Fig. 3: Spectroscopic characterization of CTFs.
From: Red edge effect and chromoselective photocatalysis with amorphous covalent triazine-based frameworks
a Optical absorbance spectra of PHT and PYT. Some discontinuous data points caused by the change in detector at ~900 nm were removed. b Band structure of PHT and PYT. c PL spectra of PHT. λexc (in nm) is shown. d PL spectra of PYT. λexc (in nm) is shown. e Amplitude average lifetime (\(\bar{{{{{{\rm{\tau }}}}}}}\)) of PHT and PYT obtained at λexc = 375, 470, and 640 nm and λem = 400–900 nm. f EPR spectra of PHT and PYT at room temperature in the dark and under light (λexc = 455 nm) irradiation (~40 min). Dashed and solid curves show the raw and fitted data, respectively. g Band structure of PHT and PYT. Vertical plain lines indicate separation of holes and electrons and their radiative recombination; horizontal and diagonal wavy lines – migration of holes and electrons to surface states, respectively. Schematically thickness of the vertical lines illustrates the rate of photogenerated charge carriers separation (in relation to e): the thinner the line the faster is the separation of charge carriers. Schematic representation of the density of states of emissive intraband states based on the data of steady-state PL (c and d). Nonbonding N orbitals in the structure of PHT and PYT that contribute to the intraband states are schematically shown by the fragments of triazine and triazine-pyridine-diyl linkers.
