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Effect of aggregation on thermally activated delayed fluorescence and ultralong organic phosphorescence:QM/MM study
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作者 张群 王晓菲 +6 位作者 吴智敏 李小芳 张凯 宋玉志 范建忠 王传奎 蔺丽丽 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第10期410-419,共10页
Aggregation-induced thermally activated delayed fluorescence(TADF)phenomena have attracted extensive attention recently.In this paper,several theoretical models including monomer,dimer,and complex are used for the exp... Aggregation-induced thermally activated delayed fluorescence(TADF)phenomena have attracted extensive attention recently.In this paper,several theoretical models including monomer,dimer,and complex are used for the explanation of the luminescent properties of(R)-5-(9H-carbazol-9-yl)-2-(1,2,3,4-tetrahydronaphthalen-1-yl)isoindoline-1,3-dione((R)-ImNCz),which was recently reported[Chemical Engineering Journal 418129167(2021)].The polarizable continuum model(PCM)and the combined quantum mechanics and molecular mechanics(QM/MM)method are adopted in simulation of the property of the molecule in the gas phase,solvated in acetonitrile and in aggregation states.It is found that large spin–orbit coupling(SOC)constants and a smaller energy gap between the first singlet excited state and the first triplet excited state(△E_(st))in prism-like single crystals(SC_(p)-form)are responsible for the TADF of(R)-lmNCz,while no TADF is found in block-like single crystals(SC_(b)-form)with a larger △E_(st).The multiple ultralong phosphorescence(UOP)peaks in the spectrum are of complex origins,and they are related not only to ImNCz but also to a minor amount of impurities(ImNBd)in the crystal prepared in the laboratory.The dimer has similar phosphorescence emission wavelengths to the(R)-lmNCz-SC_(p) monomers.The complex composed of(R)-lmNCz and(R)-lmNBd contributes to the phosphorescent emission peak at about 600 nm,and the phosphorescent emission peak at about 650 nm is generated by(R)-lmNBd.This indicates that the impurity could also contribute to emission in molecular crystals.The present calculations clarify the relationship between the molecular aggregation and the light-emitting properties of the TADF emitters and will therefore be helpful for the design of potentially more useful TADF emitters. 展开更多
关键词 organic light-emitting diodes thermally activated delayed fluorescence ultralong organic phosphorescence aggregation mode
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Effect of Delay Chilling on μ-calpain Activities and the Tenderness of Bovine M. longissimus
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作者 胡鹏 丁玉 +1 位作者 梁荣蓉 罗欣 《Agricultural Science & Technology》 CAS 2010年第5期90-92,158,共4页
μ-calpain activities and shear force values of bovine M. longissimus from Chinese Yellow crossbred bulls were analyzed,and the effect of delay chilling on μ-calpain activities and the tenderness of beef during postm... μ-calpain activities and shear force values of bovine M. longissimus from Chinese Yellow crossbred bulls were analyzed,and the effect of delay chilling on μ-calpain activities and the tenderness of beef during postmortem aging were studied. The results showed that delay chilling significantly improved μ-calpain activities (P<0.05) and enhanced the tenderness of bovine M. longissimus during earlier aging periods compared with conventional chilling. But in later aging periods,delay chilling weakened the effect on the tenderness of beef because of premature consumption of μ-calpain. The experiment results confirmed that delay chilling improved the rate of postmortem aging of beef and remarkably enhanced the tenderness of beef through the effect of delay chilling on μ-calpain activities. 展开更多
关键词 delay chilling Shear force values Tendemess μ-calpain activities
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First-Principles Investigation on Triazine Based Thermally Activated Delayed Fluorescence Emitters
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作者 范建忠 邱帅 +1 位作者 蔺丽丽 王传奎 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2016年第3期291-296,I0001,共7页
