Fig. 1

a) Normalized absorption and emission spectra of TPASe and TPAS (5 µM) in 1,4-dioxane solution. b) Fluorescence emission spectra of TPASe in different solutions (λex = 488 nm). c) Quantum yield of TPASe in various polar solvents. d) Trend plot of fluorescence lifetime of TPASe in different polar solvents. e) Relative fluorescence intensity of TPASe as a function of the 1,4-dioxane/water mixture composition, with 1,4-dioxane increase from 0% to 100%. f) Fluorescence intensity plots of TPASe with the dielectric constant in the range of ε = 2.21 (1,4-dioxane) to ε = 25.58 (Vwater/V1,4-dioxane = 3:7). g) Fluorescence quantum yield of TPASe in 1,4-dioxane with varying water content (the dielectric constant changes from 2.21 to 25.58). h) Fluorescence lifetime spectra of TPASe in 1,4-dioxane/water mixture with different dielectric constants. i) HOMOs and LUMOs were plotted based on the optimized S0 (ground state) and S1 (excited state) geometries of the TPASe in 1,4-dioxane medium. j) HOMOs and LUMOs were plotted based on the optimized S0 and S1 geometries of the TPASe in H2O medium. k) Noncovalent interaction (NCI) index for hydrogen bond and van der Waals interactions of TPASe calculated at the B3LYP/6-31+G(d) in H2O and 1,4-dioxane. d, dipole moment.