(1) Stern–Volmer
(S–V) plot (2D) obtained for (a)
all NACs and (b) second-order polynomial fitting of S–V plot
for TNT. (c) S–V equation for both static and dynamic quenching.
(2) (a) Time-resolved photoluminescence (TRPL) spectra of PFPy (6.66
μM) in the absence and presence of various concentration of
TNT in water containing 10 mM NaOH. (b) Change in lifetime at various
concentrations of TNT. (c) Equation (II) for dynamic quenching: where
τ and τo are the average fluorescence lifetime
with and without TNT, respectively. (3) (a) Spectral overlap between
the normalized PL spectrum [0–0.1] of CP PFPy with absorbance
of various NACs in water containing 10 mM NaOH. (b) Spectral overlapping
region between the normalized emission spectrum of PFPy with TNT in
water containing 10 mM NaOH. (c) Equations for RET parameters: (1)
Equation (III)-where J denotes overlap integral value, FD(λ) represents the corrected fluorescence
intensity from λ to Δλ with total fluorescence intensity
for PFPy normalized to 1, and εA represents molar
absorptivity of acceptor in M–1 cm–1. (2) Equation (IV)-where R0 represents
Förster distance, Q denotes the fluoresence
quantum yield of PFPy, η represents refractive index of the
medium, and k2 signifies dipole orientation
factor (0.667). (3) Equation (V)-where E% denotes
RET efficiency, τDA and τD are the
average fluorescence lifetime with and without quencher, i.e., TNT.