Dual Multi-Resonance green emitter with steric shielding and core distortion for Solution-Processed TADF-OLEDs

Chemical Engineering Journal, Journal Year: 2025, Volume and Issue: unknown, P. 160139 - 160139

Published: Feb. 1, 2025

Language: Английский

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Intramolecular-Locking Modification Enables Efficient Asymmetric Donor-Acceptor-Donor’ Type Ultraviolet Emitters for High-Performance OLEDs with Reduced Efficiency Roll-Off and High Color Purity

Chemical Science, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 1, 2025

Developing high-performance ultraviolet organic light-emitting diodes with low efficiency roll-off and high color purity remains challenging due to their inherent wide-bandgap characteristics. In this work, we present an intramolecular noncovalent bond locking strategy modulate donor-acceptor-donor' (D-A-D') type fluorophores (mPImCZ2F, mPIoCZ2F mPImCP2F) a hot-exciton mechanism. Notably, these asymmetric emitters exhibit significantly enhanced bipolar transport capacity fluorescence compared counterparts. Among them, exhibits more remarkable effect multiple C-H⋯F interactions ortho-substitution-induced steric hindrance, which endows it higher radiation rate, narrower emission spectrum, balanced charge transport. Consequently, the mPIoCZ2F-based non-doped device achieves electroluminescence (EL) peak at 393 nm maximum external quantum (EQE) of 6.62%. Moreover, in doped device, emits stable light EL 391 full width half (FWHM) 40 nm, corresponding coordinates (0.167, 0.025). It also exceptionally EQE 8.71% minimal (7.95% 1000 cd m-2), ranking among best efficiencies reported for UV-OLEDs brightness levels.

Language: Английский

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Emission Wavelength and Efficiency Tuning of Monoatomic Multiresonance Emitters Using a Multiresonance Manager

Advanced Optical Materials, Journal Year: 2025, Volume and Issue: unknown

Published: March 26, 2025

Abstract A molecular design strategy for managing the emission energy and levels while enhancing efficiency of monoatomic multiresonance (MR) emitters based on a fused indolocarbazole (ICz) chromophore is developed by introducing cyano (CN) unit as an MR manager. The manager intensifies short‐range charge transfer character ICz‐based blue emitter, resulting in pure‐blue with narrow spectrum enhanced photoluminescence quantum yield. As result, CN manager‐modified ICz derivative demonstrates high external (EQE) 23.1%, small full width at half maximum 22 nm, color coordinate (0.142, 0.061). In addition, introduction enables fabrication phosphor‐sensitized fluorescence device EQE 24.6% maintaining spectrum.

Language: Английский

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Narrowband Emissive Solution‐Processed Polymer Organic Light‐Emitting Diodes with External Quantum Efficiency Above 30%

Advanced Materials, Journal Year: 2025, Volume and Issue: unknown

Published: March 27, 2025

Abstract Achieving both high‐efficiency and narrowband emission in thermally activated delayed fluorescence (TADF) polymers remains a formidable challenge. In this work, proof of concept for narrowband‐emissive TADF with partially conjugated structure is proposed by embedding silicon─carbon σ‐bond saturated spacer between the multiresonance (MR) unit polycarbazole backbone. A series PSix ( x = 1, 3, 6) then prepared characterized. All show full width at half maximum (FWHM) values 28–30 nm toluene solution. Impressively, polymer PSi3 has highest photoluminescence quantum yield, reaching 97%, doped films due to efficient reverse intersystem crossing process. The solution‐processed devices based on exhibit best performance external efficiency EQE max ) 28.8% an FWHM 42 nm. By employing molecule 5Cz‐TRZ as sensitizer, enhanced device 30.2% achieved, which first tier among MR‐TADF reported date. This work provides effective strategy achieving highly controlling chromophore

Language: Английский

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Rational Design of High-Efficiency Deep-Blue Multi-Resonance Thermally Activated Delayed Fluorescence Materials with CIEy < 0.06 and Narrowband Emission

Industrial & Engineering Chemistry Research, Journal Year: 2025, Volume and Issue: unknown

Published: May 8, 2025

Language: Английский

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Comprehensive Review on the Structural Diversity and Versatility of Multi-Resonance Fluorescence Emitters: Advance, Challenges, and Prospects toward OLEDs

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

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Linear Annulation Engineering of Indolocarbazole Multiple Resonance Emitter to Overcome Efficiency‐Stability‐Color Purity Trilemma in Deep‐Blue OLEDs

