23 Jul 15:40
Chem. Commun., 2025, 61,10985-10988
DOI: 10.1039/D5CC02234G, Communication
Mengyan Tian, Xinyue Zhao, Shuai Zhao, Yaning Li, Ruofei Wang, Jun Guo, Pai Liu
TPAF, an AIE phototherapeutic agent, was constructed based on a fluorination strategy to prolong the triplet-excited state lifetime and maximize PDT/PTT efficiency.
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23 Jul 15:31
Chem. Commun., 2025, 61,10731-10746
DOI: 10.1039/D5CC02070K, Feature Article
Jia-Ming Jin, Chengxiang Shi, Wen-Cheng Chen, Yanping Huo
Chemical modifications of a multi-resonance thermally activated delayed fluorescence emitter based on the BNCz framework are reviewed.
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23 Jul 15:27
Chem. Commun., 2025, 61,11766-11769
DOI: 10.1039/D5CC02694F, Communication
Xiong Xiao, Jia-Qi Liang, Jia-Jun Hu, Li Yuan, Jia-Zhen Zhu, Zong-Ju Chen, You Song, Cheng-Hui Li, You-Xuan Zheng
Two orange-red planar chiral thermally activated delayed fluorescence emitters exhibit aggregation-induced emission. Their organic light-emitting diodes and circularly polarized devices show low efficiency roll-offs and high dissymmetry factors.
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17 Jul 10:00
by Guoyun Meng,
Jianping Zhou,
Qi Wang,
Tianyu Huang,
Gang Zhang,
Lian Duan,
Dongdong Zhang
The position isomerism and ring-extension strategies effectively modulate the intramolecular short-range charge transfer characteristics and molecular dipole moments of N/C═O-containing derivatives, achieving narrow bandwidths (17–24 nm) and a broad emission range spanning deep blue to green color. The resulting deep-blue OLED achieved an exceptional EQE of up to 29.6% with a CIEy coordinate of 0.063, satisfying the NTSC color standard.
Abstract
Embedding nitrogen/carbonyl (N/C═O) units into rigid heterocyclic aromatic hydrocarbons creates novel multi-resonant thermally activated delayed fluorescence (MR-TADF) molecules. Nevertheless, the intrinsic short-range charge transfer (SRCT) characteristics of N/C═O derivatives, as exemplified by quinolino[3,2,1-de]acridine-5,9-dione (QAO), result in broad spectral bandwidths, posing challenging for achieving deep blue emission. Herein, a pentagonal cyclization and isomeric expansion strategy aimed is proposed at modulating SRCT characters and molecular symmetry to further narrow spectral bandwidths and regulate excited-state energy levels. By fusing two 8H-indolo[3,2,1-de]acridin-8-one (IAO) skeletons via a central phenyl segment that cyclizes two nitrogen atoms, proof-of-concept emitters with reduced SRCT characteristics and narrow spectral widths are developed. These emitters achieved a wide color tuning range from deep blue (439 nm) to pure green (520 nm) and exhibited narrow spectral bandwidths of 17–24 nm (≈0.11 eV). The corresponding electroluminescence devices demonstrated bright deep-blue, blue, and green emissions with narrow linewidths. Notably, sensitized deep-blue/blue devices incorporating mTIAO and pTIAO emitters achieved exceptional external quantum efficiencies of 29.6% and 34.4%, respectively, representing the most efficient blue-light N/C═O derivatives reported to date. Furthermore, the color index of mTIAO, measured at (0.147, 0.063), aligns perfectly with the blue National Television System Committee standard of (0.15, 0.06).
17 Jul 09:59
by Kun Yao,
Zhentan Wang,
Fanjie Lin,
Simin Wang,
Huilin Huang,
Wenchao Geng,
Ji Liu,
Fei Li,
Yang Li,
Zhenwei Yuan,
Liangyu Hu,
Zhongxing Geng
Four cholesteric liquid crystal systems (CLCs) incorporating achiral dichroic dyes with almost identical helical superstructures and pitches display S
F-dependent CPL properties, offering a facile way for the precise regulation of CPL signals in CLCs media. This versatile approach facilitates similar fluorescence wavelengths and distinct CPL behaviors, thereby prompting dual anti-counterfeiting applications.
Abstract
The regulation of circularly polarized luminescence (CPL) behavior of cholesteric liquid crystals (CLCs) by doping achiral dyes is of great significance for the development of real 3D application materials. However, current design strategies for CLCs materials are primarily focused on tuning helical structure, causing the inadequate investigation of fluorescence order parameters (S
F) of achiral dyes on CPL signal regulation. Here, four achiral dichroic dyes with different S
F values are developed in CLCs media. The CLCs system incorporating the
p-C5PhHBT dye achieves the strongest g
lum value of +0.48/−0.47, attributed to its highest order parameter (S
F = 0.56) in CLCs. Moreover, these four CLCs systems exhibit S
F-dependent CPL properties with almost identical helical superstructures and pitches, highlighting the significant potential of S
F regulation as a strategy for tuning CPL signals. Based on the similar fluorescence wavelengths and distinct CPL behaviors observed in CLCs, a concept for dual anti-counterfeiting applications is further proposed.
