Tunable Plasmochromic Devices Using Gold Nanoislands Integrated with an Electropolymerized Organic Semiconductor

Area of Science:

• Plasmonics
• Materials Science
• Nanotechnology

Background:

• Active plasmonics requires reversible control of local surface plasmon resonances (LSPR).
• Existing devices often use lithographically fabricated nanostructures and conductive polymers like polyaniline (PANI).
• There's a need for novel materials and scalable fabrication methods in active plasmonics.

Purpose of the Study:

• To introduce poly(3-methylthiophene) (P3MT) as a tunable dielectric medium for active plasmon control.
• To utilize thermally dewetted gold nanoislands (AuNIs) as scalable plasmonic nanostructures.
• To explore active plasmonic devices based on P3MT and AuNIs.

Main Methods:

• Fabrication of active plasmonic devices with AuNIs coated by ultrathin P3MT shells (12-15 nm).
• Testing of devices by modulating P3MT between reduced and oxidized states.
• Evaluation of plasmochromic performance, including modulation depth, response time, reversibility, chromaticity, and stability.

Main Results:

• Achieved a reversible average LSPR modulation of 22 nm using P3MT-coated AuNIs.
• Demonstrated performance comparable to or exceeding other electrochromic polymers at similar thicknesses.
• Observed stable plasmonic shifts after 1000 cycles of modulation.

Conclusions:

• P3MT is a viable and effective tunable dielectric medium for active plasmonics.
• Thermally dewetted AuNIs offer a scalable and cost-effective platform for active plasmonic devices.
• This work enables future developments in tunable organic photovoltaics, photodiodes, and field-effect transistors.