Three kinds of triazine based organic molecules designed for thermally activated delayed fluorescence (TADF) emitters are investigated by first-principles calculations. An optimal Hartree-Fork (HF) method is adopt... Three kinds of triazine based organic molecules designed for thermally activated delayed fluorescence (TADF) emitters are investigated by first-principles calculations. An optimal Hartree-Fork (HF) method is adopted for the calculation of energy gap between the first singlet state (S1) and the first triplet state (T1). The natural transition orbital, the electron- hole (e-h) distribution and the e-h overlap diagram indicate that the S1 states for the three systems include both charge-transfer and some localized excitation component. Further quantitative analysis of the excitation property is performed by introducing the index Ar and the integral of e-h overlap S. It is found that symmetric geometry is a necessary condition for TADF emitters, which can provide more delocalized transition orbitals and consequently a small S1-T1 energy gap. Artful inserting aromatic groups between donors and acceptors can significantly enhance the oscillator strength. Finally, the energy state structures calculated with the optimal HF method is presented, which can provide basis for the study of the dynamics of excited states. 展开更多
关键词 FIRST-PRINCIPLES Thermally activated delayed fluorescence Charge-transferstates
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Enhancement of Frster energy transfer from thermally activated delayed fluorophores layer to ultrathin phosphor layer for high color stability in non-doped hybrid white organic light-emitting devices 被引量:1
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作者 王子君 赵娟 +2 位作者 周畅 祁一歌 于军胜 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第4期404-410,共7页
Fluorescence/phosphorescence hybrid white organic light-emitting devices(WOLEDs) based on double emitting layers(EMLs) with high color stability are fabricated.The simplified EMLs consist of a non-doped blue therm... Fluorescence/phosphorescence hybrid white organic light-emitting devices(WOLEDs) based on double emitting layers(EMLs) with high color stability are fabricated.The simplified EMLs consist of a non-doped blue thermally activated delayed fluorescence(TADF) layer using 9,9-dimethyl-9,10-dihydroacridine-diphenylsulfone(DMAC-DPS) and an ultrathin non-doped yellow phosphorescence layer employing bis[2-(4-tertbutylphenyl)benzothiazolato-N,C2']iridium(acetylacetonate)((tbt)_2Ir(acac)).Two kinds of materials of 4,7-diphenyl-1,10-phenanthroline(Bphen) and 1,3,5-tris(2-Nphenylbenzimidazolyl) benzene(TPBi) are selected as the electron transporting layer(ETL),and the thickness of yellow EML is adjusted to optimize device performance.The device based on a 0.3-nm-thick yellow EML and Bphen exhibits high color stability with a slight Commission International de l'Eclairage(CIE) coordinates variation of(0.017,0.009) at a luminance ranging from 52 cd/m^2 to 6998 cd/m^2.The TPBi-based device yields a high efficiency with a maximum external quantum efficiency(EQE),current efficiency,and power efficiency of 10%,21.1 cd/A,and 21.3 lm/W,respectively.The ultrathin yellow EML suppresses hole trapping and short-radius Dexter energy transfer,so that Forster energy transfer(FRET)from DMAC-DPS to(tbt)_2Ir(acac) is dominant,which is beneficial to keep the color stable.The employment of TPBi with higher triplet excited state effectively alleviates the triplet exciton quenching by ETL to improve device efficiency. 展开更多
关键词 white organic light-emitting devices non-doped emitting layers thermally activated delayed fluo-rescence color stability
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High Efficiency and Stable Organic Light-Emitting Diodes Based on Thermally Activated Delayed Fluorescence Emitter
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作者 吕孝鹏 王会 +7 位作者 孟令强 魏晓芳 陈永振 孔祥彬 刘建君 唐建新 汪鹏飞 王鹰 《Chinese Physics Letters》 SCIE CAS CSCD 2016年第8期139-142,共4页
