Science China Chemistry, Journal Year: 2024, Volume and Issue: unknown
Published: Oct. 23, 2024
Language: Английский
Chemical Science, Journal Year: 2025, Volume and Issue: unknown
Published: Jan. 1, 2025
Multi-resonance thermally activated delayed fluorescence (MR-TADF) emitters have been actively employed in high-resolution solution-processed organic light emitting diodes (OLEDs) due to their excellent color purity. Nonetheless, they are always confronted with intrinsic slow spin flip of triplet excitons, impeding the electroluminescence properties, especially non-sensitized OLEDs. Herein, we constructed intramolecular charge transfer (ICT) assisted MR-TADF by grafting donor-acceptor-type moieties a meta- or para-substitution as pendant on an organoboron multi-resonance core. The newly designed not only maintain short range characteristics emissive states without sacrificing purity but accelerated flips facilitated ICT process at high-lying state also confirmed ultrafast spectroscopy and theoretical calculation, achieving over 10-fold increase reverse intersystem crossing rate compared unsubstituted counterpart emitters. In sensitizer-free OLEDs, cutting-edge external quantum efficiency 27.8% can be achieved together reduced roll-offs attractive full width half maximum 29 nm, representing breakthrough for based narrowband
Language: Английский
Citations
0
Advanced Optical Materials, Journal Year: 2025, Volume and Issue: unknown
Published: Feb. 5, 2025
Abstract Introducing heavy atoms to enhance spin‐orbit coupling represents an effective strategy for boosting the reverse intersystem crossing (RISC) rate constants of Multi‐resonance thermally activated delayed fluorescence (MR‐TADF) emitters. Nevertheless, restricted diversity molecular structures obstructs a thorough investigation structure‐property relationships, thereby limiting improvement device performance, especially in case solution‐processed devices. Herein, alkylthio‐substituted carbazole building block is designed and developed two new MR‐TADF emitters, namely BNCz‐2S BNCz‐4S. Quantum simulations photophysical studies have revealed that as number sulfur increases, BNCz‐4S exhibits higher photoluminescence quantum yield (PLQY), smaller singlet‐triplet energy gap (Δ E ST ) reorganization energy, along with larger (SOC) constant ( k RISC compared BNCz‐2S. Consequently, solution‐processing devices based on exhibit external efficiency (EQE) 24.06%, which first tier reported organic light‐emitting diodes (OLED) date.
Language: Английский
Citations
0
Science China Chemistry, Journal Year: 2025, Volume and Issue: unknown
Published: March 25, 2025
Language: Английский
Citations
0
Aggregate, Journal Year: 2024, Volume and Issue: unknown
Published: Sept. 25, 2024
Abstract Circularly polarized luminescence (CPL) materials with delayed fluorescence have attracted much attention due to their ability efficiently trap triplet state excitons, thereby improving the photoluminescence quantum yields of CPL materials. However, effort has been normally focused on utilization T 1 excitons but seldom higher excited n ( > 1) excitons. Rational manipulation and suppression Kasha's rule remains a major challenge. Herein, two gold complex enantiomers (( R / S )‐BPAuBC) based axially chiral binaphthyls 3,6‐Di‐tert‐butylcarbazole groups are synthesized systematically investigated. These exhibit aggregation‐induced circularly fluorescence. was found be enabled by activating high‐level reverse intersystem crossing (hRISC). The anti‐Kasha phosphorescence at 77 K proves that exciton large population in high‐lying 2 , which allows effective hRISC process cross back singlet emit In addition, “on–off” switching is further achieved nanoparticles acid–base stimulus, showing its potential as an responsive material.
Language: Английский
Citations
3
Science China Chemistry, Journal Year: 2024, Volume and Issue: unknown
Published: Oct. 23, 2024
Language: Английский
Citations
1