Facile Synthesis of a Terephthalic Acid-Based Organic Fluorophore with Strong and Color-Tunable Emission in Both Solution and Solid States for LED Applications

Dual-state emission (DSE) fluorophores with strong photoluminescence in both solution and solid states have wide applications in fluorescent probes and photoelectric devices. However, most of the existing DSE fluorophores involve complex synthetic strategies or only one or two emission colors in the solid state, which may hinder their practical applications. Herein, we report a facile and effective strategy to fabricate a kind of novel adjustable DSE fluorophore TPAA–Cu based on the small molecule terephthalic acid (TPA) and ascorbic acid (AA) with CuCl2 as the catalyst. Not only can the TPAA–Cu solution emit blue, blue-green, and yellow colors depending upon the pH of solution, but also it shows reversible pH-tunable fluorescence colors. More importantly, corresponding TPAA–Cu solid fluorophores with blue, blue-green, and yellow colors can also be obtained with the quantum yields of 16.3, 26.7, and 29.6%, respectively.