Intramolecular charge transfer assisted multi-resonance thermally activated delayed fluorescence emitters for high-performance solution-processed narrowband OLEDs

Chemical Science, Год журнала: 2025, Номер unknown

Опубликована: Янв. 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

Язык: Английский

---

High‐Efficiency Solution‐Processed Organic Light‐Emitting Diodes Utilizing Multiple‐Resonance Emitters Incorporating Thiocarbazole Unit

Advanced Optical Materials, Год журнала: 2025, Номер unknown

Опубликована: Фев. 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.

Язык: Английский

---

Interplays between Functional Groups and Substitution Sites Modulate the Photophysics of the Bithiophenes

The Journal of Physical Chemistry A, Год журнала: 2025, Номер unknown

Опубликована: Фев. 17, 2025

Bithiophene has an electron-rich conjugated ring, enabling highly tunable photophysical properties for the design of novel organic light-emitting materials. Extensive research was focused on functionalization α-site-connected bithiophene, while recent work reported synthesis β-bithiophene, substantially enlarging chemical space bithiophene design. However, rule modulating physical β-bithiophene remained unexplored. We performed comprehensive quantum calculations to investigate how functional groups and substituent sites control absorption emission wavelengths β-bithiophene. Our results show that lead red-shifts by extending electron delocalization, substitution have fewer effects wavelengths. The calculation trithiophene tetrathiophene suggest thiophene polymer are controlled short chains, underscoring significance rational derivatives.

Язык: Английский

---

Lithium zincate-enabled divergent one-pot dual C–C bond formation in thiophenes

Chemical Communications, Год журнала: 2025, Номер unknown

Опубликована: Янв. 1, 2025

We present a lithium zincate-enabled, divergent one-pot synthesis for regioselective dual C-C bond formation in thiophenes. By modifying the zinc coordination environment, single set of reagents (ZnCl2, R1Li, and diethyl (5-halo)thenylphosphate) was found to generate two distinct products. This approach extends versatility organozincates CAr(sp2)-Cthienyl(sp2) Cthenyl(sp3)-CAr(sp2) couplings without requiring transition metals and/or arenes pre-activated with boronic acid.

Язык: Английский

---

Synergetic Multiple Charge‐Transfer Excited States for Anti‐Quenching and Rapid Spin‐Flip Multi‐Resonance Thermally Activated Delayed Fluorescence Emitter

Advanced Materials, Год журнала: 2025, Номер unknown

Опубликована: Март 29, 2025

The development of multiple resonances thermally activated delayed fluorescence (MR-TADF) emitters exhibiting high efficiency, narrowband emission, rapid reverse intersystem crossing rate (kRISC), and suppressed concentration quenching simultaneously is great significance yet a formidable challenge. Herein, an effective strategy presented to realize the above target by synergizing charge-transfer excited states, including short-range charge transfer (SRCT), through-bond (TBCT), through-space (TSCT). proof-of-concept emitter 4tCz2B exhibits bright green emission with narrow full width at half maximum (FWHM) 21 nm (0.10 eV) in solution, photoluminescence quantum yield 97%, fast kRISC 7.8 × 105 s-1 significantly film state. As result, sensitizer-free organic light-emitting diodes (OLEDs) achieve external efficiencies (EQEmaxS) over 34.5% together unaltered peak 508 FWHM 26 doping concentrations ranging from 3 20 wt.%. Even ratio 50 wt.%, EQEmax still as 25.5%. More importantly, non-sensitized devices exhibit reduced efficiency roll-offs, minimum value 13.4% brightness 1000 cd m-2.

Язык: Английский

---

Recent Progress in Molecular Design of Boron/Nitrogen‐Based Multi‐Resonance Materials for Narrowband Organic Light‐Emitting Diodes

Advanced Optical Materials, Год журнала: 2025, Номер unknown

Опубликована: Апрель 11, 2025

Abstract Luminescent boron‐nitrogen (BN)‐type multi‐resonance (MR) materials have been first reported by Hatakeyama and co‐workers in 2016. BN‐type MR attracted a lot of attention, because their unique photophysical properties, including narrowband emissions, high photoluminescent quantum yields, thermally activated delayed fluorescent (TADF) properties. MR‐TADF are considered as the next‐generation luminescent for efficient, stable, narrow‐emission organic light‐emitting diodes (OLEDs). Herein, comprehensive review recent progress is provided highlighting structures, device performances. Moreover, future perspective development will be discussed.

Язык: Английский

---

Engineering emissive excited states in organic electroluminescent materials

Matter, Год журнала: 2025, Номер 8(6), С. 102142 - 102142

Опубликована: Июнь 1, 2025

Язык: Английский

---

Recent Progress in High-Performance Thermally Activated Delayed Fluorescence Exciplexes Based on Multiple Reverse Intersystem Crossing Channels

Organic Electronics, Год журнала: 2024, Номер 136, С. 107159 - 107159

Опубликована: Ноя. 5, 2024

Язык: Английский

---

Governing hybridized local and Charge-Transfer state in B,N-Embedded emitters for OLEDs

Chemical Engineering Journal, Год журнала: 2024, Номер unknown, С. 158909 - 158909

Опубликована: Дек. 1, 2024

Язык: Английский

---