Intermolecular Charge-Transfer-Induced Strong Optical Emission from Herringbone H-Aggregates

Abstract

Luminescence in molecular aggregates can be quenched either by intermolecular charge transfer or by forming a dipole-forbidden lower Frenkel exciton in H-aggregate. Taking intermolecular charge transfer and excitonic coupling into a three-state model through localized diabatization, we demonstrate that the low-lying intermolecular charge-transfer state could couple with the upper bright Frenkel exciton to form dipole-allowed S1 that lies below the dark state, which accounts for the recent experimentally discovered strong luminescence in organic light-emitting transistors (OLETs) system with DPA and dNaAnt herringbone aggregates. The condition of forming such bright state is that the electron and hole transfer integrals, t e and t h, are of the same sign, and should be notably larger than the excitonic coupling (J), that is , t e × t h > 2J 2. This theoretical finding not only rationalizes recent experiments but unravels an exciting scenario where strong luminescence and high charge mobilities become compatible, which is a preferable condition for both OLETs and electrically pumped lasing.

Crystallization‐Enhanced Stability by Effectively Suppressing Photooxidation Defect for Optoelectronic Devices

“…This feature probably indicates that the self‐assembled nanorods effectively enhances the order of H‐aggregation behavior. [ 22 ] Further, the PLQY of DDC 3 F‐based nanorod film is measured as 87%, which is slightly lower than that in dilute solution (PLQY = 97%) but can be 1.5 times higher than that on amorphous film (57%) without crystalline morphologies (Figure 2b). Thus, such crystalline nanorod film enables to suppress general aggregation‐caused quenching effect and maintain the high efficient deep‐blue emission, seemingly analogous to the presence of CIEE feature.…”

Realization of Single-Phase White-Light-Emitting Materials with Time-Evolution Ultralong Room-Temperature Phosphorescence by Coordination Assemblies

“…This also demonstrated that the coordination-induced approach can greatly enhance the charge separation of the D−π–A chromophore and enhance the intermolecular charge transfer delayed emission. As a whole, the RTP behaviors originate from well-separated and aggregation-generated triplet emission. , …”

Theoretical insights into the central “acceptor” bridge function on the whole visible light and near-infrared emission in tetraphenylpyrazine-based luminogens

“…Finally, it should be mentioned that although the method we employed has achieved satisfactory results in mechanism explanation and property prediction, quantitative modulation of the luminescent behaviors of organic materials is still challenging. 32,[47][48][49][50]…”