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Reversible Broad-Bias Photoswitching of DNA Molecular Junctions via Azobenzene-Induced π‑Stack Disruption
Yunxia Feng1,2, Kai Qu1, Ruiqi Yang1
1Department of Materials Science and Engineering, MATEC, Guangdong Technion-Israel Institute of Technology, Shantou, Guangdong 515063, China.
JACS Au
|May 1, 2026
Summary
Researchers developed DNA photoswitches using azobenzene. These switches reversibly control electrical conductivity in DNA by modulating π-conjugation, offering stable and efficient molecular switching for electronic applications.
Area of Science:
- Molecular Electronics
- Supramolecular Chemistry
- DNA Nanotechnology
Background:
- Developing molecular photoswitches for DNA electronics is challenging.
- Previous attempts to integrate photoswitches into DNA have faced limitations.
Purpose of the Study:
- To create reversible photoswitches operating within the DNA π-stack.
- To investigate the effect of azobenzene incorporation on DNA conductance.
Main Methods:
- Incorporation of azobenzene moieties into DNA duplexes with baseless opposite sites.
- Conductive-probe atomic force microscopy (CP-AFM) for electrical measurements.
- Ultraviolet photoelectron spectroscopy (UPS) for electronic structure analysis.
Main Results:
- Reversible trans-cis photoisomerization of azobenzene modulates DNA π-conjugation and conductance.
- The cis isomer significantly disrupts π-overlap, reducing current by up to 2 orders of magnitude.
- High on/off ratios (>50 at 1.5 V) and stability were achieved, increasing with azobenzene units.
Conclusions:
- Azobenzene photoswitches enable robust, reversible control of DNA conductivity.
- Switching is attributed to enhanced charge transfer suppression via backscattering and quantum interference.
- This work provides a stable molecular switch for DNA-based electronic devices.
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