Bipolar single-molecule electroluminescence and electrofluorochromism
arXiv:2210.11118 · doi:10.1103/PhysRevResearch.5.033027
Abstract
Understanding the fundamental mechanisms of optoelectronic excitation and relaxation pathways on the single-molecule level has only recently been started by combining scanning tunneling microscopy (STM) and spectroscopy (STS) with STM-induced luminescence (STML). In this paper, we investigate cationic and anionic fluorescence of individual zinc phthalocyanine (ZnPc) molecules adsorbed on ultrathin NaCl films on Ag(111) by using STML. They depend on the tip-sample bias polarity and appear at threshold voltages that are correlated with the onset energies of particular molecular orbitals, as identified by STS. We also find that the fluorescence is caused by a single electron tunneling process. Comparing with results from density functional theory calculations, we propose an alternative many-body picture to describe the charging and electroluminescence mechanism. Our study provides aspects toward well-defined voltage selectivity of bipolar electrofluorochromism, as well as fundamental insights regarding the role of transiently charged states of emitter molecules within OLED devices.
arXiv commentAccepted version of the manuscript. Published open access
References in corpus (10)
- Electrofluorochromism at the single molecule level
- Orbital-selective single molecule excitation and spectroscopy based on plasmon-exciton coupling
- Electrically-driven vibronic spectroscopy with sub-molecular resolution
- Energy funnelling within multichromophore architectures monitored with subnanometre resolution
- Fano description of single-hydrocarbon fluorescence excited by a scanning tunneling microscope
- Charge carrier injection electroluminescence with CO functionalized tips on single molecular emitters
- Exciton-trion dynamics of a single molecule in a radio-frequency cavity
- Many-body description of STM-induced fluorescence of charged molecules
- Real space visualization of entangled excitonic states in charged molecular assemblies
- Plasmon-driven motion of an individual molecule