Three distinct conductance states in polycyclic aromatic hydrocarbon derivatives

Area of Science:

• Computational materials science
• Molecular electronics
• Organic electronics

Background:

• Polycyclic aromatic hydrocarbons (PAHs) are versatile organic molecules with potential applications in molecular electronics.
• Understanding the relationship between molecular structure and electrical properties is crucial for designing novel electronic devices.

Purpose of the Study:

• To investigate the electrical conductance of eight polycyclic aromatic hydrocarbons (PAHs).
• To determine how the number of aromatic rings (NAR) influences the electrical conductance of PAHs.
• To establish distinct conductance states and their correlation with electronic properties.

Main Methods:

• Utilized the tight-binding model (TBM) for electronic structure calculations.
• Employed density functional theory (DFT) to compute transmission curves and validate TBM results.
• Analyzed the energy gap (Eg) and its dependence on NAR.

Main Results:

• Identified three distinct electrical conductance states (low, medium, high) for the studied PAH derivatives.
• Correlated conductance states with transmission coefficients (T(E)) and energy gaps (Eg).
• Established a linear relationship between conductance and NAR (G ∝ NAR), with conductance increasing with NAR.

Conclusions:

• PAH conductance is tunable by controlling the number of aromatic rings.
• PAH molecules can function as conductors if their energy gap is less than 0.20 eV.
• The findings offer a significant advancement for the practical application of molecular electronics and device development.