Steric Rooted Multi‐Resonant Thermally Activated Delayed Fluorescent Emitters for Pure Blue Organic Light Emitting Diodes with Ultralow Efficiency Roll‐Off DOI
Ezhakudiyan Ravindran,

Ho Eon Baek,

Hee Won Son

et al.

Advanced Functional Materials, Journal Year: 2023, Volume and Issue: 33(35)

Published: May 14, 2023

Abstract Multi‐resonant thermally activated delayed fluorescent ( MR‐TADF ) materials are blooming for high‐resolution organic light‐emitting diodes (OLEDs). However, boron/nitrogen (B/N)‐integrated emitters suffer severe efficiency roll‐off from their strong inter‐molecular π – interactions. Herein, versatile narrowband pure blue mono‐ mx ‐CzDABNA and tri‐ demonstrated featuring a ring‐fused extended ‐skeleton: classic steric hindrance rigidity accessed by integrating with meta ‐xylene rotors. shows (FWHM, 26 nm) emission λ max , 462 substantial hypsochromic shift (12 while maintaining characteristics. The key solid‐state analyses conclude that they conceivably suppress the non‐radiative energy loss, thus improving photoluminescence quantum yield (PLQY > 90%) rate of reverse intersystem crossing (RISC) k RISC ≈2.85 × 10 5 s −1 ). integration tri meta‐xylene significantly leads to an enhanced horizontal dipole ratio (HDR) 65% 85%. Hyperfluorescent‐OLEDs fabricated using designed as terminal emitter, achieving 34 electroluminescence 472 maximum external (EQE 26.97% magnificently suppressed (7.8%) at 1000 cd m −2 . So, it is believed regulation internal efficiencies high color purity can amplify route through new synthetic approaches.

Language: Английский

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

Advanced Optical Materials, Journal Year: 2022, Volume and Issue: 10(22)

Published: Sept. 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.

Language: Английский

Citations

293
Organoboron-based multiple-resonance emitters: synthesis, structure–property correlations, and prospects DOI Creative Commons
Masashi Mamada, Masahiro Hayakawa, Junki Ochi

et al.

Chemical Society Reviews, Journal Year: 2024, Volume and Issue: 53(3), P. 1624 - 1692

Published: Jan. 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.

Language: Английский

Citations

117
Dense Local Triplet States and Steric Shielding of a Multi‐Resonance TADF Emitter Enable High‐Performance Deep‐Blue OLEDs DOI

Hyung‐Jin Cheon,

Seung‐Je Woo,

Seung‐Hyun Baek

et al.

Advanced Materials, Journal Year: 2022, Volume and Issue: 34(50)

Published: Oct. 12, 2022

Multi-resonance thermally activated delayed fluorescence (MR-TADF) molecules based on boron and nitrogen atoms are emerging as next-generation blue emitters for organic light-emitting diodes (OLEDs) due to their narrow emission spectra triplet harvesting properties. However, intermolecular aggregation stemming from the planar structure of typical MR-TADF that leads concentration quenching broadened limits utilization full potential emitters. Herein, a deep-blue emitter, pBP-DABNA-Me, is developed suppress interactions effectively. Furthermore, photophysical investigation theoretical calculations reveal adding biphenyl moieties core body creates dense local states in vicinity S1 T1 energetically, letting emitter harvest excitons efficiently. OLEDs pBP-DABNA-Me show high external quantum efficiency (EQE) 23.4% pure-blue with Commission Internationale de L'Eclairage (CIE) coordinate (0.132, 0.092), which maintained even at doping 100 wt%. by incorporating conventional TADF sensitizer, CIE value (0.133, 0.109) an extremely EQE 30.1% realized. These findings provide insight into design strategies developing efficient fast upconversion suppressed self-aggregation.

Language: Английский

Citations

92
Boron‐Based Narrowband Multiresonance Delayed Fluorescent Emitters for Organic Light‐Emitting Diodes DOI Creative Commons
Rajendra Kumar Konidena, Kenkera Rayappa Naveen

Advanced Photonics Research, Journal Year: 2022, Volume and Issue: 3(11)

Published: Sept. 4, 2022

Recently, the exploration of boron (B)/heteroatom‐embedded polycyclic nanographites featuring multiresonance thermally activated delayed fluorescence (MR‐TADF) garners astonishing attention to promote advancement organic light‐emitting diodes (OLEDs). Contrary traditional donor–acceptor (D–A)‐type TADF emitters, MR‐TADF emitters manifest narrowband emission with full width at half maximum (FWHM ≤ 40 nm) and superior photoluminescence quantum yield (PLQY) coupled small singlet–triplet energy splitting, which appeal their potential as promising candidates in fabricating efficient OLEDs. Growingly, deliver benchmark device performance comparable conventional TADF/phosphorescent emitters. However, they are suffering from major drawbacks such difficult realize full‐color slow exciton upconversion dynamics, aggregation‐caused quenching, severe efficiency roll‐off, poor operational lifetime, jeopardizes practical applicability. Herein, a comprehensive review on B‐based reported till date is presented, focusing different design strategies documented for circumventing aforementioned shortcomings. This divided into several subgroups based color materials draw electronics community toward constructing MR‐OLEDs. Finally, challenges opportunities discussed.

Language: Английский

Citations

73
Triptycene‐Fused Sterically Shielded Multi‐Resonance TADF Emitter Enables High‐Efficiency Deep Blue OLEDs with Reduced Dexter Energy Transfer DOI
Hanif Mubarok, Al Amin, Taehwan Lee

et al.