High efficiency, stable organic light-emitting diodes (OLEDs) based on 2-pheyl-4'-carbazole-9-H-Thioxanthen-9- one-10, 10-dioxide (TXO-PhCz) with different doping concentration are constructed. The stability of t... High efficiency, stable organic light-emitting diodes (OLEDs) based on 2-pheyl-4'-carbazole-9-H-Thioxanthen-9- one-10, 10-dioxide (TXO-PhCz) with different doping concentration are constructed. The stability of the encap- sulated devices are investigated in detail. The devices with the 10 wt% doped TXO-PhCz emitter layer (EML) show the best performance with a current efficiency of 52.1 cd/A, a power efficiency of 32.71re^W, and an external quantum efficiency (EQE) of 17.7%. The devices based on the lOwt%-doped TXO-PhCz EML show the best operational stability with a half-life time (LTSO) of 8Oh, which is 8 h longer than that of the reference devices based on fac-tris(2-phenylpyridinato)iridium( Ⅲ) (Ir(ppy)a). These indicate excellent stability of TXO-PhCz for redox and oxidation processes under electrical excitation and TXO-PhCz can be potentially used as the emitters for OLEDs with high efficiency and excellent stability. The high-performance device based on TXO-PhCz with high stability can be further improved by the optimization of the encapsulation technology and the development of a new host for TXO-PhCz. 展开更多
关键词 OLEDs in of High Efficiency and Stable Organic Light-Emitting Diodes Based on Thermally Activated delayed Fluorescence Emitter EML on for
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Theoretical verification of intermolecular hydrogen bond induced thermally activated delayed fluorescence in SOBF-OMe
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作者 Mu-Zhen Li Fei-Yan Li +5 位作者 Qun Zhang Kai Zhang Yu-Zhi Song Jian-Zhong Fan Chuan-Kui Wang Li-Li Lin 《Chinese Physics B》 SCIE EI CAS CSCD 2021年第12期378-384,共7页
Thermally activated delayed fluorescence(TADF)molecules have attracted great attention as high efficient luminescent materials.Most of TADF molecules possess small energy gap between the first singlet excited state(S_... Thermally activated delayed fluorescence(TADF)molecules have attracted great attention as high efficient luminescent materials.Most of TADF molecules possess small energy gap between the first singlet excited state(S_(1))and the first triplet excited state(T_(1))to favor the up-conversion from T_(1)to S_(1).In this paper,a new TADF generation mechanism is revealed based on theoretical simulation.By systematic study of the light-emitting properties of SOBF-OMe in both toluene and in aggregation state,we find that the single SOBF-OMe could not realize TADF emission due to large energy gap as well as small up-conversion rates between S_(1)and T_(1).Through analysis of dimers,we find that dimers with intermolecular hydrogen bond(H-bond)are responsible for the generation of TADF,since smaller energy gap between S_(1)and T_(1)is found and the emission wavelength is in good agreement with experimental counterpart.The emission properties of SOBF-H are also studied for comparison,which reflect the important role of H-bond.Our theoretical results agree ith experimental results well and confirm the mechanism of H-bond induced TADF. 展开更多
关键词 organic light-emitting diodes thermally activated delayed fluorescence intermolecular hydrogen bond decay rates
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Boron-containing Thermally Activated Delayed Blue Fluorescence Materials via Donor Tuning:a Theoretical Study
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作者 Yan-Lin Ji Quan-Song Li 《Chinese Journal of Chemical Physics》 SCIE EI CAS CSCD 2022年第3期499-508,I0002,共11页
Based on the boron-containing thermally activated delayed fuorescence(TADF)compound p-AC(AC:acridine)5,9-dioxa-13 b-boranaphtho[3,2,1-de]anthracene(a),a series of new TADF molecules b1-b4 were designed via adding two ... Based on the boron-containing thermally activated delayed fuorescence(TADF)compound p-AC(AC:acridine)5,9-dioxa-13 b-boranaphtho[3,2,1-de]anthracene(a),a series of new TADF molecules b1-b4 were designed via adding two nitrogen atoms at the AC donor part.Density functional theory and time-dependent density functional theory calculations were performed on the frontier orbital energy levels,emission spectra,singlet-triplet states energy gaps(?EST),reverse intersystem crossing(RISC)rate constant(kRISC)for compounds a and b1-b4.Our calculation results show that the