The Effect of Electron Donation and Intermolecular Interactions on Ultralong Phosphorescence Lifetime of 4‑Carnoyl Phenylboronic Acids

Purely
organic phosphors with persistent room-temperature phosphorescence
(RTP) demonstrate promising potential applications in optoelectronic
area, bioimaging, and chemical sensing. However, it is still a formidable
challenge to further design new organic phosphors due to the unclear
mechanism to produce ultralong phosphorescence lifetimes. This paper
investigates the correlation between the ultralong phosphorescence
lifetime and structure of a series of 4-carbonylphenylboronic acid
derivatives in the crystal state. Experimental and calculation results
reveal that the electron-donating effect of substituents makes the
phosphorescence lifetime longer by not only weakening the vibration
relaxation of the excited triplet state but also increasing the energy
of T1. Moreover, numerous intermolecular interactions for
reducing nonradiative relaxation and the degree of the π–π
stacking for stabilizing the triplet state are beneficial to the persistent
RTP. The work is conducted to clarify the structure–property
correlation of phosphorescent materials and design new persistent
phosphors. Finally, an attempt is completed using phosphorescent materials
to design two-dimensional or three-dimensional codes and anticounterfeiting
applications.