Quantum interference enhances rectification behavior of molecular devices.

Area of Science:

• Molecular electronics
• Organic electronics
• Quantum chemistry

Background:

• Molecular rectifiers are crucial for nanoscale electronic devices.
• Designing molecules with efficient rectification properties remains a challenge.
• Understanding the relationship between molecular structure and electronic transport is key.

Purpose of the Study:

• To investigate the potential of cross-conjugated molecules as efficient molecular rectifiers.
• To explore the role of electron-donating and electron-withdrawing groups in molecular rectification.
• To elucidate the underlying mechanisms responsible for high rectification ratios.

Main Methods:

• Theoretical and computational modeling of molecular transport.
• Utilizing Non-Equilibrium Green's Function (NEGF) and Density Functional Theory (DFT).
• Analyzing transmission functions and molecular orbital localization.

Main Results:

• Cross-conjugated molecules with electron-donating groups exhibit high rectification ratios (up to 10x at 0.3 V).
• Donor-bridge-acceptor triads with electron-withdrawing groups achieve rectification ratios of approximately 100.
• High rectification is attributed to the localization of the Highest Occupied Molecular Orbital (HOMO).
• Quantum interference effects significantly enhance rectification when HOMO is localized.

Conclusions:

• Cross-conjugated molecular architectures are promising for developing efficient molecular rectifiers.
• HOMO localization and quantum interference are critical factors for high rectification performance.
• Molecular rectification can be tuned via electrochemical gating by manipulating anti-resonance peak positions.