Abnormal homodirectional responses of magneto-phosphorescence and magneto-fluorescence in organic phosphorescent...

Molecular doping has emerged as a promising method for enhancing the performance of organic phosphorescent crystals. In this work, by incorporating third-component molecules with inactive phosphorescence into binary phosphorescent crystals, ternary phosphorescent crystals with an afterglow that is visible to the naked eye are constructed via the co-crystallization of three components. Energy transfer between the third component and ternary crystals is motivated by the incorporation of the third component, where this third component with an optimized concentration facilitated an 11-fold increase in phosphorescence lifetime of the ternary crystal. Notably, the phosphorescence is contributed by the radiative recombination of triplet excitons in the third component, leading to abnormal homodirectional responses of magneto-phosphorescence and magneto-fluorescence in phosphorescent crystals. Furthermore, under the stimuli of external magnetic fields, the magneto-phosphorescence and magneto-fluorescence processes compete with each other, and the competition is tightly dependent on the external light intensity. Overall, this study proposes a phosphorescence design method based on third-component incorporation and also provides an insightful understanding of the magneto-phosphorescence effect in organic ternary phosphorescent crystals.