Uncovering the (un-)occupied electronic structure of a buried hybrid interface
| Autor: | Jana Hildebrandt, Niklas Mutz, Jan-Christoph Deinert, Sesha Vempati, Lea Bogner, Stefan Hecht, Lukas Gierster, Anton Zykov, Julia Stähler, Stefan Kowarik, Clemens Richter, S. Blumstengel, Yves Garmshausen |
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| Rok vydání: | 2018 |
| Předmět: |
Materials science
Population FOS: Physical sciences 02 engineering and technology Electronic structure 01 natural sciences symbols.namesake organic/inorganic interfaces 0103 physical sciences interfacial electronic structure 541 Physikalische Chemie General Materials Science Work function ddc:530 010306 general physics education HOMO/LUMO energy level alignment education.field_of_study Condensed Matter - Materials Science business.industry Fermi level Materials Science (cond-mat.mtrl-sci) 021001 nanoscience & nanotechnology Condensed Matter Physics 530 Physik Photoexcitation Semiconductor Chemical physics 2PPE symbols ZnO ddc:541 Vacuum level 0210 nano-technology business |
| Zdroj: | Journal of Physics: Condensed Matter |
| DOI: | 10.48550/arxiv.1811.00779 |
| Popis: | The energy level alignment at organic/inorganic (o/i) semiconductor interfaces is crucial for any light-emitting or -harvesting functionality. Essential is the access to both occupied and unoccupied electronic states directly at the interface, which is often deeply buried underneath thick organic films and challenging to characterize. We use several complementary experimental techniques to determine the electronic structure of p -quinquephenyl pyridine (5P-Py) adsorbed on ZnO(1 0 −1 0). The parent anchoring group, pyridine, significantly lowers the work function by up to 2.9 eV and causes an occupied in-gap state (IGS) directly below the Fermi level EF. Adsorption of upright-standing 5P-Py also leads to a strong work function reduction of up to 2.1 eV and to a similar IGS. The latter is then used as an initial state for the transient population of three normally unoccupied molecular levels through optical excitation and, due to its localization right at the o/i interface, provides interfacial sensitivity, even for thick 5P-Py films. We observe two final states above the vacuum level and one bound state at around 2 eV above EF, which we attribute to the 5P-Py LUMO. By the separate study of anchoring group and organic dye combined with the exploitation of the occupied IGS for selective interfacial photoexcitation, this work provides a new pathway for characterizing the electronic structure at buried o/i interfaces. Deutsche Forschungsgemeinschafthttps://doi.org/10.13039/501100001659 |
| Databáze: | OpenAIRE |
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