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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B‐N Covalent Bond Embedded Double Hetero‐[n]helicenes for Pure Red Narrowband Circularly Polarized Electroluminescence with High Efficiency and Stability

Advanced Materials, Journal Year: 2023, Volume and Issue: 36(5)

Published: Sept. 12, 2023

Chiral B/N embedded multi-resonance (MR) emitters open a new paradigm of circularly polarized (CP) organic light-emitting diodes (OLEDs) owing to their unique narrowband spectra. However, pure-red CP-MR and devices remain exclusive in literature. Herein, by introducing B-N covalent bond lower the electron-withdrawing ability para-positioned B-π-B motif, first pair double hetero-[n]helicenes (n = 6 7) emitter peaking 617 nm with small full-width at half-maximum 38 high photoluminescence quantum yield ≈100% toluene is developed. The intense mirror-image CP light produced enantiomers characterized dissymmetry factors (g

Language: Английский

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Tailored Fabrication of Full‐Color Ultrastable Room‐Temperature Phosphorescence Carbon Dots Composites with Unexpected Thermally Activated Delayed Fluorescence

Advanced Materials, Journal Year: 2024, Volume and Issue: 36(27)

Published: April 23, 2024

Abstract The development of single‐system materials that exhibit both multicolor room‐temperature phosphorescence (RTP) and thermally activated delayed fluorescence (TADF) with tunable after glow colors channels is challenging. In this study, four metal‐free carbon dots (CDs) are developed through structural tailoring, panchromatic high‐brightness RTP achieved via strong chemical encapsulation in urea. maximum lifetime quantum yield reaches 2141 ms 56.55%, respectively. Moreover, CDs‐IV@urea, prepared coreshell interaction engineering, exhibits a dual afterglow red green TADF. degree conjugation functional groups precursors affects the binding interactions nitrogen cladding on CDs, which turn stabilizes triplet energy levels gap between S 1 T (Δ E ST ) to induce RTP. enhanced wrapping lowers Δ , promoting reverse intersystem crossing, leads This fully state, thus stabilizing material water, even extreme environments such as acids oxidants. These tested multicolor, time, temperature multiencryption well vivo bioimaging. Hence, these have promising practical applications information security biomedical diagnosis treatment.

Language: Английский

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B,N‐Embedded Hetero[9]helicene Toward Highly Efficient Circularly Polarized Electroluminescence

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(18)

Published: Feb. 21, 2024

The intrinsic helical π-conjugated skeleton makes helicenes highly promising for circularly polarized electroluminescence (CPEL). Generally, carbon undergo low external quantum efficiency (EQE), while the incorporation of a multi-resonance thermally activated delayed fluorescence (MR-TADF) BN structure has led to an improvement. However, reported B,N-embedded all show dissymmetry factors (g

Language: Английский

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B‒N covalent bond-involved π-extension of multiple resonance emitters enables high-performance narrowband electroluminescence

National Science Review, Journal Year: 2024, Volume and Issue: 11(6)

Published: March 23, 2024

ABSTRACT Multi-boron-embedded multiple resonance thermally activated delayed fluorescence (MR-TADF) emitters show promise for achieving both high color-purity emission and exciton utilization efficiency. However, their development is often impeded by a limited synthetic scope excessive molecular weights, which challenge material acquisition organic light-emitting diode (OLED) fabrication vacuum deposition. Herein, we put forward B‒N covalent bond-involved π-extension strategy via post-functionalization of MR frameworks, leading to the generation high-order B/N-based motifs. The structurally electronically extended π-system not only enhances rigidity narrow linewidth but also promotes reverse intersystem crossing mitigate efficiency roll-off. As illustrated examples, ultra-narrowband sky-blue (full-width at half-maximum as small 8 nm in n-hexane) have been developed with multi-dimensional improvement photophysical properties compared precursor emitters, enables narrowband OLEDs external quantum efficiencies (EQEmax) up 42.6%, company alleviated decline brightness, representing best reported single-host OLEDs. success these highlights effectiveness our design advanced MR-TADF confirms extensive potential high-performance optoelectronic devices.

