Results 1 - 10 of 571
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[en] Highlights: • Pyridinium-salt-based electrochromic materials, TPCBDs, were designed and synthesized. • TPCBDs exhibit dual-colored and fast electrochromic switching properties. • N-substituents significantly influence their electrochromic properties. - Abstract: This work reports novel dual-colored and fast switching electrochromic materials based on pyridinium salts, 1,1′,1″,1‴-tetrakis(4,4′,4″,4‴-tetrapyridyl)cyclobutane derivatives (TPCBDs). TPCBDs show outstanding electrochromic properties including fast electrochromic switching, dual color, reasonable contrast, low driving voltage, and good stability. TPCBDs are promising candidates for visible electrochromic displays because of their remarkable electrochromic behaviors.
[en] New optical writing and electrical erasing devices have been successfully fabricated that exploit the photochromism and electrochromism of viologen. In a preliminary study, both the structures of viologen and device were investigated in detail by UV–vis spectra in order to confirm their effects on the optical writing and electrical erasing performances of corresponding devices. For sandwiched, single and complementary devices based on benzyl viologen (BV 2+), only optical writing can be performed, not electrical erasing operations, which indicated these devices cannot realize optical information rewriting. For single and complementary devices based on styrene-functional viologen (V BV 2+) and acrylic-functional viologen (ACV 2+), optical writing and electrical erasing operations can be reversibly performed and optical information rewriting realized. It is clear that single devices based on V BV2+ and ACV2+ possess better performance accompanied with contrast without significant degradation and bleaching times and without significant deterioration over 10 repeated writing/erasing cycles. Furthermore, we put forward possible mechanisms for sandwiched, single and complementary devices based on V BV2+ and ACV2+ for the optical writing and electrical erasing operations. This study provides a new strategy to design optical writing and electrical erasing devices to realize optical information rewriting. (paper)
[en] Highlights: • A polyoxometalate has been incorporated into a polymer. • An electrochromic behavior has been evidenced. • An hybrid organic/inorganic film has been prepared with PVK. • Electrochromism has been characterized by spectroelectrochemistry.
[en] Highlights: • Unearthed hybrid TENGs with robust design and simple structure. • Stable and waterproof. • Easy to integrate with electrochromic film and acts as a pressure sensitive device. Developing novel smart materials for the next generation of advanced electronic devices represents a major challenge as well as an exciting opportunity in the direction of integration, miniaturization, and flexibility. Here an unearthed single-electrode triboelectric nanogenerator (TENG) is fabricated from three-dimensionally hybridized copper/polydimethylsiloxane powering films. This robust design simplifies the traditional contact-separation mode so that the as-fabricated single-electrode TENG is simple, stable, waterproof and can be operated without grounding. The output current reaches 1.2 μA cm−2 when a pressure as small as 5 N cm−2 is applied, which leads to the invention of a pressure sensitive device by integrating with an electrochromic film. The pioneering unearthed single-electrode working modes start up a multifunctional platform for both energy harvesting and self-powered touch sensors.
[en] Highlights: • Hydrogel of PEDOT:PSS was prepared with PEO and LiClO4. • Electrochromic response of the mixed device was improved. • ηd increases up to 834 C−1 cm2 after 1.5 s of switch time. Two flexible electrochromic devices based on PEDOT:PSS were prepared by roll-to-roll method, these devices were built with the conventional layered geometry or using PEO:LiClO4 and charge balancing material mixed at the same layer. Analysis of the properties leads to the conclusion that the presence of the percolation channels of PEDOT:PSS inside the PEO/LiClO4 results in the performance improvement as monitored by impedance spectroscopy and the respective Randles equivalent circuits. From mixed electrochromic layer, ηd increases up to 834 C−1 cm2 after 1.5 s of switch time, while the corresponding layered device showed ηd of 472 C−1 cm2 at the same time interval.
[en] In this research, the effect of Fe2O3 content on the electrochromic properties of WO3 in thermally evaporated (WO3)1-x-(Fe2O3) x thin films (0 ≤ x ≤ 0.4) has been studied. The atomic composition of the deposited metal oxides was determined by X-ray photoelectron spectroscopy analysis. The surface morphology of the thin films has been examined by atomic force microscopy. The surface roughness of all the films was measured about 1.3 nm with an average lateral grain size of 30 nm showing a smooth and nanostructured surface. The electrochromic properties of (WO3)1-x-(Fe2O3) x thin films deposited on ITO/glass substrate were studied in a LiClO4 + PC electrolyte by using ultraviolet-visible spectrophotometry. It was shown that increasing the Fe2O3 content leads to reduction of the optical density (ΔOD) of the colored films and also leads to increasing the optimum coloring voltage from 4 to 6 V in which ΔOD shows its maximum values, in our experimental conditions. Furthermore, by using this procedure, it is possible to make an electrochromical filter which behaves similar to the colored WO3 film in the visible region, while it can be nearly transparent for near-infrared wavelengths, in contrast of the pure colored WO3 film
[en] This paper reports an on-chip electrochromic micro display made of polyaniline (PANi) which can be easily made on a CMOS chip. Micro-patterned PANi thin films were selectively deposited on pre-patterned microelectrodes by using electrodeposition. The optimum conditions for deposition and electrochromism were investigated. An 8-pixel on-chip micro display was made on a Si chip. The color of each PANi film could be independently but simultaneously controlled, which means any 1-byte digital data could be displayed on the display. The PANi display had a response time as fast as about 100 ms, which means the transfer data rate was as fast as 80 bits per second. (paper)
[en] 4,4'-Di(N-carbazoyl)biphenyl monomer (CBP) was synthesized and coated onto ITO-glass surface by electrochemical oxidative polymerization. Its CV shows two distinct one-electron and stepwise oxidation processes occurred at 1.29 and 1.61 V. By using this property, the monomer was electrochemically polymerized separately at these oxidation states and thus, two different oligomer films were obtained afterwards. Their spectro-electrochemical and electrochromic properties were also investigated. Switching ability of the oligomers was evaluated by kinetic studies upon measuring the percent transmittance (%T) at their maximum contrast point, indicating that these oligomers were found to be suitable material for electrochromic devices.
[en] In nature, some animals change their deceptive coloration for camouflage, temperature preservation or communication. This astonishing function has inspired scientists to replicate the color changing abilities of animals with artificial skin. Recently, some studies have focused on the smart materials and devices with reversible color changing or light-emitting properties for instantaneous strain visualization. However, most of these works only show eye-detectable appearance change when subjected to large mechanical deformation (100%–500% strain), and conspicuous color change at small strain remains rarely explored. In the present study, we developed a user-interactive electronic skin with human-readable optical output by assembling a highly sensitive resistive strain sensor with a stretchable organic electrochromic device (ECD) together. We explored the substrate effect on the electromechanical behavior of graphene and designed a strategy of modulus-gradient structure to employ graphene as both the highly sensitive strain sensing element and the insensitive stretchable electrode of the ECD layer. Subtle strain (0–10%) was enough to evoke an obvious color change, and the RGB value of the color quantified the magnitude of the applied strain. Such high sensitivity to smaller strains (0–10%) with color changing capability will potentially enhance the function of wearable devices, robots and prosthetics in the future. (paper)