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Determination of the Photoisomerization Quantum Yield of a Hydrazone Photoswitch
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Electroisomerization blinking of an azobenzene derivative molecule
Sylvie Godey1, Hugo Therssen1, David Guérin1
1University Lille, CNRS, University Polytechnique Hauts-de-France, UMR 8520-IEMN-Institut d'Electronique de Microélectronique et de Nanotechnologie, F-59000 Lille, France.
Nanotechnology
|December 24, 2024
Summary
We observed reversible switching in azobenzene molecules using scanning tunneling microscopy (STM). This molecular switching, triggered by STM bias, creates a blinking effect, demonstrating bistability at low temperatures.
Area of Science:
- Molecular electronics
- Surface science
- Photochemistry
Background:
- Azobenzene derivatives exhibit photoisomerization between cis and trans states.
- Scanning tunneling microscopy (STM) allows atomic-scale surface imaging and manipulation.
- Controlling molecular states with electrical bias is crucial for molecular devices.
Purpose of the Study:
- To investigate the reversible switching of an azobenzene derivative induced by STM bias.
- To demonstrate bistability in molecular switching behavior.
- To explore the potential of electrical control over molecular isomerization.
Main Methods:
- Utilized scanning tunneling microscopy (STM) under ultra-high vacuum and low-temperature conditions.
- Applied electrical bias (+2 V and -2 V) using the STM tip to induce molecular switching.
- Observed and recorded the cis-to-trans and trans-to-cis isomerization events during STM imaging.
Main Results:
- Demonstrated reversible cis-trans and trans-cis switching of the azobenzene derivative.
- Observed sub-second switching times, leading to a visible 'blinking' effect in STM images.
- Confirmed that the switching is induced by the electric field generated by the STM bias.
Conclusions:
- The azobenzene derivative exhibits reversible and bistable switching behavior controlled by STM electrical bias.
- This electrical switching mechanism opens possibilities for nanoscale molecular switches and memory devices.
- The observed blinking effect highlights the dynamic control achievable at the molecular level.
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