Deep‐Blue Narrowband Hetero[6]helicenes Showing Circularly Polarized Thermally Activated Delayed Fluorescence Toward High‐Performance OLEDs DOI
Zeyuan Ye, Han Wu,

Yulin Xu

и другие.

Advanced Materials, Год журнала: 2023, Номер 36(1)

Опубликована: Ноя. 14, 2023

Abstract Helicenes exhibit substantial potential as circularly polarized luminescence (CPL) active molecules. However, their application in organic light‐emitting diodes (CP‐OLEDs) is typically hindered by the challenge of integrating both high color purity and efficient triplet‐harvesting capability, particularly blue spectral region. Herein, a series hetero[6]helicene‐based emitters that strategically engineered through helical extension deep‐blue double‐boron‐based multiple resonance thermally activated delayed fluorescence (MR‐TADF) motif, introduced. Importantly, does not cause apparent structural deformation or perturb frontier molecular orbitals; thus, preserving emission MR‐TADF characteristics parent molecule. This approach also leads to reduced reorganization energy, resulting with narrower linewidth higher photoluminescence quantum yield. Further, motif enhances racemization barrier improved CPL performance dissymmetry factor values up 1.5 × 10 −3 . Exploiting these merits, devices incorporating chiral dopants demonstrate within Broadcast Service Television 2020 color‐gamut range, record external efficiencies (EQEs) 29.3%, have distinctive electroluminescence (CPEL) signals. Overall, authors’ findings underscore promising strategy for designing narrowband chiroptical materials advancing high‐definition displays.

Язык: Английский

Narrowband Emissive Thermally Activated Delayed Fluorescence Materials DOI Creative Commons
Hyung Jong Kim, Takuma Yasuda

Advanced Optical Materials, Год журнала: 2022, Номер 10(22)

Опубликована: Сен. 23, 2022

Abstract Organic thermally activated delayed fluorescence (TADF) materials have attracted significant research interest in the field of organic electronics because their inherent advantage 100% exciton utilization capability light‐emitting diodes (OLEDs) without use noble metals. However, despite high internal electroluminescence quantum efficiencies approaching unity, broad emission spectra with sizable full width at half maxima (FWHM; 60–100 nm) present a critical issue that must be solved for application ultrahigh‐definition OLED displays. Recently, new paradigm TADF featuring multiple resonance (MR) effect based on heteroatom‐doped polycyclic aromatic frameworks, referred to as MR‐TADF materials, has emerged and garnered considerable owing remarkable features efficient narrowband emissions extremely small FWHMs (≤30 nm). Currently, occupy prominent position cutting‐edge from both chemical physical perspectives. This review article focuses recent progress emissive systems perspective molecular design, photophysical properties, performance OLEDs. The current status future prospects this advanced material technology are discussed comprehensively.

Язык: Английский

Процитировано

306
Extending the π‐Skeleton of Multi‐Resonance TADF Materials towards High‐Efficiency Narrowband Deep‐Blue Emission DOI
Xialei Lv, Jingsheng Miao, Meihui Liu

и другие.

Angewandte Chemie International Edition, Год журнала: 2022, Номер 61(29)

Опубликована: Май 10, 2022

Multi-resonance TADF (MR-TADF) emitters are promising for high-resolution OLEDs, but the concurrent optimization of excited-state dynamics and color purity remains a tough challenge. Herein, three deep-blue MR-TADF compounds (BN1-BN3) featuring gradually enlarged ring-fused structures increased rigidity accessed by lithium-free borylation in high yields from same precursor, with all possessing CIEy coordinates below 0.08. Structure-property investigations demonstrate strategic improvement oscillator strength (fosc ) acceleration reverse intersystem crossing (RISC) process extending π-skeleton, where BN3 realizes maximum external quantum efficiency (EQE) 37.6 % reduced roll-off, thus showing best reported OLEDs. The internal regulation these validate general effectiveness to achieve advanced narrowband higher-order boron/nitrogen-based MR motifs.

Язык: Английский

Процитировано

187
Ultrafast Triplet–Singlet Exciton Interconversion in Narrowband Blue Organoboron Emitters Doped with Heavy Chalcogens DOI
In Seob Park,

Hyukgi Min,

Takuma Yasuda

и другие.