12 Jul 20:28
by Yichen Zhou,
Junxiang Huang,
Animesh Ghosh,
Andrew C. Grimsdale,
Saran Long,
Qi Tao,
Gagik G. Gurzadyan
By using steady-state, time-resolved spectroscopies and DFT calculations, the competitive relaxation pathways (excimer formation and charge transfer) of excited states for a nonlinear heteroacene derivative DBP6 in DCM are uncovered. The findings reveal DBP6's potential for ratiometric sensing and optoelectronic applications.
Abstract
The photophysical properties and excited-state dynamics of the nonlinear heteroacene derivative DBP6 (bis-phenylethynyl-substituted dibenzophenanthroline) were systematically investigated through steady-state spectroscopy, time-resolved fluorescence measurements, and density functional theory (DFT) calculations. This study focuses on the competitive relaxation pathways after excitation to the lowest excited band of phenanthroline, that is, charge-transfer (CT), and intramolecular benzene excimer formation, which govern its dual-emission behavior. After excitation of the lowest excited band of dibenzophenanthroline, with λexc = 500 nm DBP6 in DCM exhibits dominant excimer emission at 570 nm with a long-lived fluorescence lifetime of 12 ns. This emission is attributed to stable π-π interactions between side phenyl rings. In contrast, excitation λexc = 440 nm leads, in addition to excimer formation, also to weak S1 emission at 480 nm (t = 0.34 ns). Higher-energy excitation λexc < 370 nm reveals ultrafast CT state formation as an intermediate bridging S1 depopulation and excimer generation. Solvent polarity-dependent studies demonstrate a progressive red-shift in S1 emission (455 nm in toluene to 515 nm in ethanol) confirming CT state stabilization in polar environments. DFT simulations corroborate experimental results, predicting S1 emission at 495 nm. By varying excitation wavelength and solvent polarity, DBP6's dual emission can be tuned, highlighting its potential for ratiometric sensing, stable organic light-emitting diodes (OLEDs), and energy conversion systems. This work advances the understanding of nonlinear heteroacenes and provides a framework for designing optoelectronic materials with tailored excited-state interactions.
12 Jul 20:18
by Pengcheng Jin,
Mengke Li,
Wen‐Tao Su,
Shu‐Hang Zhan,
Xiliang Chen,
Huaming Sun,
Ben Yang,
Shi‐Jian Su,
Dong‐Sheng Liu,
Jian‐Yong Hu
Three types of fused carbazole pure fluorescence molecules with double boron multiple resonance (MR) effect are successfully synthesized using a one-pot boron cyclization method, enabling narrowband emission (λPL: 25 nm; λEL: 37 nm) and high luminous efficiency (EQEmax: 25.2%, L
max: 96380 cd m−2) in green OLEDs.
Abstract
This work proposes a strategy of fusing two multiple resonance (MR) units (boron/oxygen) with carbazole as a π-bridge. This approach successfully yielded three narrowband green pure fluorescent materials, namely, DtBO-CzP, DtBO-CzMeP, and DtBO-CztBuP. TADF-sensitized OLEDs based on the target compound exhibited high performance, with their FWHM being less than 40 nm, which is lower than that of other traditional fluorescent materials (>50 nm). It is worth noting that the maximum EQE of devices based on DtBO-CzMeP is 25.2% and the maximum brightness exceeds 90 000 cd m−2, which is relatively high in green pure fluorescent TSF-OLEDs. This work not only enriches the diversity of narrowband pure fluorescent materials but also offers a unique strategy for the design of narrowband fused polycyclic aromatic hydrocarbons.
12 Jul 20:18
by Xiaojuan Song,
Xiaoning Li,
Xiyun Ye,
Yujun Xie,
Yuewei Zhang,
Lian Duan,
Zhen Li
The integration of the peripheral acceptor into the MR skeleton of tBuCzB can promote the LUMO extension, resulting in hybridized short-range and long-range charge transfer, thereby causing redshifted emission without spectral broadening. The OLED devices achieve EQEmax of 26.3% with minimal roll-off, maintaining an EQE of 25.2%, 20.2%, and 18.0% at luminance of 1000, 5000, and 10 000 cd m−2, respectively.
