Fig. 1: Absorption, fluorescence, delayed fluorescence, and phosphorescence of the investigated molecules. | Nature Communications

Fig. 1: Absorption, fluorescence, delayed fluorescence, and phosphorescence of the investigated molecules.

From: Rigid and planar π-conjugated molecules leading to long-lived intramolecular charge-transfer states exhibiting thermally activated delayed fluorescence

Fig. 1

a Molecular structures of the three charge-transfer emitters (p-ICz-PI, o-ICz-PI, and Cz-PI) studied in this work. The donor and acceptor units are shown in red and green colors, respectively. b Normalized absorption and steady-state emission spectra of dilute p-ICz-PI (top panel), o-ICz-PI (middle panel) and Cz-PI (bottom panel) solutions in methylcyclohexane, toluene and dichloromethane ([c] = 2 × 10−5 M). Inset shows the change in emission color upon changing the solvent polarity when excited at 365 nm by a UV-lamp. Phosphorescence (measured using time-gated emission at 80 K with a high time-delay of 80 ms) in 1 wt.% zeonex shown here to highlight the locally-excited nature of the T1 state in all three molecules. c Time-resolved emission spectra and (d) time-resolved decay of p-ICz-PI (room temperature) and o-ICz-PI (room temperature and 80 K) in degassed dichloromethane. λexc = 355 nm, [c] = 2 × 10−5 M. Three different regions of prompt fluorescence (PF), delayed fluorescence (DF) and phosphorescence (Phos.) are shown in Fig. 1d, with the DF completely quenched at 80 K.

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