Stability Of Electrochromic Devices Research Articles

A dual functional Co3O4 thin film with remarkable electrochromic and energy storage performance in the electrolytes of choline chloride and urea

The electrolyte layer plays an important role in ion transport in electrochromic devices, and the optimized preparation of efficient electrolytes can positively affect the conduction process on the electrode surface and at the electrode-electrolyte interface.In this study, we start from a green perspective while improving the performance. Combined with typical eutectic solvents: choline chloride and urea materials. A suitable ratio favorable for the reaction of Co3O4 film is explored and combined with sodium hydroxide, a traditional electrolyte, to enhance the electrochromic performance.The electrochromic and electrochemical properties of Co3O4 films prepared via the sol-gel method in the novel electrolyte were then evaluated. The results show that the performance has been greatly improved, the transmittance rate is 2.5 times higher than the original, the coloration efficiency is 5.8 times higher than the original, and it is more stable and has higher charging and discharging efficiency. This presents a promising avenue for the advancement of oxide films as bifunctional materials for electrochromism and energy storage. The newly developed electrolyte may prove beneficial in enhancing the performance and stability of electrochromic devices through the use of alkaline electrolytes.

In Situ Raman Observation of Zinc-Induced Structural Dynamics and Charge Transfer of a Layered V2O5

In situ techniques to disclose electrochemical and interfacial behavior between electrode and electrolyte in a quantitative manner are in high demand in numerous fields including electrochromism, energy storage as well as basic science research. This work demonstrates a self-made in situ Raman spectra technique coordinating with an electrochemical workstation and its utility for zinc-induced structural dynamics and charge transfer of a layered V2O5. The increase or decrease of Raman activity modes of V–O3, O1–V–O2 and O1–V–O3 at applied low or high voltages is probably due to the presence of “free pathway” within layers. An interpretation is proposed where the two stages of bidirectional reversibility of Zn2+ intercalation and deintercalation from “free pathway” and V2O5 matrix occur via an electrochemical process, followed by Zn2+ continuous aggregation, fusion and possible transformation to ZnxV2O5. A distinct difference between Li+-based and Zn2+-based electrolytes is that the Raman active modes between V atom and apical oxygen are almost not enhanced or weakened for V2O5 in Zn2+-based electrolyte, most likely due to the greater Coulomb force of Zn2+ on V2O5 matrix than that of Li+. These observations have implications for understanding the performance and stability of electrochromic devices.

Evaluation of Electrochromic Device Influenced by Various Formulation of Solid Polymer Electrolyte

Electrochromic devices (ECDs) using various polymer electrolyte membranes were evaluated in relation to their optical and electrochemical properties. It was found that the composition of polymer matrix markedly influence the transmittance change (ΔT) and stability of ECDs. The electrochromic (WO3) and ion storage (Antimony tin oxide; ATO) layers were fabricated using dry deposition method. Moreover, various types of polymer matrix were used as the electrolyte, i.e., Liquid; PVdF-HFP (UV-0); PEGDMA-PEGMA/PVdF-HFP blended (UV-30); and PEGDMA-PEGMA solid (UV-100) membranes. ECDs using UV-30 exhibited good cyclability, in which the ΔT of 35% was maintained over 200 cycles. Furthermore, as a result of electrochemical analysis, ECD using UV-30 showed charge density of 34.43 mC/cm2 with low charge transfer resistance of 237.7 Ω at the interface between the coloration layer and electrolyte. Therefore, the solid polymer matrix electrolyte (UV-30) improved the electrochromic performance including stability due to excellent ion dissociation and ion mobility in the electrolyte.

Stability of Polymer‐based Electrochromic Devices

In this paper, the influence of some external conditions (such as temperature and light intensity) on the stability of electrochromic devices is studied, and the calculation method of device transparency Y is given. By building a test platform and simulating the external conditions, the relationship between transparency Y and time in different initial states of the device is drawn. Finally, with the increasing of temperature and light intensity, the decay speed of the device is accelerated.

A comprehensive study on utilization of N-substituted poly(2,5-dithienylpyrrole) derivatives in electrochromic devices

In this study, we disclose the utilization of the conducting homopolymer and copolymers based on 4-(2,5-di-thiophen-2-yl-pyrrol-1-yl)–N-(ferrocenyl methyl)-phenylamine (SNS-An-Fc) and 1-(2-ethyl-hexyl)-2,5-di-thiophen-2-yl-2,3-dihydro-1H-pyrrole (SNS-HE) in electrochromic devices (ECDs). For this purpose, four different dual type, complementary colored devices were assembled in glass/ITO/poly(SNS-R)/PEDOT/ITO/glass configuration. Electrochromic properties of all devices were investigated by spectroelectrochemistry, switching, coloration efficiency, open circuit, stability studies and colorimetry measurements. When compared with the alkyl functionalized analog, tethering of ferrocene group on to polymer chain was found out to be an effective strategy to enhance coloration efficiency. Generally, the switching speeds and stability of ECDs having copolymers as their active layer were found to better than the devices of corresponding homopolymers. On the other hand devices assembled with homopolymers exhibited superior optical memory. Our studies indicate that all the ECDs have good redox stability, esthetically pleasing colors and they could be operated between 0.0V and 1.2V.