Deep-Red/Near-Infrared Electroluminescence from Single-Component Charge-Transfer Complex via Thermally Activated Delayed Fluorescence Channel

Formation of a single-component charge-transfer complex (SCCTC) is unveiled in solid state of an intermolecular charge-transfer molecule 2-(4-(1-phenyl-1H-phenanthro[9,10-d]imidazol-2-yl)phenyl)anthracene-9,10-dione (PIPAQ). Intermolecular donor-acceptor interactions between two PIPAQ molecules is the primary driving force for self-association and contributes to intermolecular charge transfer. The SCCTC character is fully verified by crystallographic, photophysical, electron spin resonance, and vibrational characterizations. The PIPAQ-based SCCTC is first applied in light-emitting devices as an emissive layer to realize efficient deep-red/near-infrared electroluminescence. This work provides new insights into SCCTC and represents an important step toward their applications in optoelectronic devices.