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(32)

Published: June 16, 2023

Designing multi-resonance (MR) emitters that can simultaneously achieve narrowband emission and suppressed intermolecular interactions is challenging for realizing high color purity stable blue organic light-emitting diodes (OLEDs). Herein, a sterically shielded yet extremely rigid emitter based on triptycene-fused B,N core (Tp-DABNA) proposed to address the issue. Tp-DABNA exhibits intense deep emissions with narrow full width at half maximum (FWHM) horizontal transition dipole ratio, superior well-known bulky emitter, t-DABNA. The MR skeleton of suppresses structural relaxation in excited state, reduced contributions from medium- high-frequency vibrational modes spectral broadening. hyperfluorescence (HF) film composed sensitizer shows Dexter energy transfer compared those t-DABNA DABNA-1. Notably, TADF-OLEDs display higher external quantum efficiencies (EQEmax =24.8 %) narrower FWHMs (≤26 nm) than t-DABNA-based OLEDs =19.8 %). HF-OLEDs further demonstrate improved performance an EQEmax 28.7 % mitigated efficiency roll-offs.

Language: Английский

Citations

53
Suppression of Dexter transfer by covalent encapsulation for efficient matrix-free narrowband deep blue hyperfluorescent OLEDs DOI Creative Commons
Hwan‐Hee Cho, Daniel G. Congrave, Alexander J. Gillett

et al.

Nature Materials, Journal Year: 2024, Volume and Issue: 23(4), P. 519 - 526

Published: March 13, 2024

Abstract Hyperfluorescence shows great promise for the next generation of commercially feasible blue organic light-emitting diodes, which eliminating Dexter transfer to terminal emitter triplet states is key efficiency and stability. Current devices rely on high-gap matrices prevent transfer, unfortunately leads overly complex from a fabrication standpoint. Here we introduce molecular design where ultranarrowband emitters are covalently encapsulated by insulating alkylene straps. Organic diodes with simple emissive layers consisting pristine thermally activated delayed fluorescence hosts doped exhibit negligible external quantum drops compared non-doped devices, enabling maximum 21.5%. To explain high in absence matrices, turn transient absorption spectroscopy. It directly observed that sensitizer host can be substantially reduced an emitter, opening door highly efficient ‘matrix-free’ hyperfluorescence.

Language: Английский

Citations

35
B‒N covalent bond-involved π-extension of multiple resonance emitters enables high-performance narrowband electroluminescence DOI Creative Commons
Xingyu Huang, Jiahui Liu,

Yulin Xu

et al.

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

Citations

21
The Golden Age of Thermally Activated Delayed Fluorescence Materials: Design and Exploitation DOI Creative Commons
John Marques dos Santos, David Hall, Biju Basumatary

et al.

Chemical Reviews, Journal Year: 2024, Volume and Issue: unknown

Published: Dec. 12, 2024

Since the seminal report by Adachi and co-workers in 2012, there has been a veritable explosion of interest design thermally activated delayed fluorescence (TADF) compounds, particularly as emitters for organic light-emitting diodes (OLEDs). With rapid advancements innovation materials design, efficiencies TADF OLEDs each primary color points well white devices now rival those state-of-the-art phosphorescent emitters. Beyond electroluminescent devices, compounds have also found increasing utility applications numerous related fields, from photocatalysis, to sensing, imaging beyond. Following our previous review 2017 (

Language: Английский

Citations

21
Manipulating Spectral Width and Emission Wavelength towards Highly Efficient Blue Asymmetric Carbazole Fused Multi-Resonance Emitters DOI
Hyuna Lee, Ramanaskanda Braveenth,

Jae Do Park

et al.

ACS Applied Materials & Interfaces, Journal Year: 2022, Volume and Issue: 14(32), P. 36927 - 36935

Published: Aug. 3, 2022

The novel carbazole-based multiresonance types of thermally activated delayed fluorescence (MR-TADF) emitters mICz-DABNA and BFCz-DABNA are reported, their spectroscopic properties investigated with the inductive effect on central nitrogen atom for pure deep blue emission. With introduction electron-donating/-withdrawing substituents, exhibited bathochromic/hypsochromic shifted emission, respectively, compared to simple MR-TADF. Moreover, spectral bandwidths became narrower. Theoretical calculation indicated that meta-positioned bulky moiety restricts molecular geometry discrepancy reduces Huang-Rhys factors. Particularly, organic light-emitting diode (OLED) 3% maximum external quantum efficiency 28.0% Commission International de l'Éclairage (CIE) (0.13, 0.09), which is best record value among single-boron MR-TADF devices CIE y < 0.10.

Language: Английский

Citations

42
Toward highly efficient deep-blue OLEDs: Tailoring the multiresonance-induced TADF molecules for suppressed excimer formation and near-unity horizontal dipole ratio DOI Creative Commons
Hyung Suk Kim, Hyung Jin Cheon, Donggyun Lee

et al.

Science Advances, Journal Year: 2023, Volume and Issue: 9(22)

Published: May 31, 2023

Boron-based compounds exhibiting a multiresonance thermally activated delayed fluorescence are regarded promising as narrowband blue emitter desired for efficient displays with wide color gamut. However, their planar nature makes them prone to concentration-induced excimer formation that broadens the emission spectrum, making it hard increase concentration without raising CIE y coordinate. To overcome this bottleneck, we here propose o-Tol-ν-DABNA-Me, wherein sterically hindered peripheral phenyl groups introduced reduce intermolecular interactions, leading and thus pure character far less sensitive concentration. With approach, demonstrate deep-blue OLEDs of 0.12 full width at half maximum 18 nm, external quantum efficiency (EQE) ca. 33%. Adopting hyperfluorescent architecture, OLED performance is further enhanced EQE 35.4%, mitigated roll-off, illustrating immense potential proposed method energy-efficient OLEDs.

Language: Английский

Citations

37