Heptamethine cyanine dye-based functionalized recyclable flexible cotton fabric platform for the colorimetric and real-time ultrasensitive detection of gaseous BF3

Abstract

In this paper, a near infrared heptamethine cyanine dye of BK-Cy for boron trifluoride (BF3) detection was developed based on the Lewis acid-base reaction mechanism. BF3 bounded to the diphenylamine group in the middle of the heptamethine backbone structure forming Lewis acid-base complexes with decreasing fluorescence at λem = 830 nm (λex = 780 nm) and increased absorbance between 500 and 700 nm, making obvious color changes from light green to dark blue. BK-Cy showed excellent properties including rapid response (<1 min), lowest detection limit (1.73 nM), excellent linearity (R2 = 0.9903) and specific selectivity. Meanwhile, a functionalized recyclable flexible cotton fabric platform of BK-Cy@cotton was fabricated and assembled with a smartphone to form a portable detecting platform to monitor the color changes of BK-Cy for quantitative BF3 detecting in gas phase under visible light. The real-time visualization of the remodeling BK-Cy@cotton platform from BK-Cy through dynamic covalent bonding was completely recyclable, environmentally friendly and had the possibility for future practicability applications.