The linkage-conversion synthesis was employed for the development of low-voltage near-infrared(NIR)electrochromic aminelinked covalent organic frameworks(COFs),enabling the sophisticated display of NIR concealed infor...The linkage-conversion synthesis was employed for the development of low-voltage near-infrared(NIR)electrochromic aminelinked covalent organic frameworks(COFs),enabling the sophisticated display of NIR concealed information.Two COF systems containing triphenylamine units connected by conjugated imine bonds were transformed into conjugation-broken amine-linked COFs through linkage reduction,allowing for precise modulation of their electrochemical and electrochromic properties.The electrochemical oxidation onset potential of the amine-linked COF film was significantly reduced by approximately 0.6 V,and their absorption in the NIR region exhibits a marked enhancement and blue shift during electrochemical oxidation.Combining experimental and computational approaches,this phenomenon was attributed the previously unreported short-range charge interactions between triphenylamine and adjacent amine groups.The amine-linked COFs exhibit low electrochromic driving voltages(0.2 V),sub-second response times,high coloration efficiency,and stable electrochromic-switch properties.Notably,the low-voltage-driven amine-linked COFs showed pronounced NIR color changes with non-apparent visible color changes,leveraging this characteristic to achieve concealed information display in the NIR region.This work demonstrates the importance of linkage engineering in the design and preparation of high-quality optoelectronic functional COF materials and highlights the great application potential of optoelectronic COFs.展开更多
基金supported by the National Natural Science Foundation of China(22005312,22375042)the Strategic Priority Research Program of Chinese Academy of Sciences(XDB0520201)+3 种基金the Southeast University Interdisciplinary Research Program for Young Scholars(2024FGC1007)the Young Elite Scientists Sponsorship Program by China Association for Science and Technology(2023QNRC001)the support of 1W1A endstation at Beijing Synchrotron Radiation Facility,Institute of High Energy Physics,Chinese Academy of Sciencessupported by the Big Data Computing Center of Southeast University。
文摘The linkage-conversion synthesis was employed for the development of low-voltage near-infrared(NIR)electrochromic aminelinked covalent organic frameworks(COFs),enabling the sophisticated display of NIR concealed information.Two COF systems containing triphenylamine units connected by conjugated imine bonds were transformed into conjugation-broken amine-linked COFs through linkage reduction,allowing for precise modulation of their electrochemical and electrochromic properties.The electrochemical oxidation onset potential of the amine-linked COF film was significantly reduced by approximately 0.6 V,and their absorption in the NIR region exhibits a marked enhancement and blue shift during electrochemical oxidation.Combining experimental and computational approaches,this phenomenon was attributed the previously unreported short-range charge interactions between triphenylamine and adjacent amine groups.The amine-linked COFs exhibit low electrochromic driving voltages(0.2 V),sub-second response times,high coloration efficiency,and stable electrochromic-switch properties.Notably,the low-voltage-driven amine-linked COFs showed pronounced NIR color changes with non-apparent visible color changes,leveraging this characteristic to achieve concealed information display in the NIR region.This work demonstrates the importance of linkage engineering in the design and preparation of high-quality optoelectronic functional COF materials and highlights the great application potential of optoelectronic COFs.
