Facile synthesis of a near-infrared fluorophore based on Dibenzo[def,mno]chrysene-6,12-dione acceptor for dual applications in organic light-emitting diode and cellular imaging.

Near-infrared (NIR) fluorophores, characterized by emission wavelengths exceeding 650 nm, have garnered significant attention due to their diverse and advanced applications in fields such as organic light-emitting diodes (OLEDs), photomicrography, anti-counterfeiting, in vivo/vitro bioimaging, as well as theranostics. In this study, we report the rational design and facile synthesis of a novel NIR fluorescent molecule, AA-TPA, strategically constructed by integrating two twisted triphenylamine (TPA) electron-donating groups with a dibenzo[def,mno]chrysene-6,12-dione (AA) electron-accepting unit. The pronounced donor-acceptor interaction within the non-planar and rigid molecular architecture facilitates NIR emission with a peak at 667 nm, while preserving efficient luminescence with a photoluminescence quantum yield of 46 % in a doped film. Theoretical calculations reveal a small energy gap of 0.02 eV and a high spin-orbit coupling matrix element of 0.32 cm-1 between the lowest singlet and second triplet excited states, which enables the utilization of triplet excitons through a high-lying reverse intersystem crossing mechanism. Utilizing AA-TPA as the emitter, we have fabricated high-performance NIR OLEDs, delivering maximum external quantum efficiencies ranging from 2.19 to 4.24 %, with electroluminescence peaks at 676-710 nm. Additionally, AA-TPA nanoparticles possess remarkable biocompatibility and efficient cellular uptake, predominantly localizing within the endoplasmic reticulum of HGC27 cells for NIR bioimaging. This work provides a dual-functional NIR material with potential applications in both optoelectronic and biomedical fields.