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Updated: Oct 12, 2025
11:33
All-electronic Nanosecond-resolved Scanning Tunneling Microscopy: Facilitating the Investigation of Single Dopant Charge Dynamics
Published on: January 19, 2018
9.9K
Substituent-mediated quantum interference toward a giant single-molecule conductance variation.
Yi-Fan Zhou1, Wen-Yan Chang2, Jing-Zhe Chen3
1Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Institute of Physical Chemistry, Zhejiang Normal University, Jinhua 321004, People's Republic of China.
Nanotechnology
|November 19, 2021
Summary
Chemical substituents effectively tune quantum interference (QI) in single molecular junctions. This research demonstrates controlling QI through methoxy and nitryl groups, enabling high-performance molecular electronic devices.
Area of Science:
- Quantum chemistry
- Molecular electronics
- Nanoscience
Background:
- Quantum interference (QI) is crucial for nanoelectronic devices.
- Controlling QI in single molecular junctions remains a significant challenge.
Purpose of the Study:
- To investigate the effects of electron-donating (methoxy) and electron-withdrawing (nitryl) substituents on QI in meta-linked benzene molecular junctions.
- To explore chemical strategies for modulating QI for molecular device applications.
Main Methods:
- Computational modeling of transmission coefficients (T(E)).
- Experimental conductance measurements using scanning tunneling microscopy break junction (STM-BJ).
Main Results:
- Methoxy and nitryl groups at position 2 remove destructive quantum interference (DQI)-induced transmission dips.
- -OMe raises antiresonance energy at position 4; -NO2 removes DQI features.
- Substituents at position 5 show minimal impact on QI.
- Experimental results align with theoretical predictions.
- Achieved >2 orders of magnitude single-molecule conductance on/off ratio with -NO2 groups at room temperature.
Conclusions:
- Chemical substituents provide a viable method for tuning QI in single molecular junctions.
- Demonstrated control over QI opens pathways for high-performance molecular electronic devices.
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