Feng Li,Mingyue Pan,Qi He,Qianhua Zhou,Qian Tang,Chengbin Gong
Multifunctional electrochromic materials are widely used in optoelectronic devices . Pyrene is a π-electron-rich group with fluorescence properties. Ester-functionalized pyrene derivatives potentially have interesting multifunctional properties such as electrochromic and electrofluorochromic characteristics. In this work, mono-, di-, tri-, and tetra-ester-substituted pyrene derivatives were synthesized, and the effects of the number of ester substituents on their photophysical, electrochemical, electrochromic, and electrofluorochromic properties were investigated. The number of ester substituents significantly affected these properties. An increase in the number of ester substituents on the pyrene caused red shifts in the absorption and emission spectra, a decrease in the driving voltage , and changes in the electrochromic colored states and electrofluorochromic performance. Mono-, di-, and tri-ester-functionalized pyrene derivatives showed good electrochromic properties, namely good switching stabilities, high optical contrasts, rapid responses, and high coloration efficiencies. Mono- and tri-ester-functionalized pyrenes gave good electrofluorochromic performances with reversible fluorescence quenching–fluorescence restoring between colored and bleached states during the electrochromic process. Ester-functionalized pyrene derivatives were successfully used in two functional digital displays with vivid colors. These results show that ester-functionalized pyrene derivatives with good electrochromic and electrofluorochromic properties are promising candidates for use in various applications, e.g., digital displays, organic electroluminescence displays, electronic shelf labels, energy-saving windows, and electronic paper.
Four imidazolium ionic liquids (ILs) with vinyl and ester groups were synthesized and characterized by 1H NMR, 13C NMR, and element analysis. The refractive index, electrical conductivity (EC), and electrochemical stability window (ESW) of the ILs were determined. The effect of the alkyl chain length of the ester group and anions on electrochemical properties was analyzed by density functional theory (DFT) calculations. At the same temperatures, the EC of the ILs decreased with the increase of the alkyl chain length. The ester group and vinyl group of cations showed a negative effect on the EC. The ESW increased with the increase of the alkyl chain length. The introduction of the ester group and vinyl group decreased the cathodic limiting potential of ester-based vinylimidazolium cations. DFT simulations showed that the structure of the IL was closely related to the EC and ESW. The average hydrogen bond length increased with the increase of the alkyl chain length of the ester group. The absolute interaction energy of ILs decreased with the increase of the alkyl chain length. Introduction of the vinyl group and ester group into the imidazolium cation resulted in a stronger cation–anion interaction, strengthening the ion mobility and charge transfer, resulting in a lower EC. The information is useful for the design and optimization of ILs as electrolytes for energy storage applications.
危险品化学品经营许可证（带存储）