Fig. 2: Photophysical properties of the TG-PD COF and its PFOA sensing efficiency.
a Normalized photoluminescence (PL) spectra (λex = 365 nm) of TG-PD COF dispersion in water with the stepwise addition of PFOA, b Linear plot of normalized PL intensity (λmax = 365 nm) as a function of PFOA concentration, c Bar graph illustrating the comparative fluorescence intensity of TG-PD COF in the presence of different analytes, where I0 is the initial intensity of TG-PD COF, and I is the final intensity in response to each analyte, d Solid state 13C CP/MAS NMR spectra of PFOA (black line), TG-PDCOF (green line) and TG-PD COF and PFOA (red line). Asterisks denote spinning side bands. e Overlay of the two-dimensional 1H−13C HETCOR solid-state NMR spectra of pure PFOA (red contour, red dotted circle) and PFOA bound to TG-PD COF (black contour, gray oval). Inset shows the simplified chemical structures of TG-PD COF and PFOA. Intramolecular 1H−13C correlation from pure PFOA is shown by green arrow and inter-molecular correlation between PFOA and TG-PD COF is shown by a red arrow. Upfield chemical shift change for the carbonyl carbon from PFOA upon binding to TG-PD COF is shown by a green arrow.