Abstract
Multiple-resonance thermally activated delayed fluorescence (MR-TADF) emitters have shown great potential for ultrahigh-definition organic light-emitting diode (OLED), owing to their high emission efficiency and distinctive narrowband spectra. However, their electroluminescent performance often suffers from significant efficiency roll-off at high luminance due to the slow reverse intersystem crossing rate. Based on the prototypal MR skeleton, the integration of electron donor does not exhibit long-range charge transfer nature, which cannot achieve significant regulation in luminous properties. Herein, by grafting the electron acceptor, the MR-TADF emitter demonstrates hybridized transition characteristic of short-range and long-range charge transfer, leading to enhanced spin-orbit coupling and redshifted emission without spectral broadening. Consequently, the emitter exhibits pure green narrowband emission, featuring a high quantum yield of 88%. In OLED devices, it achieves a maximum external quantum efficiency (EQE) of 22.2%. Meanwhile, the phosphor sensitized devices show an EQE of 26.3% with minimal efficiency roll-off. Notably, they maintain EQE values at a top-tier level of 25.2%, 20.2%, and 18.0% at high luminance of 1000, 5000, and 10 000 cd m−2, respectively. This work demonstrates the peripheral substituent's influence on luminous properties and presents a feasible approach to alleviate the efficiency roll-off issues for MR-TADF emitters in OLED.
12 Jul 20:17
by Jun‐Tao Hu,
Guo‐Xi Yang,
Mengke Li,
Zhizhi Li,
Yitong Zeng,
Zhihai Yang,
Yu Fu,
Xiangyi Cheng,
Yongxia Ren,
Shaofeng Chen,
Kunkun Liu,
Shi‐Jian Su
![Antiaromatic Azepino[3,2,1-jk]Carbazole-Based π-Extended Molecular Engineering for High-Efficiency and Stable BT.2020 Green OLEDs](https://advanced.onlinelibrary.wiley.com/cms/asset/9db51265-1d90-4612-8460-bb8fe6318b17/adom202501147-gra-0001-m.png)
Four multiple-resonance thermally activated delayed fluorescence materials are developed via π-extended molecular engineering by strategically fusing an antiaromatic azepino[3,2,1-jk]carbazole fragment into boron-nitrogen frameworks, achieving high-efficiency, narrowband green emission with exceptional color purity and extended operational stability.
Abstract
Multiple-resonance thermally activated delayed fluorescence (MR-TADF) materials have shown great potential as contenders for next-generation displays with wider color gamut and ultra-high definition (UHD) display, attributed to its narrowband emission and ability to utilize triplet excitons. However, achieving MR-TADF materials and corresponding devices with high efficiency, long operational lifetime, and ultra-pure green emission that meet the Broadcast Service Television 2020 (BT.2020) standard is a major challenge in the field of organic light-emitting diodes (OLEDs). Herein, a π-extended molecular engineering strategy is proposed for developing superior green emitters, exemplified by ACz-BNx (x = 1, 2, 3, 4), which integrates an antiaromatic azepino[3,2,1-jk]carbazole (ACz) fragment into a well-established boron/nitrogen-based MR framework. The proof-of-concept compounds exhibit near-unity photoluminescent quantum yields and high molecular rigidity, along with exceptional electroluminescent stability. Corresponding green top-emission OLED devices achieve remarkable operational stability, with an LT95 lifetime of 434.9 h at an initial luminance of 1000 cd m−2 as well as high color purity that closely aligns the green BT.2020 standard and outstanding external quantum efficiencies of 38.8–52.2%.
12 Jul 20:16
by Hwan‐Hee Cho,
Daniel G. Congrave,
Sebastian Gorgon,
Victor Riesgo‐Gonzalez,
Richard H. Friend,
Hugo Bronstein
This work presents the development of efficient blue thermally activated delayed fluorescent (TADF) materials that perform well without doping, enabling simplified, matrix-free hyperfluorescence (MFHF) OLEDs. When combined with encapsulated narrow-band emitters, the TADF materials serve as effective hosts resulting in pure blue, ultranarrow emission (EQE > 20%, CIEy ≈ 0.15, FWHM ≤ 15 nm).
Abstract
Hyperfluorescence has been proposed as a promising approach for simultaneously efficient and stable blue electroluminescence. Two-component matrix-free hyperfluorescence (MFHF) is particularly appealing to simplify device fabrication but is limited by the availability of suitable blue thermally activated delayed fluorescent (TADF) hosts. In this work, blue TADF materials are developed with high non-doped OLED performance and apply them as hosts in MFHF devices. High maximum external quantum efficiencies (EQEs) of up to 23.2% are achieved from blue non-doped TADF organic light emitting diodes (OLEDs), facilitating efficient MFHF devices with ultranarrow pure blue emission (EQE > 20%, CIEy ≈ 0.15 and full-width at half-maximum ≤15 nm) upon incorporation of a narrowband terminal emitter with multi-resonance spectral features. Steady-state and transient photophysical studies support the high performance of non-doped TADF and MFHF OLEDs. Our results indicate that optimizing TADF hosts for intrinsic non-doped device efficiency is a viable direction to realize high-performing pure blue MFHF OLEDs based on a simple host-guest emissive system.
12 Jul 20:16
by Kelvine Letellier,
Yue‐Jian Yang,
Wei Gao,
Dong‐Ying Zhou,
Denis Ari,
Cassandre Quinton,
Zuo‐Quan Jiang,
Cyril Poriel
We report spiro-configured hosts constructed on the assembly of a quinolinoacrdine unit and different fluorene positional isomers for high-performance blue MR-TADF Organic Light-Emitting Diodess. The v-DABNA:CN-Ir emissive layer combination with SQA-4-FPOPh2 as host shows a narrowband emission peak and a high maximum external quantum efficiency of 22.9%. The molecular orientation is proposed to be a key parameter in these performances.
