Published: Jan. 1, 2024
Language: Английский
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
Advanced Optical Materials, Journal Year: 2025, Volume and Issue: unknown
Published: March 17, 2025
Abstract Advanced cutting‐edge organic light‐emitting diode (OLED) technologies require narrowband electroluminescence (EL) with high quantum efficiency to growing performance demand. Here, sequential indolo‐fusion π‐extension as a rational design strategy further narrow the emission bandwidth of multi‐resonance thermally activated delayed fluorescence (MR‐TADF) is introduced. By fusing one or two additional indole moieties periphery Cz‐B, typical MR‐TADF motif, gradual spectra narrowing, and accelerated triplet–singlet exciton spin conversion are concurrently achieved. Suppressing vibronic couplings induced by high‐frequency vibrational modes vital for achieving extreme spectral narrowing. OLEDs based on doubly indolo‐fused emitter, IDCz‐B‐II, exhibited ultra‐narrowband sky‐blue EL full width at half maximum 21 nm (0.11 eV), external 25.9%, reduced roll‐off, significantly outperforming Cz‐B‐based device. The present provides simple yet promising approach developing isomeric materials different positions orientations.
Language: Английский
Citations
0
Chemical Reviews, Journal Year: 2025, Volume and Issue: unknown
Published: May 9, 2025
Fluorescence emitters with a multiple-resonant (MR) effect have become research hotspot. These MR mainly consist of polycyclic aromatic hydrocarbons boron/nitrogen, nitrogen/carbonyl, and indolocarbazole frameworks. The staggered arrangement the highest occupied molecular orbital lowest unoccupied facilitates MR, resulting in smaller internal reorganization energy narrower emission bandwidth. Optimal charge separation suppresses gap between singlet triplet excited states, favoring thermally activated delayed fluorescence (TADF). MR-TADF materials, due to color purity high efficiency, are excellent candidates for organic light-emitting diodes. Nevertheless, significant challenges remain; particular, limitation imposed by alternated core configuration hinders their diversity versatility. Most existing materials concentrated blue-green range, only few red near-infrared spectra. This review provides timely comprehensive screening from pioneering work present. Our goal is gain understandings structure-performance relationship both basic advanced perspectives. Special emphasis placed on exploring correlations chemical structure, photophysical properties electroluminescent performance depth breadth an aim promote future development emitters.
Language: Английский
Citations
0
Chinese Journal of Organic Chemistry, Journal Year: 2025, Volume and Issue: 45(4), P. 1119 - 1119
Published: Jan. 1, 2025
Language: Английский
Citations
0
Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown
Published: May 22, 2025
Achieving narrowband fluorescence in polycyclic aromatic hydrocarbons (PAHs) is crucial for ultrahigh-definition organic light-emitting diodes (UD-OLEDs), yet the underlying structure-property relationships that dictate emission bandwidth remain insufficiently understood. In this study, we introduce aromaticity localization as a predictive framework identifying emitters. Using nucleus-independent chemical shift (NICS) analysis, uncover strong correlation between localized and reduced vibrational coupling, demonstrating restricting π-electron delocalization effectively suppresses shoulder peaks, thereby minimizing spectral broadening. To validate concept, designed new class of imine-amine-type PAHs (IA-PAHs) integrates electron-deficient imine electron-rich amine units, generating multiple-resonance-type electronic structure. Building on steric-hindrance-guided C-H activation strategy, precisely controlled regioselectivity pyridine fusion within triphenylamine framework, leading to discovery red-emitting II-b green-emitting III-c featuring aromaticity. Notably, exhibited an exceptionally red at 660 nm with full width half-maximum only 35 (0.10 eV). OLEDs incorporating demonstrated high efficiency minimal roll-off fully met stringent BT.2020 standard, Commission Internationale de l'Eclairage (CIE) coordinates [0.71, 0.29]. This work not establishes empirical intuitive design principle fluorophores but also represents significant advancement deep-red OLED technology, setting benchmark conventional fluorescent
Language: Английский
Citations
0
Chemical Engineering Journal, Journal Year: 2025, Volume and Issue: unknown, P. 164120 - 164120
Published: May 1, 2025
Language: Английский
Citations
0
Advanced Optical Materials, Journal Year: 2025, Volume and Issue: unknown
Published: May 27, 2025
Abstract Materials exhibiting multiple resonance thermally activated delayed fluorescence (MR‐TADF) have attracted attention in organic electronics because of their high photoluminescence quantum yield and narrowband emission. While these superior properties are also desirable for probes biological imaging, MR‐TADF emitters yet to be broadly exploited this field. Here, the emitter QAO is incorporated into polymer nanoparticles construct imaging with emission fluorescence. A monomer QAO‐NB first designed by incorporating a norbornene polymerization handle onto core, which then backbone ring‐opening metathesis afford water‐dispersible fluorescent dots, or Pdots. Photophysical characterization confirmed that preserved both polymers Pdots (λ max = 467–478 nm, FWHM ≤ 50 nm), lifetime 455 µs Multichannel studies using comparisons against donor‐acceptor TADF materials underscore potential development emissive bioimaging probes.
Language: Английский
Citations
0
Materials Today Communications, Journal Year: 2025, Volume and Issue: unknown, P. 112941 - 112941
Published: May 1, 2025
Language: Английский
Citations
0
Advanced Materials, Journal Year: 2024, Volume and Issue: unknown
Published: Sept. 23, 2024
Abstract Due to the soliton‐like electronic structural characteristics, cyanine dyes typically exhibit spectral behaviors such as large molar extinction coefficients, narrow spectra, and high fluorescence efficiency. However, their extensive applications emitters in electroluminescence are largely ignored due serious emission quenching aggregation state. Herein, it is reported a squaraine dye (a type of cyanine) SQPhEt. At different solution concentrations, unusual decrease full‐width at half‐maxima (FWHM) with increasing Stokes shift indicates SQPhEt aggregated state because strong self‐absorption effect. A sensitized device structure can help reduce doping concentration dye, which effectively suppress self‐absorption. Benefitting from coefficient SQPhEt, even low concentrations 0.1 wt%, efficient Förster energy transfer be achieved. The corresponding spin‐coating based on dopant exhibits favorable deep‐red 668 nm small FWHM 0.10 eV.
Language: Английский
Citations
2
Chemical Engineering Journal, Journal Year: 2024, Volume and Issue: 501, P. 157676 - 157676
Published: Nov. 14, 2024
Language: Английский
Citations
2