maximum emission wavelengths of b1-b4 are significantly blue-shifted by47-125 nm compared with that of a.Molecules b1 and b3 exhibit dark-blue emission,while molecules b2 and b4 display light-blue emission,indicating that these four derivatives could be potential organic light-emitting diode(OLED)candidates with blue-light emitting.Moreover,we found the RISC processes in a,b2,and b4 can occur not only from T_(1) state to S_(1) state,but also from T_(2) state to S_(1) state significantly,while the RISC processes in b1 and b3 mainly take place via the T_(2)→S_(1) hot exciton way.Importantly,the T_(1)→S_(1) kRISC values of b2 and b4 are predicted to be two to three times of that of a,indicating enhanced TADF property.Our results not only provide two promising boron-based TADF candidates(b2 and b4),but also offer useful theoretical basis for the design of blue OLED materials. 展开更多
关键词 Excited state Thermally activated delayed fuorescence Theoretical study
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Perspective for aggregation-induced delayed fluorescence mechanism:A QM/MM study
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作者 Jie Liu Jianzhong Fan +3 位作者 Kai Zhang Yuchen Zhang Chuan-Kui Wang Lili Lin 《Chinese Physics B》 SCIE EI CAS CSCD 2020年第8期531-537,共7页
To enhance the potential application of thermally activated delayed fluorescence(TADF)molecular materials,new functions are gradually cooperated to the TADF molecules.Aggregation induced emission can effectively solve... To enhance the potential application of thermally activated delayed fluorescence(TADF)molecular materials,new functions are gradually cooperated to the TADF molecules.Aggregation induced emission can effectively solve the fluorescence quenching problem for TADF molecules in solid phase,thus aggregation-induced delayed fluorescence(AIDF)molecules were recently focused.Nevertheless,their luminescent mechanisms are not clear enough.In this work,excited state properties of an AIDF molecule DMF-BP-DMAC[reported in Chemistry-An Asian Journal 14828(2019)]are theoretically studied in tetrahydrofuran(THF)and solid phase.For consideration of surrounding environment,the polarizable continuum method(PCM)and the combined quantum mechanics and molecular mechanics(QM/MM)method were applied for solvent and solid phase,respectively.Due to the increase of the transition dipole moment and decrease of the energy difference between the first single excited state(S1)and the ground state(S0),the radiative rate is increased by about 2 orders of magnitude in solid phase.The energy dissipation of the non-radiative process from S1 to S0 is mainly contributed by low-frequency vibrational modes in solvent,and they can be effectively suppressed in aggregation,which may lead to a slow non-radiation process in solid phase.Both factors would induce enhanced luminescence efficiency of DMF-BP-DMAC in solid phase.Meanwhile,the small energy gap between S1 and triplet excited states results in high reverse intersystem crossing(RISC)rates in both solvent and solid phase.Therefore,TADF is confirmed in both phases.Aggregation significantly influences both the ISC and RISC processes and more RISC channels are involved in solid state.The enhanced delayed fluorescence should be induced by both the enhanced fluorescent efficiency and ISC efficiency.Our calculation provides a reasonable explanation for experimental measurements and helps one to better understand the luminescence mechanism of AIDF molecules. 展开更多
关键词 thermally activated delayed fluorescence aggregation-induced delayed fluorescence the combined quantum mechanics and molecular mechanics method
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Luminescent properties of thermally activated delayed fluorescence molecule with intramolecular π-π interaction between donor and acceptor
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作者 蔡磊 范建忠 +2 位作者 孔祥朋 蔺丽丽 王传奎 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第11期544-549,共6页
