Light Emission and Conductance Fluctuations in Electrically Driven and Plasmonically Enhanced Molecular Junctions

Area of Science:

• Nanoscience and Nanotechnology
• Plasmonics
• Molecular Electronics

Background:

• Molecular junctions integrate optical and electrical functionalities for nanoscale devices.
• Plasmonically enhanced junctions offer high field confinement and radiative efficiency.
• Understanding metal-molecule contacts is key for optoelectronic device development.

Purpose of the Study:

• Investigate correlated fluctuations in conductance and light emission in self-assembled molecular junctions.
• Explore the role of atomic-scale fluctuations in the optoelectronic response.
• Assess the stability and long-term functionality of these nanoscale devices.

Main Methods:

• Fabrication of self-assembled metal-molecule-metal junctions with nanoparticle bridges.
• Simultaneous measurement of electrical conductance and tunneling-induced light emission at room temperature.
• Analysis of fluctuations and their correlation with plasmonic modes.

Main Results:

• Electrical conductance and light emission exhibit high sensitivity to atomic-scale fluctuations.
• Fluctuations are linked to discrete steps in conductance and varying emission intensities.
• These phenomena suggest the dominance of localized, point-like sources in the optoelectronic response.
• Devices demonstrate long-term stability at room temperature and under electrical bias.

Conclusions:

• Atomic-scale fluctuations significantly impact the optoelectronic behavior of molecular junctions.
• The findings provide insights into the fundamental mechanisms governing metal-molecule contacts.
• These stable, functional molecular junctions hold promise for advanced nanoscale optoelectronic applications.