Abstract
Improving the performance of blue-emitting devices is one of the most important challenges in Organic Light-Emitting Diodes (OLEDs). In recent years, Multi-Resonance Thermally Activated Delayed Fluorescence (MR-TADF) with a phosphorescent sensitization technique has shown its potential to enhance efficiency and mitigate efficiency roll-off. It is reported herein the investigations on the design, the synthesis, and the study of quinolinoacridine-based positional isomers (SQA-1-FPOPh2
, SQA-3-FPOPh2, and SQA-4-FPOPh2
) as host for blue phosphorescence-sensitized MR-TADF OLEDs. The molecular design strategy involves the spatial separation of the electron-rich (quinolinoacridine) and electron-poor (fluorene/diphenylphosphine oxide) fragments. The impact of the π-conjugation disruption between the fluorene and the diphenylphosphine oxide on the electronic properties of the materials is discussed. These bipolar materials are successfully incorporated as hosts in blue MR-TADF OLEDs employing different emitters BNCz or v-DABNA and different phosphorescent sensitizers, FIrpic, CN-Ir, or fac-Ir(tpz)3. Remarkably, when used with the v-DABNA: CN-Ir combination (0.5:20 wt.% respectively), SQA-4-FPOPh2
presents excellent electroluminescent performances. These devices possess a narrowband emission peak at 472 nm, a full width at half-maximum of 21 nm, and a high maximum external quantum efficiency of 22.9%. The excellent molecular orientation, which maximizes the light outcoupling efficiency (η
out), is proposed to be the origin of this high performance.
12 Jul 20:15
by Masashi Mamada,
Thanh Ba Nguyen,
Hajime Nakanotani,
Takuji Hatakeyama,
Chihaya Adachi
Toward a better understanding of stability for blue thermally activated delayed fluorescence (TADF) materials in organic light-emitting diodes (OLEDs), a series of molecules with carbazole donors and benzonitrile acceptors is rationally compared. Experimental data analysis for their photophysical properties and device performances reveals the critical parameter inducing the degradation.
Abstract
Organic light-emitting diodes (OLEDs) have achieved remarkable commercial success in displays for mobile phones and televisions, while blue OLEDs still have a drawback in triplet utilization. Hyperfluorescence OLEDs utilizing thermally activated delayed fluorescence (TADF) represent a promising technology for achieving high efficiency and color-purity. However, their overall performance, including device durability, remains significantly below industrial requirements. In particular, one still has to face the lack of understanding of the relationship between the photophysical properties of TADF materials and their stability. To date, many studies have suggested that shorter exciton lifetimes, which suppress annihilation processes, can help enhance device lifetimes. In this work, however, the correlation between device lifetime and the photophysical properties of four TADF emitters is investigated and find a noticeable decrease in stability with increasing excited-state energy levels, indicating that higher excited-state energies (S1+T1 energies > 5.4 eV) have a substantial impact on device degradation. While improved color purity can be achieved by using a TADF assistant dopant with a shorter emission wavelength, the energy levels must be confined within a specific range to balance efficiency and device lifetime effectively. This study provides practical guidelines for improving device stability and performance.
12 Jul 19:59
by Kateřina Teichmanová,
Stanislav Luňák Jr.,
Karel Pauk,
Lukáš Střižík,
Zdeňka Růžičková,
Tomáš Mikysek,
Klára Melánová,
Aleš Imramovský,
Kazuhiko Nagura
Novel merocyanine derivatives with a strong diphenyl-dihydrophenazine donor and a series of strong electron acceptors were developed. The indanone and indandione acceptor units were modified by dicyanovinylene groups to tune acceptor strength. Among these derivatives, DPPZ-IDD realized an ultranarrow electrochemical gap of 0.93 eV and an optical band gap of 1.09 eV. Fluorescence in the visible to NIR region was also achieved in solution and solid states.
Abstract
Five merocyanine derivatives with a 5,10-diphenyl-dihydrophenazine donor and various indanone-and indandione based-acceptors with one or two dicyanovinylene groups were prepared by Knoevenagel condensation for tuning absorption and fluorescence in the near-infrared region. Molecular conformation, bond length alternation, and molecular packing in the solid state were studied by X-ray diffraction of single crystals in combination with density functional theory (DFT) calculations. By enhancing electron-accepting ability, a considerable decrease of lowest unoccupied molecular orbitals (LUMO) energy by 1.01 eV and retained highest occupied molecular orbitals (HOMO) energy within 0.13 eV were estimated by cyclic and rotating disc electrode voltammetry, relating semi-quantitatively to DFT prediction. Optical properties in solutions with various polarity, neat amorphous films, and crystalline powder states were studied. The absorption maxima of the neat films evolved from 545 nm to 931 nm. An ultranarrow optical band gap of DPPZ-IDD (1.09 eV) was found from the onset of thin film absorption and well agreed with the electrochemical gap of 0.93 eV. Detectable fluorescence in the NIR region was observed in the film and polycrystalline powder states.