Influence of intramolecular π-π interaction on the luminescent properties of thermally activated delayed fluorescence(TADF) molecule(3, 5-bis(3,6-di-tert-butyl-9 H-carbazol-9-yl)-phenyl)(pyridin-4-yl) methan... Influence of intramolecular π-π interaction on the luminescent properties of thermally activated delayed fluorescence(TADF) molecule(3, 5-bis(3,6-di-tert-butyl-9 H-carbazol-9-yl)-phenyl)(pyridin-4-yl) methanone(DTCBPY) is theoretically studied by using the density functional theory(DFT) and time-dependent density functional theory(TD-DFT).Four conformations(named as A, B, C, and D) of the DTCBPY can be found by relax scanning, and the configuration C corresponds to the luminescent molecule detected experimentally. Besides, we calculate the proportion of each conformation by Boltzmann distribution, high configuration ratios(44% and 52%) can be found for C and D. Moreover, C and D are found to exist with an intramolecular π-π interaction between one donor and the acceptor; the intramolecular interaction brings a smaller Huang-Rhys factor and reduced reorganization energy. Our work presents a rational explanation for the experimental results and demonstrates the importance of the intramolecular π-π interaction to the photophysical properties of TADF molecules. 展开更多
关键词 thermally activated delayed fluorescence intramolecular π-π interaction Huang-Rhys factor and reorganization energy aggregation induced enhanced emission
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Heptagonal intramolecular-lock strategy enables high-performance thermally activated delayed fluorescence emitters
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作者 Zhenmei Huang Dezhi Yang +2 位作者 Dongge Ma Zhengyang Bin Jingsong You 《Science China Chemistry》 SCIE EI CAS CSCD 2024年第4期1181-1186,共6页
The development of highly efficient thermally activated delayed fluorescence(TADF)emitters is persistently pursued for the application of organic light-emitting diodes(OLED)in full-colour display and solid-state light... The development of highly efficient thermally activated delayed fluorescence(TADF)emitters is persistently pursued for the application of organic light-emitting diodes(OLED)in full-colour display and solid-state lighting.Herein,we present a heptagonal intramolecular-lock strategy to design high-performance TADF emitters.As a proof-of-concept,a new type of tribenzotropone(TBP)acceptor has been designed and synthesized by a cascade decarboxylative cyclization of aryl oxoacetic acid derivative with biphenyl boronic acid.Compared with the unlocked benzophenone(BP)acceptor,the TBP acceptor has a highly twisted heptagonal geometry with moderate rigidity and flexibility,which enables a high-performance TADF emitter with a small single-triplet energy gap(ΔE_(ST))of 0.04 e V,a high photoluminescence quantum yield(Φ_(PL))of 99% and a large horizontal orientation factor(Θ_(//))of 84.0%.Consequently,highly efficient OLEDs with an external quantum efficiency as high as 33.8% are assembled,which is significantly higher than those of DPAC-BP with a highly rotatable BP acceptor(23.8%)as well as DPACFO with a rigid fluorenone(FO)acceptor(6.9%). 展开更多
关键词 organic light-emitting diodes medium-ring intramolecular-lock thermally activated delayed fluorescence molecular orientation
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One-shot synthesis of heavy-atom-modified carbazole-fused multi-resonance thermally activated delayed fluorescence materials
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作者 Jia-Jun Hu Jia-Qi Liang +3 位作者 Zhi-Ping Yan Hua-Xiu Ni Xiang-Ji Liao You-Xuan Zheng 《Science China Materials》 SCIE EI CAS CSCD 2024年第9期2789-2795,共7页
Efficient multi-resonance thermally activated delayed fluorescence(MR-TADF)materials hold significant potential for applications in organic light-emitting diodes(OLEDs)and ultra-high-definition displays.However,the st... Efficient multi-resonance thermally activated delayed fluorescence(MR-TADF)materials hold significant potential for applications in organic light-emitting diodes(OLEDs)and ultra-high-definition displays.However,the stringent synthesis conditions and low yields typically associated with these materials pose substantial challenges for their practical applications.In this study,we introduce an innovative strategy that involves peripheral modification with sulfur and selenium atoms for two materials,CFDBNS and CFDBNSe.This approach