Organic luminogens with persistent room temperature phosphorescence
(RTP) have drawn tremendous attentions due to their promising potentials
in optoelectronic devices, information storage, biological imaging, and
anti-counterfeiting. In this work, six triazatruxene-based lumiogens
with different peripheral substituents and configurations are
synthesized and systematically studied. The results show that their
fluorescence quantum yields in solid states range from 15.73% to
37.58%. Dispersing the luminogens as guest into the host
(PPh3) could turn on the persistent RTP, where
PPh3 acts as not only a rigid matrix to suppress the
non-radiative transitions of the guest, but also provides energy
transfer channels to the guest. The maximum phosphorescence efficiency
and the longest lifetime could reach 29.35% and 0.99 s in co-crystal
films of 6-TAT-CN/PPh3 and 5-TAT-H/PPh3,
respectively. Moreover, these host-guest co-crystalline films exhibit
great potentials in advanced dynamic data encryption and
anti-counterfeiting. This work deepens the insight for low cost,
halogen-free, and facile fabrication of all-organic persistent RTP
materials.
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