11 Jul 20:26
by Chuluo Yang,
Mao Quan,
Ze-Lin Zhu,
Guohao Chen,
Jingsheng Miao
Utilizing a sequential borylation strategy, we constructed a deuterium pure-green MR-TADF emitter. The associated device achieved narrowband emission with a full width at half maximum (FWHM) of 25 nm, CIE coordinates of (0.16, 0.75), a maximum external quantum efficiency (EQE) of 34.6% with minimal efficiency roll-off and a lifetime (LT80) of 6078 h at an initial luminance of 1000 cd m−2.
Abstract
Multi-resonance thermally activated delayed fluorescence (MR-TADF) emitters, especially high-order B/N MR-TADF emitters, offer new opportunities in obtaining wide-color-gamut, high color purity, and highly efficient organic light-emitting diodes (OLEDs). Extending the device durability is still very challengeable for these emitters. Deuteration of emitters to slow down their degradation and lengthen device lifespan is a promising strategy. However, how to access deuterated high-order MR-TADF emitters remains to be explored. Herein, a synthetic protocol of high-order B/N products is proposed using deuterated starting materials and sequential borylation. Combining with fine-tuning electronic effect through adjusting position of tert-butyl (
t
Bu) substituents, we successfully obtained deuterated triboron MR-TADF material ω’-DABNA-D that delivers precisely tuned pure-green emission with close-to-unity quantum yield and rapid reverse intersystem crossing (RISC). The resulting binary OLED approaches the BT.2020 standard with CIE coordinates of (0.16, 0.75) and demonstrates impressive external quantum efficiency (EQE) of 34.6% at maximum and 30.7% at 1000 cd m−2. Additionally, an Ir(ppy)3-sensitized device shows excellent operational stability, with an extrapolated lifetime (LT80) of 6078 h at an initial luminance of 1000 cd m−2. This study hence offers a promising methodology toward high-performance OLED with long device lifetime.
11 Jul 14:13
J. Mater. Chem. C, 2025, 13,17416-17457
DOI: 10.1039/D5TC01861G, Review Article
P. Keerthika, Venkatramaiah Nutalapati, Rajendra Kumar Konidena
This review highlights the recent advances in multi-resonance thermally activated delayed fluorescence emitters for OLEDs, focusing on molecular strategies to overcome challenges such as color tunability, exciton dynamics, and device stability.
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11 Jul 14:10
J. Mater. Chem. C, 2025, 13,16998-17008
DOI: 10.1039/D5TC02275D, Paper
Haoyu Ma, Xiaoling Niu, Wenlong Qu, Zhen Feng, Tiantian Ma, Yongliang Liu, Shengbo Zhu
Incorporating AIE and HLCT moieties, a blue fluorescence emitter (CF3-PPI-TPE) with AIE and HLCT properties was obtained. It exhibits obvious color changes under acid gas, and shows narrow emission in OLED applications.
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11 Jul 14:10
J. Mater. Chem. C, 2025, 13,16946-16953
DOI: 10.1039/D5TC02304A, Paper
Rundong Tian, Zhi Yang, Zihan Wang, Jinxin Dong, Weihao Li, Guangfu Li, Hui Xu
Steric hindrance effects, MR-TADF, and TSCT have been integrated into non-conjugated polymers to achieve highly efficient MR-TADF emission with near-unity PLQY. Solution-processed OLEDs achieve a maximum external quantum efficiency (EQE) of 12.7%.
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11 Jul 14:09
J. Mater. Chem. C, 2025, 13,16489-16498
DOI: 10.1039/D5TC01155H, Paper
Laure de Thieulloy, Leonardo Evaristo de Sousa, Piotr de Silva
Molecules with an inverted singlet–triplet gap violate Hund's rule and offer promising applications in photoactive materials.
The content of this RSS Feed (c) The Royal Society of Chemistry
07 Jul 14:28
by Yuntao Liu,
Wenbin Chen,
Zafar Mahmood,
Xitong He,
Weiqiang Li,
Hui Liang,
Ming‐De Li,
Yanping Huo,
Shaomin Ji
Employing symmetry-breaking π–π interactions by tethering two MR scaffolds into a dimer, precise excited-state orbital control is achieved, enabling efficient spin-flipping while retaining narrow emission. Remarkably, an efficient photoinitiating system based on this material is developed, which derive olefin polymerization to 99% conversion under ultra-low-energy visible light (10 mW cm⁻2), highlighting their potential for advanced photochemical applications.
