The Effect of Electron-donation and Intermolecular Interactions on Ultralong Phosphorescence Lifetime of 4-carnoyl Phenylboronic Acid.

Purely organic phosphors with persistent room temperature phosphorescence (RTP) demonstrate promising potential application 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 lifetime. This paper investigates the correlation between ultralong phosphorescence lifetime and structure of a series of 4-carbonylphenylboronic acid derivatives in crystal state. Experimental and calculation results reveal that electron-donating effect of substituents makes phosphorescence lifetime longer by not only weakening vibration relaxation of excited triplet state, but also increasing the energy of T1, thus suppressing non-radiation transition. Moreover, numerous intermolecular interactions for reducing non-radiative relaxation and degree of the π-π stacking for stabilizing 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 2D or 3D codes and anti-counterfeiting application.