Table 1 PL characteristics and rate constants of CzBN and CzPN derivatives in solution and doped film.
MaterialΦPL Air*
(%)
ΦPL Degassed*
(%)
ΦPL Solid film
(%)
τprompt
(ns)
τDF
(μs)
Embedded Image‡§
(×107 s−1)
kRISC‡§
(×105 s−1)
kISC‡§
(×108 s−1)
Embedded Image‡§
(×104 s−1)
ΔEST‡║
(eV)
2CzBN152310.91.31.400.878.30.21
o-3CzBN213126/3318.5151.100.46.50.21
m-3CzBN151733/263.6394.202.42.60.24
p-3CzBN101435/311.2358.30.127.52.70.22
4CzBN96294/761.6365.61.85.71.70.22
5CzBN98589/783.8392.42.42.40.420.17
2CzPN42.346.589**27281.60.060.213.60.21
4CzIPN109482**164.60.6320.30.561.50.04

*PLQY at a concentration of 10−4 M in toluene.

†PLQY for PPT host matrix doped with 3 wt % (left) or 15 wt % (right) of the emitter.

‡Solution samples.

§Rate constant of radiative decay of singlets Embedded Image, Embedded Image, kRISC, and kISC of the solution samples determined by the method described by Masui et al. (18).

║Energy gap calculated from S1 and T1 energy levels estimated from the threshold of fluorescence spectra and peak (2CzBN) or threshold (others) of phosphorescence spectra (Fig. 2B), respectively. The error is ±0.03 eV. The data of fluorescence and phosphorescence spectra of 2CzPN and 4CzIPN are depicted in fig. S7.

¶Virtual values as determined by measuring a time profile of decay curve of triplet state absorption bands in microsecond-TAS (see figs. S1 and S8).

**Value of 2CzPN-mCP [1,3-bis(N-carbazolyl)benzene] (6 wt %) by Masui et al. (18) and of 4CzIPN-CBP (4,4-N,N′-dicarbazole-biphenyl) (6 wt %) by Uoyama et al. (5).