Abstract
Multi-resonance thermally activated delayed fluorescence (MR-TADF) materials are renowned for their excellent color purity; however, their functional versatility and potential for interdisciplinary integration are constrained by the inherently poor spin-flipping and intersystem crossing (ISC) efficiencies. Herein, this challenge is overcome through an innovative strategy of leveraging symmetry-breaking π–π interactions by tethering two MR scaffolds into a dimer (DBNCz), enabling the precise control over excited-state properties. It is showed that dimer design alters the orbital nature of selective high-lying excited states, generating densely packed, degenerate hybrid locally-excited (LE)/charge transfer (CT) states, resulting in the enhanced spin-orbit coupling (SOC) and significantly improvement in the spin-flipping process. Compared to monomeric MR (BNCz), which exhibited inefficient ISC (ΦΔ = 3%; k
ISC = 2.14 × 10⁷ s⁻¹), the dimer DBNCz demonstrated nearly ten-folds enhancement (ΦΔ = 40%; k
ISC = 12.7 × 10⁷ s⁻¹) while retaining its narrowband emission. Utilizing these MR-emitters, a novel photoinitiating system is developed, achieving 98% olefin polymerization under low-energy visible-light irradiation (450 nm) within 40 s, surpassing commercial benchmarks. This work not only enhances the fundamental photophysical processes of MR-TADF emitters but also paves the way for their advancement in photocatalytic applications, unlocking new opportunities for the development of high-performance functional materials.
07 Jul 14:26
by Mingliang Xie,
Chenglin Ma,
Yannan Zhou,
Jingru Song,
Li Zhang,
Shi‐Tong Zhang,
Qikun Sun,
Wenjun Yang,
Shanfeng Xue
Two simple deep blue HLCT materials are developed. The doped OLEDs based on PdCz-2CN achieve ultra-deep blue emission with CIEy coordinates of 0.037, which is very close to the BT.2020 standard. Remarkedly, the non-doped exciplex OLED based on PdCz-2CN: 15 wt.%TAPC as the luminescent layer achieves the EQEmax of 15.44%, and PdCz-2CN: 15 wt.%TAPC exciplex-based as the host, red phosphor Ir(MDQ)2(acac) as the guest of the host-guest doped device reaches the EQEmax as high as 20.14%.
Abstract
Hybrid local and charge transfer (HLCT) emitters have received much attention because they can utilize triplet exciton via hot exciton channels. However, exploiting novel multifunctional deep-blue HLCT materials capable of high color purity remains a great challenge. Herein, two deep-blue emitters with HLCT properties, PdCz-2CN and mPdCz-2CN, aresynthesized. The non-doped OLED based on PdCz-2CN or mPdCz-2CN emitter with EQEmax and Commission Internationale de l'Eclairage (CIE) coordinates Y values of 5.42%@0.062 and 2.05@0.064, respectively. More importantly, the doped-OLEDs achieve ultra deep-blue emission with EQEmax and CIEy values of 5.10%@0.037 and 1.96%@0.050, respectively, which is close to the BT.2020 standard. In addition, the PdCz-2CN can not only obtain ultra-deep blue OLED, but also realize the exciplex-OLED as the electron acceptor for realizing multifunctional luminescence. As a result, the non-doped exciplex OLED based on PdCz-2CN: 15 wt.%TAPC as the luminescent layer achieves 15.44% EQEmax via forming green exciplex emission with hole transport layer TAPC. Moreover, PdCz-2CN: 15 wt.%TAPC exciplex-based as the host, red phosphor Ir(MDQ)2(acac) as the guest of OLED reaches red emission, and the EQEmax isup to 20.14%. This study is the first deep-blue HLCT emitter using picolinonitrile as an electron acceptor, having significant potential for efficient exciplex OLED applications.
07 Jul 14:23
by Hong‐Ji Tan,
Jia‐Li Liu,
Jie‐Rong Yu,
Guo‐Xi Yang,
Xiu‐Qi Gao,
Bing Wang,
Zhi‐Qiang Long,
Qing‐Xiao Tong,
Jing‐Xin Jian,
Shi‐Jian Su,
Ze‐Lin Zhu,
Chun‐Sing Lee
The C═O/N-C/N multiple-resonance (MR) emitter DPQAO-ICz shows green emission at 504 nm (full-width-at-half-maximum [FWHM] = 26 nm) with 92% photoluminescence quantum yield. Oranic light-emitting diodes (OLEDs) of DPQAO-ICz achieve 515 nm emission (FWHM = 34 nm), CIEy = 0.68, and 25.9% EQE (external quantum efficiency). Hyper-OLED reaches 31.6% EQE (514 nm, FWHM = 34 nm). This MR hybridization extends π-conjugation while maintaining narrow FWHM, enabling efficient green emitters.
