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Shape-persistent ladder molecules exhibit nanogap-independent conductance in single-molecule junctions
Xiaolin Liu1,2, Hao Yang1,3, Hassan Harb4
1Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, IL, USA.
Nature Chemistry
|August 26, 2024
Summary
Shape-persistent ladder molecules offer unprecedented control over single-molecule electronic devices. Their unique structure ensures consistent molecular conductance, overcoming challenges posed by dynamic nanoscale junctions.
Area of Science:
- Molecular electronics
- Nanoscale science
- Organic chemistry
Background:
- Precise control of current flow in single molecules is crucial for molecular electronic devices.
- Electron transport in single molecules is highly sensitive to dynamic conformational changes within nanoscale junctions.
Purpose of the Study:
- To develop a strategy for controlling molecular conductance that is independent of junction displacement.
- To investigate the use of shape-persistent molecules for stable electron transport.
Main Methods:
- Synthesis of chemically diverse, charged ladder molecules using a one-pot multicomponent ladderization strategy.
- Measurement of molecular conductance in nanoscale junctions using techniques sensitive to junction displacement.
- Comparison of conductance properties between ladder molecules and non-ladder analogues.
Main Results:
- Ladder molecules exhibited molecular conductance nearly independent of junction displacement (d[log(G/G0)]/dx ≈ -0.1 nm⁻¹).
- Non-ladder analogues showed significantly higher sensitivity to nanogap changes (d[log(G/G0)]/dx ≈ -7 nm⁻¹).
- Ladder molecules demonstrated a narrow distribution of conductance values during dynamic junction manipulation, attributed to their rigid backbone and restricted group rotation.
Conclusions:
- Shape-persistent ladder molecules provide a robust platform for achieving stable, gap-independent molecular conductance.
- The design principles are generalizable, as demonstrated with a butterfly-like molecule.
- This strategy opens new avenues for designing reliable molecular electronic components.
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