Monolithic Electrically-Driven Retroreflector Based on Gold Nanoparticles Embedded in Ferroelectric Polymer

The surface plasmon resonance (SPR) observed in metal nanostructures finds application in biosensing, optical communication technologies, and neuromorphic computing. There it enables the detection and transduction of dielectric environment changes in the vicinity of the metal nanostructure. Combining this principle with materials where the dielectric environment can be electrically modulated, it becomes possible to realize active optoelectronic plasmonic devices specifically designed for optical communication technologies. In this work, the use of an organic ferroelectric polymer to reversibly modulate the localized SPR (LSPR) of gold nanoparticles (AuNPs) inducing a reversible spectral shift of the resonance is investigated. The proposed plasmonic modulator is based on a two-terminal device composed of AuNPs deposited on a transparent conductive electrode, covered by a ferroelectric polymer poly(vinylidene fluoride-co-trifluoroethylene) with a metallic electrode on top also serving as the mirror. By applying a voltage bias between the two electrodes, an electric field is generated within the device, enabling precise control over the dielectric environment of the AuNPs and thereby modulating the LSPR. It is demonstrated that this concept can be easily fabricated, potentially flexible, lightweight, and robust, making it an attractive choice for optical communication devices, particularly as a free space modulating retroreflector. This study explores using a ferroelectric polymer to modulate the surface plasmon resonance (SPR) of gold nanoparticles (AuNPs) in an optoelectronic device. Applying voltage between electrodes alters the dielectric environment, causing a reversible shift in SPR, crucial for optical communication devices like modulating retroreflectors. The design is simple, potentially flexible, lightweight, and robust, making it suitable for practical applications.image (c) 2024 WILEY-VCH GmbH