Abstract
In next-generation displays, green emission carries weight for widening the color gamut comparing to blue and red emissions. Multi-resonant (MR) emitters hold great potential in meeting the new BT.2020 color purity. However, C/N and C═O/N-based pure-green MR systems remain underdeveloped despite their synthetic accessibility. Here, a successful case is presented by merging C/N and C═O/N MR cores into a hybrid MR system, forming a new pure green emitter, DPQAO-ICz. The new molecule simultaneously maintains the MR character of its parent cores and effectively redshifts the emission to the target green region with a peak/full-width-at-half-maximum (FWHM) of 504/26 nm in toluene. The enhanced transition oscillator strength endows DPQAO-ICz with improved photoluminescence quantum yield up to 92% in the doped film. Organic light-emitting diodes (OLEDs) based on DPQAO-ICz deliver pure green emission peaking at 515 nm with FWHM of 34 nm, cutting-edge CIEy and maximum external quantum efficiency (EQEmax) of 0.68 and 25.9% among reported C/N- and C═O/N-based MR emitters. The EQEmax was boosted to 31.6% in the hyper-OLED. This study exemplifies an effective method to considerably extend the π plane to reduce the energy gap of emitters. The method also enables redshifted narrowband emission without sacrificing oscillator strength and broadening FWHM.
07 Jul 14:21
by Tao Li,
Guimin Zhao,
Yuanyuan Li,
Kun Lyu,
Wenchao Xie,
Zhenni Bai,
Xinliang Ding,
Ronghao Yang,
Zhicai Chen,
Zhihua Ma,
Xin Ai,
Wei Jiang,
Yanpei Wang,
Fangfang Huang,
Shiyang Shao
Carbocation-based multiresonance thermally activated delayed fluorescent emitters featuring small energy gaps of less than 2.20 eV have been developed by doping positively charged carbenium ions as strong electron-deficient groups and nitrogen as an electron-rich atom into a polycyclic aromatic skeleton. The resulting solution-processed OLEDs showed a yellow narrowband emission with an external quantum efficiency of 29.4%.
Abstract
Multiresonance thermally activated delayed fluorescent (MR-TADF) emitters hold great promise for ultrahigh-definition displays, but are fundamentally restricted to wide-energy-gap heteropolycyclic systems typically with blue-to-green emissions, while their yellow-to-red emissions remain a major challenge. Here we propose a strategy for developing MR-TADF emitters with narrow energy gaps (less than 2.20 eV) by doping positively-charged carbenium ion (C+) into polycyclic skeletons to create strong short-range charge transfer with electron-rich nitrogen atoms, achieving a significant 160 nm emission redshift compared to the benchmark neutral boron-based counterpart. Furthermore, steric isopropyl groups and bulky tetrakis(pentafluorophenyl)borate counter ions are synergistically integrated to suppress intermolecular aggregation, yielding high solid-state photoluminescence quantum efficiencies up to 90%. Solution-processed organic light-emitting diodes based on the emitters exhibit promising external quantum efficiency of 29.4% with narrow full-width at half-maximum of 0.17 eV, opening the way for development of ion-based MR-TADF emitters toward efficient long-wavelength narrowband electroluminescence.
07 Jul 14:20
by Xia Wang,
Zhe Zhang,
Huili Ma,
Zuju Ma,
Mengjia Yuan,
Haijiang Bian,
Yicen Liu,
Xingyun Luo,
Fuyin Ma,
Yanlong Wang,
Yihui Yuan,
Ning Wang,
Shuao Wang,
Wei Liu
The discovery of a T1-blocked TADF mechanism within an AIE-active molecule not only broadens the scope of available TADF materials but also pioneers the incorporation of the TADF effect in metal-organic frameworks.
Abstract
Scintillators play vital roles in fields such as medical imaging, high-energy physics, astronomy, and radiation monitoring. Their operational principle, rooted in the excitation of high-energy radiation, underscores that luminescence efficiency in scintillators is fundamentally limited by their capacity to harness triplet excitons. In this context, thermally activated delayed fluorescence (TADF) molecules present a promising avenue, enabling the efficient utilization of triplet excitons through thermally activated up-conversion, thereby advancing the development of superior scintillators. Our investigation reveals a T1-blocked TADF mechanism in H4TCPE, where efficient singlet-triplet exciton transfer arises from the minimized S1-T2 energy gap (0.18 eV). Unlike conventional TADF molecules, H4TCPE features carboxylic acid groups that enable heavy metal coordination to enhance X-ray attenuation. Using tetravalent metals (Zr, Hf, and Th) as nodes and H4TCPE as linkers, we fabricated metal-organic frameworks (MOFs) that synergize H4TCPE's TADF properties with metal-enhanced radiation absorption. The resulting MOFs show X-ray detection and imaging performances superior to pure H4TCPE (20.0 lp mm−1 and 1.15 µGy s−1 for Th-TCPE vs. <14.3 lp mm−1 and 5.01 µGy s−1 for H4TCPE), with efficacy correlating to metal atomic number. This work not only broadens TADF molecular diversity through a new energy transfer mechanism and pioneers TADF-MOF integration for advanced radiation detection.
07 Jul 13:16
by Heechan Kim and Robert J. Gilliard, Jr.
