Tailored Surfaces/Assemblies for Molecular Plasmonics and Plasmonic Molecular Electronics

Abstract

Molecular plasmonics uses and explores molecule-plasmon interactions on metal nanostructures for spectroscopic, nanophotonic, and nanoelectronic devices. This review focuses on tailored surfaces/assemblies for molecular plasmonics and describes active molecular plasmonic devices in which functional molecules and polymers change their structural, electrical, and/or optical properties in response to external stimuli and that can dynamically tune the plasmonic properties. We also explore an emerging research field combining molecular plasmonics and molecular electronics.

From active plasmonic devices to plasmonic molecular electronics

“…By controlling the characteristics of the molecule, it is possible to modify (i) the apparent dielectric function of the environment of the NP; (ii) the electromagnetic coupling between the plasmon and the molecule; or (iii) that between two adjacent NPs which tune the LSPR frequency. In this work we focus on electrochemical input but electrical, optical, mechanical, thermal and chemical inputs can also be used and have been reviewed elsewhere …”

“…In this work we focus on electrochemical input but electrical, optical, mechanical, thermal and chemical inputs can also be used and have been reviewed elsewhere. [15][16][17] The first active molecular plasmonic devices were developed using electrochemistry on plasmonic electrodes and were derived from molecular actuators. 18 Deposition of an electroactive thin film on the NPs makes it possible to modulate the LSPR by means of the potential applied to the electrode, using the oxido-reduction properties of the deposited layer.…”

Determining the Molecular Dipole Orientation on Nanoplasmonic Structures

“…The ability to understand the effects of the molecular dipole orientation of a monolayer on its coupling to plasmonic structures remains a challenge for molecular plasmonics. The dipole orientation of molecular coatings has been shown to affect not only the molecular vibrational, − optical, − chiroptical, , bioactivity, − and electron transport properties but also the plasmon resonance of the nanoparticles. ,, Control of the changes in molecular and plasmonic properties is vital for the use of plasmonic particles in solar cell ,− and sensing applications. ,− Of particular interest is the coupling between plasmons and J-aggregate films. − Recent experimental and theoretical studies have shown that in a strong-coupling regime, hybrid molecular-plasmonic modes appear with highly controllable resonances. − Even outside the strong-coupling regime, physically relevant processes such as enhanced absorption and exciton induced transparency occur at weaker coupling strengths. , Modification of molecular properties such as width, oscillator strength, or orientation has been shown to be a potentially attractive way of obtaining the desired optical properties in model systems. , Developing a methodology to extend these studies to an arbitrary system would provide useful physical insights.…”

“…The ability to understand the effects of the molecular dipole orientation of a monolayer on its coupling to plasmonic structures remains a challenge for molecular plasmonics. The dipole orientation of molecular coatings has been shown to affect not only the molecular vibrational, 1−3 optical, 4−9 chiroptical, 10,11 bioactivity, 12−15 and electron transport properties 6 but also the plasmon resonance of the nanoparticles. 7,16,17 Control of the changes in molecular and plasmonic properties is vital for the use of plasmonic particles in solar cell 8,17−19 and sensing applications.…”

Optical probes of molecules as nano-mechanical switches

“…Combining many thousands of such pull-off conductance measurements delivers systematic results which depend on the molecular electronic states. Alternative in situ averaging over many molecules through large-area contacts can also access molecular electronic properties [10][11][12] , with damage minimised by using nano-particulate or liquid metal contacts [13][14][15] (Fig. 1c).…”