Deep‐Blue Narrowband Hetero[6]helicenes Showing Circularly Polarized Thermally Activated Delayed Fluorescence Toward High‐Performance OLEDs

Advanced Materials, Journal Year: 2023, Volume and Issue: 36(1)

Published: Nov. 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.

Language: Английский

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Helical Synthetic Nanographenes with Atomic Precision

Accounts of Chemical Research, Journal Year: 2023, Volume and Issue: 56(3), P. 363 - 373

Published: Jan. 26, 2023

ConspectusUnderstanding and harnessing the properties of nanoscale molecular entities are considered as new frontiers in basic chemistry. In this regard, synthetic nanographene with atomic precision has attracted much attention recently. For instance, taking advantage marvelous bonding capability carbon, flat, curved, ribbon-type, or cone-shaped nanographenes have been prepared highly controllable elegant manner, allowing one to explore fascinating architectures intriguing optical, electrochemical, magnetic characteristics. This stands stark contrast other carbon-rich nanomaterials, such graphite oxides carbon quantum dots, which preclude thorough investigations because complicate structural defects. Undoubtedly, contributes strongly modern aromatic chemistry represents a vibrant field that may deliver transforming functional materials crucial for optoelectronics, nanotechnologies, biomedicine.Nonetheless, many cases, synthesis characterization compounds demanding. Low solubility, high strain, undesired selectivity, well incomplete excessive C-C bond formation common impediments, require formidable efforts control geometry, modulate edge structure, achieve accurate doping, push upper size boundary. These endeavors indispensable establishing structure-property relationships, lay down foundation exploring at level sophistications.In Account, we summarize our contributions by presenting series helical nanographenes, hexapole [7]helicene (H7H), nitrogen-doped H7H, [9]helicene (H9H), superhelicene, supertwistacene. kind giant reaches domain albeit precise structure. It provides unique platform study chirality nanoscale. We discuss methods point out, particular, strengths pitfalls Scholl oxidation, expected be valuable making general. addition, illustrate their exciting electrochemical photophysical performance, include, but not limited to, reversible multielectron redox chemistry, record panchromatic absorption, impressive photothermal behavior, extremely strong Cotton effect. unusual characteristics convincingly traced back three-dimensional conjugated architectures, highlighting critical roles π-electron delocalization, heteroatom-doping, substitution, symmetry determining nanographenes' functions. Lastly, put forward understanding on challenges opportunities lies ahead hope Account will inspire ever more ambitious achievements from attractive area research.

Language: Английский

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Synthesis of a π‐Extended Double [9]Helicene

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(18)

Published: March 2, 2023

Double helicenes are appealing chiral frameworks. Their π-extension is desirable to achieve (chir)optical response in the visible and near-infrared (NIR) region, but access higher double [n]helicenes (n≥8) has remained challenging. Herein, we report an unprecedented π-extended [9]helicene (D9H), unambiguously revealing its structure by single-crystal X-ray diffraction. D9H shows remarkable NIR emission from 750 1100 nm with a high photoluminescence quantum yield of 18 %. In addition, optically pure exhibits panchromatic circular dichroism notable dissymmetry factor (gCD ) 0.019 at 590 nm, which among highest region for reported helicenes.

Language: Английский

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Red Emissive Double Aza[7]helicenes with Antiaromaticity / Aromaticity Switching via the Redox‐Induced Radical Cation and Dication Species

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(18)

Published: March 6, 2023

We herein present the synthetic approach to a new antiaromatic double aza[7]helicene C that features NN-embedded polycyclic aromatic hydrocarbons (PAHs). This heteroatom-doped helicene showed rarely obtained long-wavelength emission and far-red circularly polarized luminescence (CPL) in solid state. These optical chiroptical properties could be ascribed both NN-PAH core structure further extension through angular ring fusions. Such unique electronic also culminated facile chemical oxidations of neutral positively charged chiral radical (C⋅+ ) dication species (C2+ ). Interestingly, DFT computations revealed pyridazine central an antiaromaticity-to-aromaticity switching, contrast inversed transition for helical periphery cationic states. The reported approaches are anticipated lead development redox-active systems potential applications chiroptoelectronics, spintronics as well fluorescent bioimaging.