enables a directed one-shot borylation process,achieving synthesis yields of 66%and 25%,respectively,while also enhancing reverse intersystem crossing rates.Both emitters exhibit ultra-narrowband sky-blue emissions centered around 474 nm,with full width at half maximum(FWHM)values as narrow as 19 nm in dilute toluene solutions,along with high photoluminescence quantum yields of 98%and 99%in doped films,respectively.The OLEDs based on CFDBNS and CFDBNSe display sky-blue emissions with peaks at 476 and 477 nm and exceptionally slender FWHM values of 23 nm.Furthermore,the devices demonstrate remarkable performances,achieving maximum external quantum efficiencies of 24.1%and 27.2%.This work presents a novel and straightforward approach for the incorporation of heavy atoms,facilitating the rapid construction of efficient MR-TADF materials for OLEDs. 展开更多
关键词 one-shot synthesis multi-resonance thermally activated delayed fluorescence carbazole-fused dual-boron embedded framework ultra-narrowband emission organic light-emitting diode
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Chiral thermally activated delayed fluorescence materials for circularly polarized organic light-emitting diodes
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作者 Li Yuan Yi-Pin Zhang You-Xuan Zheng 《Science China Chemistry》 SCIE EI CAS CSCD 2024年第4期1097-1116,共20页
Chirality is an important natural characteristic of organic molecules,and chiral organic molecules have shown extensive application in areas such as pharmaceutical development and material science.Benefiting from the ... Chirality is an important natural characteristic of organic molecules,and chiral organic molecules have shown extensive application in areas such as pharmaceutical development and material science.Benefiting from the ability to achieve circularly polarized luminescence(CPL),chiral luminescent materials have shown potential applications in anti-glare display,optical communication and,3D display,etc.Due to the ability to harvest both singlet and triplet excitons by a fast reverse intersystem crossing process without involving noble metals,chiral thermally activated delayed fluorescence(TADF)materials with point chirality,axial chirality,planar chirality and helical chirality are regarded as the state-of-the-art materials for circularly polarized organic light-emitting diodes(CP-OLEDs).In recent years,the chiral TADF materials and CP-OLEDs have rapidly developed,but unfortunately,the dissymmetry factors(g)are far from the requirement of practical applications.The ideal emitters and devices should have both high efficiency and a g factor,or at least a balance between these two elements.This review gives an overview of recent progress in chiral TADF materials,with a particular focus on the chiral skeleton,CPL property and device performance.Furthermore,the molecular design concept,device structure and methods to improve the g factors of chiral materials and CP-OLEDs are also discussed. 展开更多
关键词 chiral thermally activated delayed fluorescence material chiral skeleton circularly polarized luminescence circularly polarized organic light-emitting diodes dissymmetry factor
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Chiral multiple-resonance thermally activated delayed fluorescence materials based on chiral spiro-axis skeleton for efficient circularly polarized electroluminescence
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作者 Shi-Quan Song Xiao Han +4 位作者 Zhong-Zhong Huo Ching-Fai Yip Xian-Fang Hong Meng-Ning Ding You-Xuan Zheng 《Science China Chemistry》 SCIE EI CAS CSCD 2024年第7期2257-2264,共8页
