Multi-responsive red solid emitter: Detection of trace water and sense of relative humidity

• DOI: 10.1007/s40843-018-9371-y
• Publication Date: 2018-11-16T18:59:49Z
• Authors: Yuqi Cao; Ligong Chen; Dongqi Liu; Bowei Wang
• Keywords: Triphenylamine; Tetrahydrofuran; Naked eye; Solvatochromism

A multi-responsive D-A type compound ( CYQ ) based on pyrone and triphenylamine was designed and successfully synthesized. The target compound exhibited distinct aggregation-enhanced emission (AEE) effect. Solvatochromic experiment and density functional theory (DFT) indicated CYQ possessed excellent intramolecular charge transfer (ICT) ability. Besides, its mechanofluorochromic property (MFC) was found with a 37 nm red-shift. Powder wide-angle X-ray diffraction (PXRD) and differential scanning calorimetry (DSC) measurements were performed to demonstrate the transformation from the crystalline to amorphous states upon grinding. Surprisingly, CYQ displayed a hypersensitive response to trace water in organic solvents with an excellent detection limit as low as 0.0096% in tetrahydrofuran (THF). Furthermore, it was found that the fluorescent intensity of CYQ declined progressively upon humidity rise, and its color change can be witnessed by naked eyes. Therefore, the relative humidity (RH) sensing strategy guarantees the AIEgen to become a colorimetric sensor under various conditions.