Red-Shifted Emission in Multiple Resonance Thermally Activated Delayed Fluorescent Materials through Malononitrile Incorporation

Abstract

Multiple resonance thermally activated delayed fluorescent (MR-TADF) materials offer higher color purity than conventional TADF materials but suffer from aggregation-caused quenching (ACQ) and rarely exhibit red emission. Herein, two malononitrile-substituted emitters are synthesized from a quinolino­[3,2,1-de]­acridine-5,9-dione (QAO) MR-TADF precursor. Both materials maintain MR-TADF, while they display red-shifted fluorescence. They also overcome ACQ, displaying enhanced emission upon aggregation in solution and forming red-emissive J-aggregates in the solid state with photoluminescent quantum yields of 9 and 11%.

Type‐I Photodynamic Therapy Induced by Pt‐Coordination of Type‐II Photosensitizers into Supramolecular Complexes

“…Meanwhile, the electrochemical characterization of (Cz−BTZ−Py) 2 Pt(OTf) 2 was conducted by cyclic voltammetry (CV) (Figure S9) in DMF. And the electrochemical energy gap $${{E}_{g}^{ec}}$$ for (Cz−BTZ−Py) 2 Pt(OTf) 2 were calculated to be 1.65 eV, [38,39] which had good agreement with their optical energy gap. In the fluorescence emission spectra (Figure 2b), the supramolecular dimer (Cz−BTZ−Py) 2 Pt(OTf) 2 showed good emission in the NIR region, indicating the supramolecular dimer held great potential for use in NIR imaging.…”

Efficient orange organic light-emitting diodes employing a central aniline bridged multiresonant thermally activated delayed fluorescence emitter

“…12–15 However, examples of orange/red MR-TADF OLEDs remain relatively rare due to the challenges in emitter design to red-shift the emission of the emitters. 6 There are currently two primary methods for shifting the emission to the red: (1) Enhancing the donor and acceptor strength by constructing systems with electron-accepting (A) and donating atoms (D) in A- para -A and D- para -D regiochemistry; 16–19 (2) Decorating the MR-TADF core with donor or acceptor substituents to tune the energy of the emissive core; 20,21 note that the use of too strong donors or acceptors results in the excited state being of long-range charge transfer (LRCT) character, resulting in less bright and broader emission. Dimerization of MR-TADF emitters is a distinct strategy for realizing red-shifted emission via extending the conjugation area.…”