Chiral luminescence materials have potential applications in the field of three-dimensional displays due to their circularly polarized luminescence(CPL)characteristics.However,the further development of circularly pol... Chiral luminescence materials have potential applications in the field of three-dimensional displays due to their circularly polarized luminescence(CPL)characteristics.However,the further development of circularly polarized organic light-emitting diodes(CP-OLEDs)needs to meet the requirements of high efficiency,high color purity,low cost,and high dissymmetry factor(gPLor gEL),chiral multiple resonance thermally activated delayed fluorescence(MR-TADF)materials are considered as candidates in these aspects.Herein,based on a pair of chiral spirofluorene precursors,two pairs of high-performance chiral MR-TADF emitters((R/S)-p-Spiro-DtBuCzB and(R/S)-m-Spiro-DtBuCzB)are developed,which exhibit strong emissions peaking at 491 and 502 nm in toluene with full-width at half-maximum values of 25 and 33 nm,respectively.In addition,small singlet–triplet energy gaps of 0.15 and 0.10 eV with high absolute photoluminescence efficiencies of 95.0%and 96.7%are observed for p-Spiro-DtBuCzB and m-Spiro-DtBuCzB molecules,respectively.OLEDs based on p-Spiro-DtBuCzB and m-Spiro-DtBuCzB display high maximum external quantum efficiencies of 29.6%and 33.8%,respectively.Most importantly,CP-OLEDs present symmetric circularly polarized electroluminescence spectra with|gEL|factors of 3.36×10^(-4)and 7.66×10^(-4)for devices based on(R/S)-p-Spiro-DtBuCzB and(R/S)-m-Spiro-DtBuCzB enantiomers,respectively. 展开更多
关键词 chiral spiro-axis skeleton-based material multiple resonance thermally activated delayed fluorescence circularly polarized electroluminescence dissymmetry factor external quantum efficiency
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Molecular Conformational Isomerization:An Efficient Way to Design Novel Emitters with Dual-Thermally Activated Delayed Fluorescence Characteristics and Their Optoelectronic and Bioimaging Applications
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作者 Yi-Zhong Shi Ya-Fang Xiao +8 位作者 Hao Wu Shao-Li Zhang Xiao-Chun Fan Ye Tian Chang-Qing Ye Kai Wang Jia Yu Chun-Sing Lee Xiao-Hong Zhang 《CCS Chemistry》 CSCD 2024年第4期912-922,共11页
Single-molecule luminophores with dual-thermally activated delayed fluorescence(TADF)properties are receiving increasing attention.However,how to achieve these goals requires more in-depth studies.Herein,we demonstrat... Single-molecule luminophores with dual-thermally activated delayed fluorescence(TADF)properties are receiving increasing attention.However,how to achieve these goals requires more in-depth studies.Herein,we demonstrate a novel example emitter,10-(5-(2-(pyridin-3-yl)-[4,5′-bipyrimidin]-6-yl)pyridin-2-yl)-10Hphenoxazine(PmPy-PXZ),enabling dual-TADF properties due to its key feature of conformational isomerization.Introducing a pyridine bridge can greatly reduce the steric hindrance and facilitate dual-stable conformations in the ground state,where the quasi-axial(QA)forms predominate.Moreover,unlike previously reported TADF molecules with dual confirmations,both theoretical and experimental measurements show that not only the quasi-equatorial(QE)forms but also the QA forms exhibit distinct TADF characteristics,which can be attributed to an additional higher reverse intersystem crossing pathway.This is the first time that dual-TADF properties of single molecules have been achieved based on conformational isomerism.Its applications in“self-doping”organic light-emitting diode and biomedical imaging have further been investigated.All these results show the good potential of such dual-band TADF emitters based on molecular conformational isomerization. 展开更多
关键词 dual-thermally activated delayed fluorescence conformational isomerization organic light-emitting diode biomedical imaging SELF-DOPING
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Supramolecular Thermally Activated Delayed Fluorescence Materials via Through-Space Charge Transfer
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作者 Yuqian Wang Ruicong Feng +1 位作者 Yang Yu Qiao Song 《CCS Chemistry》 CSCD 2024年第5期1165-1173,共9页
