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Poly(vinylidene fluoride- normalco -hexafluoropropylene) (PVDF/HFP)-based membranes have been prepared using tri- o -cresyl phosphate, dibutyl phthalate, propylene carbonate, or triethyl phosphate as plasticizers. Scanning electron microscopy and the gas adsorption/desorption method were used to reveal the microporous structure of the membranes. Results indicate that the boiling point and viscosity of the plasticizers are important factors during the membrane-forming process. The membrane prepared with a plasticizer of higher boiling point can achieve higher porosity, electrolyte uptake, and thus higher ionic conductivity. The pore sizes of the PVDF/HFP membranes obtained in this study are mostly below 40 nm while the average pore sizes are smaller than 20 nm. The conductivities at room temperature are higher than 10−3Scm−1. The transference numbers measured using the dc polarization method coupled with ac impedance spectra are found to be above 0.7 when 1 M LiPF6 in ethylene carbonate/γ-butyrolactone (1:1 v/v) was used as the liquid electrolyte counterpart. © 2002 The Electrochemical Society. All rights reserved.

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Despite advances in numerous artificial synaptic devices, the search for a new functionalized synaptic device remains the subject of rigorous investigation for constructing neuromorphic systems. Optical readout functionality in artificial synapses is interesting as on-chip photonic integration technology could increase bandwidth and signal transmission, stop signal interference, reduce power loss, and provide degrees of freedom that complete the photonic neuromorphic system using light rather than electrons. Here, a waveguide-integrated electrochromic artificial synaptic device in which the electrolyte-gated electrical synaptic signal is read by optical means is demonstrated. The optically readable electrochromic synaptic device successfully imitates essential synaptic functions, such as short-and long-term plasticity, excitatory and inhibitory postsynaptic potentiation, and paired-pulse facilitation. In addition, randomly accessible nonvolatile multilevel optical memories are also demonstrated based on electrolyte ion dynamics that enable electrical switching of the transparency of the electrochromic material in a nonvolatile manner. This optically readable artificial synapse approach based on photonic integration circuit technologies provides insight into an exact reading of the emulation of the biological synapse in an optical manner and is a key step toward the implementation of non-conventional photonic neuromorphic systems with tunable bio-inspired synaptic functions.

Plasmonic air-gap disk resonators with 3.5 μm diameter and a 4 nm thick, 40 nm wide air gap for a mode area of only λ0(2)/15,000 were fabricated using photolithography only. The resonant modes were clearly identified using tapered fiber coupling method at the resonant wavelengths of 1280-1620 nm. We also demonstrate the advantage of the air-gap structure by using the resonators as label-free biosensors with a sensitivity of 1.6 THz/nm.

Electrochromic materials and devices have attracted much attention with their ability to tune the transmissions of visible to infrared (IR) light, allowing the creation of smart windows. This study presents a novel electrochromic device (ECD)‐based photonic device that can modulate IR light intensity in a planar optical waveguide ECD. To configure it, a multilayer ECD made of WO3 is integrated on a polymer optical waveguide platform. By using the waveguide to change the optical properties of the ECD electrically, IR light propagating along the optical waveguide core undergoes electroabsorption loss due to the change in charge carrier density in WO3 layer and its intensity is modulated with an extinction depth of 0.6 dB mm−1. Experimental results show that the device is capable of discrete intensity attenuation by applying a distinct level gate voltage. Periodic application of gate voltage leads the device to serve as an optical modulator on the order of subseconds. The results also confirm that a new approach to consider ECD‐based optical modulators can pave the way for the development of planar photonic‐integrated circuits and systems.

Electrochromic devices (ECDs) have been widely investigated for application in next-generation displays and smart windows owing to their highly efficient optical transmittance modulation properties.

light condition. Furthermore, low transmittance is another issue to be enhanced. To retain the stability of outdoor visibility, the intensity of illumination is necessarily increased, which lead to eye fatigue and increase power consumption. To ensure the properties of outdoor visibility and high energy efficiency, reflective-type display can be a solution technique. In particular, electrochromic devices based upon the reversible electrodeposition (RED) technology is suitable for transparent display. RED system realizes transparent and reflective mode as selectively formed and removed the reflector. [27-36] Although RED has potential to be used as the display applications, there are insufficient attempts on show colors. In typical display, pigment/dye-based and structural-based color filters have been studied to absorb or emit specific wavelengths. Despite pigment/dye-based color filter has wide viewing angle and high color ratio, it has low chemical stability and imperfect color impurity. [37-39] Whereas, structuralbased color filter such as plasmon resonance [40-43] and Fabry-Perot (FP) interferometer [44-51] on the basis of the interaction between nanostructure and incident light provides the merits of spectral selectivity, chemical and thermal stability. These advantages led to obtain multicolor in single RED device by controlling the silver structure for plasmonic resonance. [52-56] However, fine control the metal structure for multicolor is essential, which can affect limitation to reproducibility and stability. On the other hand, there is no case for multicolored RED device with FP interferometer. FP-type color filter generates only the selected light by using the thin-film interference effect of multiple reflected waves from reflector. Therefore, various colors can be tuned by variety of materials and controlled cavity with simple process. In terms of robustness to variation cavity, material that have low refractive index is proper to form the thin films. [46] Moreover, low absorption characteristic in visible range is required to reduce the optical loss. Compared to others, indium-tin-oxide (ITO) has relatively low refractive index and low absorption spectra in visible range. In this paper, we first proposed a new structure for a transparent/colored mirror switchable RED device by integrating the micropixelated ITO (red, green, and blue: RGB) cavities for the FP interferometer. A variable thickness of ITO films and partially reflective Tungsten (W) film were used as Reversible electrodeposition (RED) devices have been considered as the optical transmittance or reflectance switchable display for the reflective display applications. In this study, transparent/colored mirror switchable RED device is demonstrated by integrating the Fabry-Perot (FP) interferometer. Indium-tin-oxide (ITO)-based FP interference effect is utilized for color filter to emit particular wavelength. Color-switchable RED cells are researched using ITO (red, green, and blue (RGB)) films and tungsten (W) films as partially reflective la...