Language: Английский

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Macrocyclic Engineering of Thermally Activated Delayed Fluorescent Emitters for High‐Efficiency Organic Light‐Emitting Diodes

Advanced Materials, Journal Year: 2023, Volume and Issue: 35(39)

Published: May 13, 2023

Several thermally activated delayed fluorescence (TADF) materials have been studied and developed to realize high-performance organic light-emitting diodes (OLEDs). However, TADF macrocycles not sufficiently investigated owing the synthetic challenges, resulting in limited exploration of their luminescent properties corresponding highly efficient OLEDs. In this study, a series is synthesized using modularly tunable strategy by introducing xanthones as acceptors phenylamine derivatives donors. A detailed analysis photophysical combined with fragment molecules reveals characteristics macrocycles. The results indicate that: a) ideal structure decreases energy loss, which turn reduces non-radiative transitions; b) reasonable building blocks increase oscillator strength providing higher radiation transition rate; c) horizontal dipole orientation (Θ) extended macrocyclic emitters increased. Owing high photoluminescence quantum yields ≈100% 92% excellent Θ 80 79% for MC-X MC-XT 5 wt% doped films, devices exhibit record-high external efficiencies 31.6% 26.9%, respectively, field

Language: Английский

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π-Extended Helical Multilayer Nanographenes with Layer-Dependent Chiroptical Properties

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(49), P. 26824 - 26832

Published: Dec. 4, 2023

Helical nanographenes (NGs) have attracted increasing attention recently because of their intrinsic chirality and exotic chiroptical properties. However, the efficient synthesis extended helical NGs featuring a multilayer topology is still underdeveloped, layer-dependent properties remain elusive. In this study, we demonstrate modular synthetic strategy to construct series novel (1-3) with through consecutive Diels-Alder reaction regioselective cyclodehydrogenation from readily accessible phenanthrene-based precursors bearing ethynyl groups. The resultant exhibit bilayer, trilayer, tetralayer structures elongated π extension rigid backbones, as unambiguously confirmed by single-crystal X-ray or electron diffraction analysis. We find that photophysical these are notably influenced degree extension, which varies number layers, leading obvious redshifted absorption, fast rising molar extinction coefficient (ε), markedly boosted fluorescence quantum yield (Φf). Moreover, embedded [7]helicene subunits in result stable chirality, enabling both chiral resolution exploration Profiting good alignment electric magnetic dipole moments determined structure, excellent circular dichroism circularly polarized luminescence response unprecedented high CPL brightness up 168 M-1 cm-1, rendering them promising candidates for emitters.

Language: Английский

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Emergent induced circularly polarized luminescence in host–guest crystalline porous assemblies

Coordination Chemistry Reviews, Journal Year: 2024, Volume and Issue: 514, P. 215859 - 215859

Published: May 9, 2024

Language: Английский

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Enhancing Chiroptical Responses in Helical Nanographenes via Geometric Engineering of Double [7]Helicenes

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(19)

Published: Feb. 19, 2024

Helical nanographenes with high quantum yields and strong chiroptical responses are pivotal for developing circularly polarized luminescence (CPL) materials. Here, we present the successful synthesis of novel π-extended double [7]helicenes (ED7Hs) where two helicene units fused at meta- or para-position middle benzene ring, respectively, as structural isomers reported ortho-fused ED7H. The geometry these ED7Hs is clearly characterized by single-crystal X-ray analysis. Notably, this class exhibits bright exceeding 40 %. Through geometric regulation embedded [7]helicene from ortho-, to para-position, display exceptional amplification in responses. This enhancement evident a remarkable approximate fivefold increase absorbance dissymmetry factors (g

Language: Английский

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A Double Twisted Nanographene with a Contorted Pyrene Core

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(35)

Published: June 21, 2024

The mature synthetic methodologies enable us to rationally design and produce chiral nanographenes (NGs), most of which consist multiple helical motifs. However, inherent chirality originating from twisted geometry has just emerged be employed in NGs. Herein, we report a red-emissive NG constituted orthogonally arranged two-fold π-skeletons at contorted pyrene core contributes optical transitions S

Language: Английский

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Direct Edge Functionalization of Corannulene–Coronene Hybrid Nanographenes

JACS Au, Journal Year: 2025, Volume and Issue: unknown

Published: March 24, 2025

For more than a century, electrophilic aromatic substitution reactions have been central to the construction of rich variety organic molecules that are useful in all aspects human life. Typically, small nuclei, such as benzene, provide an ideal substrate. An increase number annulated rings enhances potential reactive sites and frequently results complex product mixtures. Thus, nanographenes with relatively large system seldom selective their positions. Moreover, nanographene substrates scope for multiple patterns remain rare. Herein, we demonstrate curved based on corannulene-coronene hybrid structure comprising 48 conjugated sp 2-carbon atoms allows direct regioselective edge functionalization through bromination, nitration, formylation, Friedel-Crafts acylation good yields. The postsynthetically installed functional groups can be modified versatile chemistry transformations, including (mechanochemical) Suzuki-Miyaura, Sonogashira-Hagihara, Buchwald-Hartwig amination reactions. Furthermore, substitutions carried out sequential manner yield heterofunctional structures. edge-functionalization strategy enables modular access nanostructures appealing properties, strong fluorescence emission visible near-infrared regions (475-900 nm) record Stokes shifts (>300 nm), at exceptionally carbon footprint (C48).

Language: Английский

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