemistry law Chemical physics Work function Vacuum level Physical and Theoretical Chemistry Thin film |
| Zdroj: | The Journal of Physical Chemistry C. 119:45-54 |
| ISSN: | 1932-7455 1932-7447 |
| DOI: | 10.1021/jp508931e |
| Popis: | Highly transparent and conductive monolayer graphene was used as a template to tune the crystal orientation of pentacene from generic standing-up (001) to lying-down (022) in neat films. Spatially resolved Kelvin probe force microscopy (KPFM) was used to reveal the energy levels of pentacene thin films grown on substrates with and without the template graphene layer, as well as the energy level alignment in various pentacene-containing organic–organic heterojunctions. A correlation between crystal domain orientation and the work function was directly observed using KPFM. Up to 0.36 eV shifts in work function were observed in neat pentacene films over large areas (>0.5 in.2) upon orientation transition, likely due to the transition from Fermi level pinning (standing-up pentacene on ITO) to vacuum level alignment (lying-down pentacene on graphene–ITO). Morphology-induced energy level shifts versus interfacial electronic equilibration effects were disentangled using atomic force microscopy, KPFM, X-ray diffr... |
| Databáze: | OpenAIRE |
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