Fig. 3. Optical characterization of G-TXr-TIPS-AnS-PdTPBP film. (a) Absorption (dotted lines) and PL (solid lines) spectra of the G-TXr-TIPS-AnS (blue line, λex = 415 nm, TIPS-AnS = 200 μmol kg−1) and G-TXr-PdTPBP (red line, λex = 633 nm, 27 μmol kg−1) films in the air. (b) Photograph of G-TXr-TIPS-AnS-PdTPBP film under white light, and (c) under 633 nm laser excitation in the air (excitation intensity = 1.3 W cm−2, no short pass filter used). (d) Comparative PL spectra of G-TXr-PdTPBP-TIPS-AnS films at different concentrations of TIPS-AnS (1, 2.5 and 5 mmol kg−1) upon 633 nm laser excitation (excitation intensity = 33.8 mW cm−2). (e) Comparative log–log plot of excitation intensity dependence of UC emission intensity of G-TXr-TIPS-AnS-PdTPBP films at different concentrations of TIPS-AnS. (f) Time traces of normalized upconversion emission intensity of G-TXr-TIPS-AnS-PdTPBP sample-III for various excitation intensities in the air (λex = 633 nm laser, λem = 478 nm). (g) Comparative internal UC quantum yield of G-TXr-TIPS-AnS-PdTPBP films in the air.
