Simple Organic Host/Guest Room Temperature Phosphorescence Materials and Their Application in Security Printing

Recently, the research of organic room temperature phosphorescence (RTP) materials has become a research hotspot in the field of materials science and chemistry, especially the use of a small molecule doping system to achieve long life and efficient RTP. Herein, an efficient stimulus responsive room temperature phosphorescent material is prepared by a simple host/guest eutectic method. Due to the high crystallinity of the host matrix, it provides a rigid environment for the guest emitter, and the appropriate triplet energy level provides a bridge for the energy transfer of the guest emitter. The prepared crystal material has a long lifetime of RTP with a lifetime of 0.82 s and a phosphorescence quantum yield of 12.3%. In addition, the introduction of fluorescent dyes in the eutectic system can adjust the afterglow color through energy transfer from triplet to singlet. Interestingly, the RTP properties of this material are sensitive to alkaline environments because it can destroy the crystalline structure of the host molecule, thereby reducing the rigidity of the entire system. Finally, the multicolor display and anticounterfeiting encryption of printed patterns are successfully applied by using the characteristics of afterglow color change and alkali response of doped materials.