Advanced Materials, Journal Year: 2025, Volume and Issue: unknown

Published: May 9, 2025

Abstract Deep‐blue emitters for organic light‐emitting diodes (OLEDs) still confront the critical challenge of balancing high efficiency, operational stability, and color purity, particularly ones with peak wavelengths ( λ max ) ≤ 460 nm. Here, study demonstrates deep‐blue devices featuring ultrapure emission = 458 nm, full‐width at half‐maximum 19 nm), maximum external quantum efficiency 34.3% small roll‐off (26.9% 1 000 cd m − 2 ; 20.9% 5 ), long LT80 (time to 80% initial luminance) 101 hours 1,000 , being one longest lifetime among OLEDs nm EQE >20%. This breakthrough stems from an indolocarbazole narrowband emitter employing a linear annulation strategy, which not only narrows spectral bandwidth while red‐shifting through multiple resonance framework extension, but also energetically dynamically enhances device longevity via triplet energy reduction. Furthermore, strategic integration steric hindrance on emitting backbone suppresses intermolecular interactions directs reactivity pathways. concurrently achieves 456 FWHM 15 photoluminescence (PL) yield 98% in dilute toluene. The work highlights engineering as potential approach resolve efficiency‐stability‐color purity trilemma OLEDs.

Language: Английский

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Deep‐Blue Narrowband OLEDs Achieve External Quantum Efficiency Over 40% and Blue Index of 422 by Synergistic π‐Extension and Heavy‐Atom Effect

Advanced Materials, Journal Year: 2025, Volume and Issue: unknown

Published: May 19, 2025

Abstract Multi‐resonance thermally activated delayed fluorescence (MR‐TADF) emitters hold great promise for high‐resolution OLEDs, yet achieving both ultranarrow emission and efficient triplet utilization in the deep‐blue region remains challenging. Here, a synergistic molecular design is reported that combines π‐extension heavy‐atom incorporation to effectively reconcile trade‐off between color purity fast reverse intersystem crossing (RISC). In this approach, narrows bandwidth reduces singlet–triplet energy gap, while strategic introduction of chalcogen atoms selectively enhances spin–orbit coupling with minimal impact on spectrum. As result, new emitter exhibits peak at 453 nm an exceptionally narrow full width half maximum (FWHM) 17 high RISC rate constant 3.0 × 10 6 s −1 . When incorporated into non‐sensitized OLED, meets European Broadcast Union (EBU) standard CIE coordinates as low (0.140, 0.059), sustains brightness exceeding 30,000 cd m −2 Notably, device achieves record‐high external quantum efficiency (EQE max ) 40.5% roll‐off—retaining 38.4% 28.2% 100 1,000 , respectively—and attains Blue Index (BI) 422 A y These findings highlight effectiveness our tactic overcoming prior limitations where doping often compromises purity, paving way next‐generation advanced display lighting applications.

Language: Английский

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B─N Covalent Bonds and Twin‐Spiro Fused Design Strategy for the Construction of Narrowband Multiple Resonance Emitters

Advanced Functional Materials, Journal Year: 2025, Volume and Issue: unknown

Published: May 29, 2025

Abstract Developing the modified skeleton of multi‐resonance thermally activated delayed fluorescence (MR‐TADF) emitters can feasibly regulate their optoelectronic properties. However, research on MR‐TADF materials incorporating B─N covalent bonds remains relatively limited. Herein, a strategy is first proposed utilizing twin‐spiro conformation, dispirofluorene acridine (DSAF), via amine‐directed double borylation for framework fusion to construct emitters, DSAF‐TBDPA and DSAF‐TBCz. are employed enhance structural rigidity molecular framework. Furthermore, introduction structure imparts steric hindrance, thereby weakening π – interactions mitigating exciton quenching. As result, DSAF‐TBCz exhibit narrowband emission with full width at half maximum 20 19 nm. The doped organic light‐emitting diodes (OLEDs) based external quantum efficiencies (EQE max ) 27.2% 30.8%, respectively. These results underscore that design tactics not only expand diversity MR frameworks but also deliver critical insights high‐performance OLED emitters.

Language: Английский

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Weak emissive D-O-A organic phosphor: exceptional matrix-free sensitization in MR-TADF OLEDs

Research Square (Research Square), Journal Year: 2024, Volume and Issue: unknown

Published: Nov. 25, 2024

D-O-A organic phosphors showing strong aggregation-induced room-temperature phosphorescence (RTP) have been successfully demonstrated as the ideal matrix-free sensitizers for MR-TADF OLEDs. However, weak emissive ones still remain unexplored according to a habitual thinking that best sensitizer should be emitter. Herein, poor RTP emitter named RTP-D3 is newly developed based on carbazole donor, triazine acceptor and oxygen bridge. In spite of extremely low photoluminescence quantum yield, can sensitize terminal molecules effectively universally because favored intermolecular interactions thus balanced charge transport. Consequently, high performance sky-blue, green red narrowband electroluminescence realized together with state-of-art external efficiency 22.2% (49.2 cd/A, 55.2 lm/W), 31.5% (105.1 113.9 lm/W) 29.7% (55.4 66.9 well Commission Internationale de l’Eclairage (CIE) coordinates (0.12, 0.48), (0.26, 0.70) (0.61, 0.39), respectively. The exceptional results break conventional blind spot about sensitizer, highlighting less are also suitable sensitization in

Language: Английский

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