Angewandte Chemie International Edition, Год журнала: 2022, Номер 61(31)

Опубликована: Май 27, 2022

Narrowband emissive organoboron emitters featuring the multi-resonance (MR) effect have now become a critical material component for constructing high-performance organic light-emitting diodes (OLEDs) with pure emission colors. These MR are capable of exhibiting high-efficiency narrowband thermally activated delayed fluorescence (TADF) by allowing triplet-to-singlet reverse intersystem crossing (RISC). However, RISC involving spin-flip exciton upconversion is generally rate-limiting step in overall TADF; hence, deeper understanding and precise control dynamics ongoing crucial challenges. Here, we introduce first emitter (CzBSe) doped selenium atom, demonstrating record-high rate exceeding 108 s-1 , which even higher than its radiation rate. Furthermore, process CzBSe can be accelerated factors ≈20000 ≈800, compared to those oxygen- sulfur-doped homologs (CzBO CzBS), respectively. Unlike CzBO CzBS, photophysical no longer RISC, but process; this behavior completely different from conventional time-delaying TADF limited slow RISC. Benefitting ultrafast spin conversion ability, OLEDs incorporating achieved maximum external electroluminescence quantum efficiency as high 23.9 %, accompanied MR-induced blue significantly alleviated roll-off features.

Язык: Английский

Процитировано

163
Space‐Confined Donor‐Acceptor Strategy Enables Fast Spin‐Flip of Multiple Resonance Emitters for Suppressing Efficiency Roll‐Off DOI
Yang Liu, Xin Xiao,

Zhenmei Huang

и другие.

Angewandte Chemie International Edition, Год журнала: 2022, Номер 61(40)

Опубликована: Авг. 18, 2022

Multi-resonance boron-nitrogen-containing thermally activated delayed fluorescence (MR-TADF) emitters have experienced great success in assembling narrowband organic light-emitting diodes (OLEDs). However, the slow reverse intersystem crossing rate (kRISC ) of MR-emitters (103 -105 s-1 that will lead to severe device efficiency roll-off has received extensive attention and remains a challenging issue. Herein, we put forward "space-confined donor-acceptor (SCDA)" strategy accelerate RISC process. The introduction SCDA units onto MR-skeleton induces intermediate triplet states, which leads multichannel process thus increases kRISC . As illustrated examples, efficient been developed with sub-microsecond lifetime high 2.13×106 , enables assemble high-performance OLEDs maximum external quantum (EQEmax as 32.5 % an alleviated (EQE1000 : 22.9 %).

Язык: Английский

Процитировано

127
Organoboron-based multiple-resonance emitters: synthesis, structure–property correlations, and prospects DOI Creative Commons
Masashi Mamada, Masahiro Hayakawa, Junki Ochi

и другие.

Chemical Society Reviews, Год журнала: 2024, Номер 53(3), С. 1624 - 1692

Опубликована: Янв. 1, 2024

This review highlights organoboron-based multiple-resonance compounds’ synthetic strategies classified as one-pot borylation, one-shot and late-stage functionalisation, explores material structure–photophysical property correlations.

Язык: Английский

Процитировано

126
Charge Transfer Excited State Promoted Multiple Resonance Delayed Fluorescence Emitter for High-Performance Narrowband Electroluminescence DOI
Zhongyan Huang,

Honghui Xie,

Jingsheng Miao

и другие.

Journal of the American Chemical Society, Год журнала: 2023, Номер 145(23), С. 12550 - 12560

Опубликована: Июнь 5, 2023

Multiple resonance thermally activated delayed fluorescence (MR-TADF) emitters are promising candidates for narrowband organic light-emitting diodes, but their electroluminescent performance is typically hindered by the slow reverse intersystem crossing rate (kRISC). Herein, we present an effective strategy to introduce a multichannel (RISC) pathway with large spin-orbit coupling orthogonally linking electron-donating unit MR framework. Through delicate manipulation of excited-state energy levels, additional intersegmental charge transfer triplet state could be "silently" induced without perturbing character lowest excited singlet state. The proof-of-concept emitter CzBN3 not only affords 23-fold increase kRISC compared its prototypical skeleton also realizes close-to-unity photoluminescence quantum yield, radiative constant, and very narrow emission spectrum. These merits enable high maximum external efficiency (EQEmax) up 37.1% alleviated roll-off in sensitizer-free device (EQE1000 = 30.4%), further boost (EQEmax/1000 42.3/34.1%) realized hyperfluorescent device. state-of-the-art validates superiority our molecular design strategy.

Язык: Английский

Процитировано

123
Chiral Multi‐Resonance TADF Emitters Exhibiting Narrowband Circularly Polarized Electroluminescence with an EQE of 37.2 % DOI

Yiyu Yang,

Nengquan Li, Jingsheng Miao

и другие.

