Charge Tunneling along Short Oligoglycine Chains

Area of Science:

• Molecular electronics
• Surface chemistry
• Materials science

Background:

• Self-assembled monolayers (SAMs) are crucial for molecular electronics.
• Understanding charge transport (CT) mechanisms in SAMs is key to device development.
• Oligoglycines offer a unique molecular backbone for studying CT.

Purpose of the Study:

• To investigate charge transport through N-terminal cysteine-anchored oligoglycine SAMs.
• To compare the charge transport rates of oligoglycine SAMs with other molecular systems.
• To elucidate the mechanism governing charge transport in oligoglycine SAMs.

Main Methods:

• Fabrication of Au(TS)/SAM//Ga2O3/EGaIn junctions.
• Measurement of charge transport rates across oligoglycine SAMs.
• Comparison with structurally related SAMs.
• Density functional theory (DFT) calculations.

Main Results:

• Charge transport through oligoglycine SAMs is significantly faster than through n-alkanethiolates.
• Tunneling rates in oligoglycine SAMs are comparable to those in oligophenyl SAMs of similar length.
• DFT calculations support a superexchange mechanism involving amide bonds.

Conclusions:

• Oligoglycine SAMs facilitate rapid charge transport.
• The charge transport mechanism in oligoglycines involves superexchange facilitated by amide bond interactions.
• Oligoglycines represent a promising class of molecules for molecular electronic applications.