The Stacking Induced Organic Room Temperature Phosphorescence: A Compact Weak Interaction Mechanism

The origin and red-shift of organic room temperature phosphorescent (RTP) emission are indistinct. Deeply theoretical investigations based on appropriate model are urgent to reveal the two aspects. In this work, Br-AnCp derivatives with various stacking kinds were investigated by density functional theory and the "oxygen" effect in cyclopentane group were also considered to understand the origin and red-shift of RTP emission. The results show that the phosphorescent emission of Br-An-Cp derivatives was induced by compact intermolecular interactions and the "oxygen" effect was not dominated. An evolved complex supramolecular electron transition appears along with the shorting molecular stacking distance, which not only enhances the ISC process but also induces a red-shift of emission. Ours works indicate that the phosphorescent emission of organic materials can be strengthened by the special condition, such as crystal state with dense molecular stacking, high pressure environment and so on.