Language: Английский

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Tetraborated Intrinsically Axial Chiral Multi‐resonance Thermally Activated Delayed Fluorescence Materials

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(32)

Published: May 23, 2024

Abstract Chiral multi‐resonance thermally activated delayed fluorescence (CP‐MR‐TADF) materials hold promise for circularly polarized organic light‐emitting diodes (CP‐OLEDs) and 3D displays. Herein, we present two pairs of tetraborated intrinsically axial CP‐MR‐TADF materials, R/S ‐ BDBF‐BOH BDBT‐BOH , with conjugation‐extended bidibenzo[ b,d ]furan ]thiophene as chiral sources, which effectively participate in the distribution frontier molecular orbitals. Due to heavy‐atom effect, sulfur atoms are introduced accelerate reverse intersystem crossing process increase efficiency molecules. manifest ultra‐pure blue emission a maximum at 458/459 nm full width half 27 nm, photoluminescence quantum yields 90 %/91 %, dissymmetry factors (| g PL |) 6.8×10 −4 /8.5×10 respectively. Correspondingly, CP‐OLEDs exhibit good performances an external 30.1 % | EL 1.2×10 −3 .

Language: Английский

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Boron-containing helicenes as new generation of chiral materials: opportunities and challenges of leaving the flatland

Chemical Science, Journal Year: 2024, Volume and Issue: 15(20), P. 7408 - 7440

Published: Jan. 1, 2024

Recent advances in synthesis have opened the way to a variety of boron helicenes. We highlight main achievements these chiral compounds and discuss their photophysical properties potential as functional materials.

Language: Английский

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Frontier Molecular Orbital Engineering: Constructing Highly Efficient Narrowband Organic Electroluminescent Materials

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(52)

Published: Sept. 19, 2023

Abstract It is of great strategic significance to develop highly efficient narrowband organic electroluminescent materials that can be utilized manufacture ultra‐high‐definition (UHD) displays and meet or approach the requirements Broadcast Television 2020 (B.T.2020) color gamut standards. This motif poses challenges for molecular design synthesis, especially developing generality, diversity, scalability, robustness structures. The emergence multiple resonance thermally activated delayed fluorescence (MR‐TADF) emitters has ingeniously solved problems demonstrated bright application prospects in field UHD displays, sparking a research boom. Minireview summarizes endeavors materials, with emphasis on tremendous contribution frontier orbital engineering (FMOE) strategy. combines outstanding advantages MR framework donor‐acceptor (D−A) structure, achieve red‐shift emission simultaneously, which development long‐wavelength maxima exceeding 500 nm. We hope this would provide some inspiration what could transpire future.

Language: Английский

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Concentration‐Switchable Assembly of Carbon Dots for Circularly Polarized Luminescent Amplification in Chiral Logic Gates and Deep‐Red Light‐Emitting Diodes

Advanced Materials, Journal Year: 2024, Volume and Issue: unknown

Published: Oct. 3, 2024

Abstract Stimuli‐responsive circularly polarized luminescent (CPL) materials are expected to find widespread application in advanced information technologies, such as 3D displays, multilevel encryption, and chiral optical devices. Here, using R‐/S‐α‐phenylethylamine 3,4,9,10‐perylenetetracarboxylic dianhydride precursors, carbon dots (Ch‐CDs) exhibiting bright concentration‐dependent luminescence synthesized, demonstrating reversible responses both their morphologies emission spectra. By adjusting Ch‐CD concentration, the switchable wavelength is extended over 180 nm (539–720 nm), with maximum quantum efficiency reaching 100%. Meanwhile, upon increasing red‐shifts, while chirality of assembled nanoribbons synchronously amplified, ultimately achieving CPL at 709 a asymmetry factor 2.18 × 10 −2 . These values represent longest largest g lum reported for CDs. Considering remarkable properties synthesized Ch‐CDs, logic gates designed, potential practical applications demonstrated anti‐counterfeiting flexible electronic printing, solid‐state CPL. Furthermore, deep‐red electroluminescence light‐emitting diodes (EL‐LEDs) prepared these an external 1.98%, which highest value date CDs EL‐LEDs, first report devices based on

Language: Английский

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Chiral multiple-resonance thermally activated delayed fluorescence materials based on chiral spiro-axis skeleton for efficient circularly polarized electroluminescence

Science China Chemistry, Journal Year: 2024, Volume and Issue: 67(7), P. 2257 - 2264

Published: June 11, 2024

Language: Английский

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