Journal of the American Chemical Society
DOI: 10.1021/jacs.5c07436
07 Jul 13:12
by Longfei Nan, Pei He, Tingwei Zhang, Yiran Dong, Chao Feng, Tong He, Pengfei Li, Yanfeng Zhang, Yong Nie, and Jiao Jiao
Journal of the American Chemical Society
DOI: 10.1021/jacs.5c03381
07 Jul 13:11
by Jinge Zhu, Rui Zeng, Erjun Zhou, Chao Li, Jiawei Deng, Mengzhen Du, Qing Guo, Mengwei Ji, Zongtao Wang, Yi Lin, Fei Han, Jiaxin Zhuang, Senke Tan, Lixuan Kan, Lei Zhu, Ming Zhang, and Feng Liu
Journal of the American Chemical Society
DOI: 10.1021/jacs.5c04656
17 Jun 11:07
Chem. Sci., 2025, 16,12277-12292
DOI: 10.1039/D5SC02409A, Review Article
Open Access
Ming-Jun Ji, Meng Li, Chuan-Feng Chen
This review provides an overview of the recent advances in co-assembly systems with circularly polarized luminescence properties based on macromolecules.
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16 Jun 11:51
by Sipeng Wang,
Shengfu Wu,
Runjia Wang,
Jie Lu,
Minghua Liu
Two novel Aggregation-Induced Emission (AIE) active macrocycle structures (CP1, CP2) were designed and synthesized. Compared to the macrocycle
R
CP2 containing phenyl spacers, the rigid
R
CP1 macrocycle self-assembled into left-handed microhelix by body-centered cubic (BCC) supramolecular packing with left-handed tendency, resulting in circularly polarized luminescence materials with high luminescence dissymmetry factor (g
lum) value.
Abstract
The design and assembly of chiral macrocycles remain an underexplored frontier in supramolecular science. In this study, we synthesized a pair of enantiomeric macrocyclic molecules (CP1) through the condensation of chiral cyclohexanediamine with tetraphenylethylene (TPE) dialdehyde. These molecules exhibited remarkable circular dichroism (CD) and circularly polarized luminescence (CPL) properties at the supramolecular level. Through supramolecular assembly in mixed solvent systems, we achieved a rare micron-scale helical structure, exhibiting a high luminescence dissymmetry factor (g
lum) of 0.32—one of the highest values reported to date for macrocyclic self-assemblies. Furthermore, by designing a chiral macrocycle with phenyl spacers (CP2), we revealed that the confinement of macrocycles and restricted internal molecular rotation are critical for achieving high g
lum values and helical structure formation. This work not only advances the design of chiral macrocycles but also provides new insights into the relationship between molecular structure and supramolecular assembly, paving the way for the development of advanced chiral materials with potential applications in optics, sensing, and nanotechnology.
11 Jun 13:14
by Jingxiang Wang,
Hassan Hafeez,
Dongyang Chen,
Jhon Sebastian Oviedo Ortiz,
Yan Xu,
Aidan P. McKay,
David B. Cordes,
Jeanne Crassous,
Ifor D. W. Samuel,
Eli Zysman-Colman
The selenium-based tBuCz-DiKTaSe emitter containing a twisted ortho-disposed tert-butylcarbazole shows high ΦPL, suppressed ACQ, fast k
RISC and is chiral. The OLEDs show high EQEmax and alleviated efficiency roll-off compared to devices with carbonyl-based MR-TADF emitters.
Abstract
Nitrogen/carbonyl (N/C═O) based multi-resonant thermally activated delayed fluorescence (MR-TADF) emitters are attractive due to their bright, narrowband emission and the ease with which they can be synthesized. However, their photophysics typically suffer from slow reverse intersystem crossing (RISC) because of their relatively large singlet-triplet energy gap (ΔE
ST). Thus, the organic light-emitting diodes (OLEDs) with these emitters typically show severe efficiency roll-off. Here, two MR-TADF emitters DiKTaSe and tBuCz-DiKTaSe have been designed and synthesized. The introduction of selenium in the form of an annelated benzoselenophene enhances spin-orbit coupling and increases the RISC rate. The twisted ortho-substituted tert-butylcarbazole moiety in tBuCz-DiKTaSe helps to suppress aggregation-caused quenching of the emission in films. In addition, the large size of the selenium atom and long C─Se bonds induce helical chirality in both DiKTaSe and tBuCz-DiKTaSe. Finally, the OLEDs with DiKTaSe showed maximum external quantum efficiency (EQEmax) of 22.7% while OLEDs with tBuCz-DiKTaSe showed a higher EQEmax of 27.8% and less-pronounced efficiency roll-off, with EQE at 100 cd m−2 (EQE100)/ EQE at 1000 cd m−2 (EQE1000) of 23.5/12.5%. These efficiency values are amongst the highest of devices employing DiKTa-based emitters. Our work provides key insight into how to judiciously employ heavy atoms to increase the performance of the emitter and the device.
11 Jun 12:53
by Hua Gu, Puan Yuan, Juan Zhang, Xiang Xia, Qingze Pan, Wenkai Liu, Xueze Zhao, Wen Sun, Jianjun Du, Jiangli Fan, and Xiaojun Peng
Journal of the American Chemical Society
DOI: 10.1021/jacs.5c04044