Angewandte Chemie International Edition, Год журнала: 2022, Номер 61(30)

Опубликована: Май 10, 2022

Highly efficient circularly polarized luminescence (CPL) emitters with narrowband emission remain a formidable challenge for OLEDs (CP-OLEDs). Here, promising strategy developing chiral concurrently featuring multi-resonance thermally activated delayed fluorescence (MR-TADF) and electroluminescence (CPEL) is demonstrated by the integration of molecular rigidity, central chirality MR effect. A pair green denoted as (R)-BN-MeIAc (S)-BN-MeIAc designed. Benefited rigid quasi-planar MR-framework, enantiomers not only display mirror-image CPL spectra, but also exhibit TADF properties high photoluminescence quantum yield 96 %, narrow FWHM 30 nm, horizontal dipole orientation 90 % in doped film. Consequently, enantiomer-based CP-OLEDs achieved excellent external efficiencies 37.2 very low efficiency roll-off, representing highest device all reported CP-OLEDs.

Язык: Английский

Процитировано

121
Development of Pure Green Thermally Activated Delayed Fluorescence Material by Cyano Substitution DOI
Susumu Oda,

Takumi Sugitani,

Hiroyuki Tanaka

и другие.

Advanced Materials, Год журнала: 2022, Номер 34(32)

Опубликована: Июнь 21, 2022

Multiple resonance (MR)-effect-induced thermally activated delayed fluorescence (TADF) materials have garnered significant attention because they can achieve both high color purity and external quantum efficiency (EQE). However, the reported green-emitting MR-TADF exhibit broader emission compared to those of blue-emitting ones suffer from severe roll-off due insufficient rate constants reverse intersystem crossing process (kRISC ). Herein, a pure green material (ν-DABNA-CN-Me) with kRISC 105 s-1 is reported. The key success introduction cyano groups into (ν-DABNA), which causes remarkable bathochromic shift without loss purity. organic light-emitting diode employing it as an emitter exhibits at 504 nm small full-width half-maximum 23 nm, corresponding Commission Internationale d'Éclairage coordinates (0.13, 0.65). device achieves maximum EQE 31.9% successfully suppresses luminance.

Язык: Английский

Процитировано

115
Sequential Multiple Borylation Toward an Ultrapure Green Thermally Activated Delayed Fluorescence Material DOI

Shigetada Uemura,

Susumu Oda, Masahiro Hayakawa

и другие.

Journal of the American Chemical Society, Год журнала: 2022, Номер 145(3), С. 1505 - 1511

Опубликована: Дек. 22, 2022

Multiple-resonance thermally activated delayed fluorescence (MR-TADF) emitters have emerged as an important component of organic light-emitting diodes (OLEDs) because their narrowband emission and high exciton utilization efficiency. However, the chemical space MR-TADF remains mostly unexplored lack suitable synthetic protocols. Herein, we demonstrate a sequential multiple borylation reaction that provides new synthetically accessible space. ω-DABNA, proof-of-concept material, exhibited green TADF with full width at half-maximum 22 nm small singlet-triplet energy gap 13 meV. The OLED employing it emitter electroluminescence 512 nm, Commission International de l'Éclairage coordinates (0.13, 0.73) external quantum efficiency (EQE) 31.1%. Moreover, device showed minimum roll-off, EQE 29.4% 1000 cd m-2.

Язык: Английский

Процитировано

110
A Highly Twisted Carbazole‐Fused DABNA Derivative as an Orange‐Red TADF Emitter for OLEDs with Nearly 40 % EQE DOI Open Access

Ying‐Chun Cheng,

Xiao‐Chun Fan, Feng Huang

и другие.

Angewandte Chemie International Edition, Год журнала: 2022, Номер 61(47)

Опубликована: Сен. 28, 2022

Multiple resonance (MR) type thermally activated delayed fluorescence (TADF) material is currently a research hotspot in organic light-emitting diodes (OLEDs) due to their high color purity and exciton utilization. However, there are only handful of MR-TADF emitters with emissions beyond the blue-to-green region. The very limited emission colors for mainly caused by fact that so far molecular modifications do not offer much change colors. Here, we report new approach modifying prototypical MR core DABNA fusing carbazoles framework. carbazole-fused molecule (TCZ-F-DABNA) basically maintains MR-dominated features while red-shifting emission. Its OLED achieves an external quantum efficiency 39.2 % peak at 588 nm, which record-high OLEDs peaks 560 nm. This work provides significantly tunning emitters.

Язык: Английский

Процитировано

109