Direct Observations of Surface Plasmon Polaritons in Highly Conductive Organic Thin Film

Abstract

Plasmonic effect plays a significant role in many optoelectronic devices and enables various innovative applications. It has been widely studied in metallic materials, for example, Ag and Au, and later was expanded to transparent conductive oxides, etc. However, such plasmonic structures have limitations in many emerging optoelectronics including flexible optoelectronics, organic optoelectronics, and so on, due to their inorganic natures. In this manuscript, we discovered that the acid-modified highly conductive organic PEDOT:PSS film shows interesting plasmonic properties in the vis–NIR region and exhibits great potentials for activating surface plasmon polaritons. The dispersion curves of dielectric permittivity and optical constants of two modified PEDOT:PSS samples are obtained by inversion calculation of the spectroscopic ellipsometry data with the Drude–Lorentz dispersion model. The permittivity crossover wavelengths λC and the surface plasmon wavelengths λsp are found to be located squarely in the 650–900 nm range, which will enable future plasmonic device applications in the vis–NIR region. The activation of surface plasmon polaritons propagation mode of modified PEDOT:PSS is directly observed and confirmed by prism coupling experiments. In addition, further quantitative analysis revealed that our modified PEDOT:PSS samples have comparable abilities to generate, propagate, and confine surface plasmon polaritons as indium tin oxide (ITO). To the best of our knowledge, this is the first direct demonstration of an organic structure showing equivalent plasmonic properties to the inorganic ones. We believe it will open up much more possibilities for the optoelectronic devices, due to the flexibility, lightness, biological compatibility, and solution processability of the organic plasmonic materials.

Tunable Organic ENZ Materials with Large Optical Nonlinearity

“…The PEDOT film with near-visible ENZ wavelengths is treated by acid (Supporting Information Figure S2). We have utilized this preparation method to report a near-visible ENZ wavelength and the excitation of surface plasmonic polaritons in PEDOT films …”

“…We have utilized this preparation method to report a near-visible ENZ wavelength and the excitation of surface plasmonic polaritons in PEDOT films. 53 The Drude dispersion model reveals the relationship among ω ENZ , Im(ε(λ ENZ )), and the electrical properties obtained by the Hall measurement…”

“…The film was dried on a hot plate at 160 °C after about 5 min. More details about preparation are available in refs and .…”

Dynamic Conducting Polymer Plasmonics and Metasurfaces

“…These sensors could use the inherent sensitivity of plasmonic resonances to the surrounding environment to monitor biorecognition reactions, just as for traditional nanoplasmonic biosensors. − However, we envision additional functionalities beyond that of traditional plasmonic sensors, for example, based on property changes induced by the binding of biomolecules to functional groups in the polymers. Similarly, surface plasmon polaritons of conducting polymer films may also be used to develop new types of biosensors. Studies of thermoplasmonic effects, which have enabled various applications based on metallic plasmonic systems, − form yet another unexplored direction for conducting polymer plasmonic systems.…”

Polarization Selectivity of the Thin-Metal-Film Plasmon-Assisted Fiber-Optic Polarizer

“…Many optical systems have operational characteristics that are highly dependent on the polarization of the light, including biosensors, interferometric sensors, nanowire lasers, coherent optical communications, quantum communications, etc. − Many types of polarizers with different structures or different polarization mechanisms, such as birefringence, reflection, selective absorption, and scattering, have been reported. , Initially, attention has focused on bulk-optic polarizers . With the discovery and exploration of surface plasmon polaritons (SPPs) − and the development of accurate and dependable nanofabrication techniques, − fiber polarizers, including metallic plasmon-assisted fiber polarizers, − graphene-clad fiber polarizers, − and plasmonic photonic crystal fiber polarizers have blossomed. , …”