Fabrication of PEDOT Nanocone Arrays with Electrochemically Modulated Broadband Antireflective Properties

Abstract

Ordered nanocone arrays of the electroactive polymer poly(3,4-ethylenedioxythiophene) (PEDOT) were fabricated by the simultaneous oxygen plasma etching of an electrodeposited PEDOT thin film coated with a hexagonally closed packed polystyrene bead monolayer. PEDOT nanocone arrays with an intercone spacing of 200 nm and an average nanocone height of 350 nm exhibited a low broadband reflectivity of <1.5% from 550 to 800 nm. Electrochemical modulation of the oxidation state of the PEDOT nanocone array film was used to change both its ex situ absorption spectrum (electrochromism) and reflection spectrum (electroreflectivity). The sign of the PEDOT nanocone array electroreflectivity was opposite to that observed from unmodified PEDOT thin films; this significant difference is attributed to the unique optical behavior of nanostructured surfaces with an interfacial layer that contains a graded mix of air and highly absorptive nanocones. The combined electrochromic and electroreflective behavior of the antireflective PEDOT nanocone array films should find promising applications in solar energy cells, sensors and other optical devices.

Bioinspired Microstructured Materials for Optical and Thermal Regulation

“…Also, the reflectance of the PEDOT with ARS was lower than that of the flat PEDOT film under different applied voltages. [ 63 ] This is of great significance for regulating the change in the transmittance. In order to reduce the cost of preparation, Zhao et al fabricated TiO 2 nanoarrays with an ARS on the surface and hydrothermally synthesized Prussian blue (PB) on the ARS of the TiO 2 .…”

“…Compared to flat PB films, the PB with ARS exhibited a reduced reflectance from 8% to 1% and an increased transmittance from 70% to 78%. [ 63,64 ]…”

Emission Enhancement of Fluorescent Molecules by Antireflective Arrays

“…However, the enhancement requires that the maximum excitation or emission of fluorescence molecule should match with the photonic crystal reflection, which restricts these techniques from practical applications [28–30]. The antireflective arrays can enhance the absorption of light in a wide range of wavelengths due to reducing the surface reflective [31–36]. In addition, the antireflective arrays can enhance the solid angle of the escape cone of fluorescent film.…”

Quantitative Characterization of Optical Coupling in Nanoporous ZnO–WO3 and ZnO–PEDOT Composite Electrodeposited Gratings Using Electrodiffraction Measurements

“…A PEDOT film was formed by the electrodeposition of 3,4-ethylene­dioxythiophene (EDOT) using a slightly modified procedure of a previously reported method. − To generate stable, uniform PEDOT films, it was necessary to first spin-coat a thin layer of PEDOT:PSS solution onto the FTO glass substrate to enhance conductivity and improve wetting of the surface, followed by the electropolymerization of EDOT to form a thicker layer of PEDOT. For the electrodeposition, an aqueous plating solution consisting of 0.02 M EDOT, 0.1 M SDS, and 0.1 M LiClO 4 was employed.…”