A High Contrast Tri-state Fluorescent Switch: Properties and Applications

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• 作者：Xing Su ; Yi Wang ; Xiaofeng Fang ; Yu-Mo Zhang ; Ting Zhang ; Dr. Minjie Li ; Dr. Yifei Liu ; Dr. Tingting Lin and Dr. Sean Xiao-An Zhang
• 刊名：Chemistry – An Asian Journal
• 出版年：2016
• 出版时间：November 22, 2016
• 年：2016
• 卷：11
• 期：22
• 页码：3205-3212
• 全文大小：2362K
• ISSN：1861-471X

文摘

A high contrast tri-state fluorescent switch (FSPTPE) with both emission color change and on/off switching is achieved in a single molecular system by fusing the aggregation-induced emissive tetraphenylethene (TPE) with a molecular switch of spiropyran (SP). In contrast to most of the reported solid-state fluorescent switches, FSPTPE only exists in the amorphous phase in the ring-closed form owing to its highly asymmetric molecular geometry and weak intermolecular interactions, which leads to its grinding-inert stable cyan emission in the solid state. Such an amorphous phase facilitates the fast response of FSPTPE to acidic gases and induces the structural transition from the ring-closed form to ring-open form, accompanied with the “Off” state of the fluorescence. The structural transition leads to a planar molecular conformation and high dipole moment, which further results in strong intermolecular interactions and good crystallinity, so when the acid is added together with a solvent, both the ring-opening reaction and re-crystallization can be triggered to result in an orange emissive state. The reversible control between any two of the three states (cyan/orange/dark) can be achieved with acid/base or mechanical force/solvent treatment. Because of the stable initial state and high color contrast (Δλ=120 nm for cyan/orange switch, dark state Φ_F<0.01 %), the fluorescent switch is very promising for applications such as displays, chemical or mechanical sensing, and anti-counterfeiting.