Thermally activated delayed fluorescence(TADF)polymeric materials based on through-space charge transfer(TSCT)have emerged as a highly studied topic in recent years.However,the construction of TSCT TADF materials via ... Thermally activated delayed fluorescence(TADF)polymeric materials based on through-space charge transfer(TSCT)have emerged as a highly studied topic in recent years.However,the construction of TSCT TADF materials via a supramolecular approach is still a big challenge.In this work,we report the noncovalent synthesis of TSCT TADF materials using a cyclic peptide-based bottle-brushed supramolecular polymer as a scaffold.By bringing the TSCT donor and acceptor in close proximity in space using the supramolecular scaffold,distinctive TADF emission in both solution and solid states could be achieved.Furthermore,the TADF system could be utilized as a sensitizer to coassemble with fluorescence acceptors to build thermally assisted fluorescence systems,resulting in color-tunable delayed fluorescence with high efficiency and color purity.Our findings provide a facile yet effective approach to designing and fabricating TSCT TADF materials,which might hold great potential for applications in the fields of organic light-emitting diode,bioimaging,and sensing. 展开更多
关键词 supramolecular chemistry cyclic peptide thermally activated delayed fluorescence throughspace charge transfer thermally assisted fluorescence
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Bipolar Thermally Activated Delayed Fluorescence Emitter with Balanced Carrier Transport for High-Efficiency Nondoped Green Electroluminescent Devices
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作者 Yuchao Liu Zhagen Miao +5 位作者 Haikuo Gao Shian Ying Can Gao Shouke Yan Huanli Dong Zhongjie Ren 《CCS Chemistry》 CSCD 2024年第9期2346-2357,共12页
High-efficiency electroluminescent devices featuring simplified architecture have received considerable attention due to significant advantages in construction procedures and commercialized applications.However,there ... High-efficiency electroluminescent devices featuring simplified architecture have received considerable attention due to significant advantages in construction procedures and commercialized applications.However,there still remains a critical challenge with regard to the lack of organic semiconductors that simultaneously possess high luminescent efficiency and balanced carrier-transporting abilities.Herein,we design a thermally activated delayed fluorescence(TADF)emitter 4-(9,9-dimethyl-9,10-dihydroacridine)-4′-triphenylphosphineoxide-benzophenone(DMAC-BPTPO)by incorporating triphenylphosphine oxide into the donor–acceptor skeleton.The accessional electrontransporting moiety,rod-like dimer,and horizontally packing model synergistically enable DMAC-BP-TPO which possesses an excellent photoluminescence quantum yield of nearly 90%with a reverse intersystem crossing rate constant of 2.0×106 s−1,horizontal dipole ratio of 89%,and a balanced electron and hole mobilities with a small constrast ratio of 1.08.Eventually,simplified electroluminescent devices including organic lightemitting diodes(OLEDs)and organic light-emitting transistors(OLETs)incorporating DMAC-BP-TPO-based nondoped film are demonstrated due to their superior integrated optoelectronic properties along with preferable horizontal dipole orientation.A record-high external quantum efficiency value of 21.7%and 4.4%are finally achieved in the simplified nondoped OLED and OLET devices,which are among the highest values in the related research fields.This work provides a new avenue to develop a high-efficiency bipolar TADF emitter to advance the simplified electroluminescent devices. 展开更多
关键词 organic light-emitting diode organic lightemitting transistor BIPOLAR thermally activated delayed fluorescence nondoped active layer
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Thermally activated delayed fluorescence carbazole-triazine dendrimer with bulky substituents
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作者 Hiroki Ikebe Kohei Nakao +7 位作者 Eri Hisamura Minori Furukori Yasuo Nakayama Takuya Hosokai Minlang Yang Guanting Liu Takuma Yasuda Ken Albrecht 《Aggregate》 EI CAS 2024年第1期236-243,共8页
Carbazole-triazine dendrimers with a bulky terminal substituent were synthesized,and the thermally activated delayed fluorescence(TADF)property was investigated.Compared to unsubstituted carbazole dendrimers,dendrimer... Carbazole-triazine dendrimers with a bulky terminal substituent were synthesized,and the thermally activated delayed fluorescence(TADF)property was investigated.Compared to unsubstituted carbazole dendrimers,dendrimers with bulky terminal substituents showed comparable to better photoluminescence quantum yields(PLQY)in neat films.Phenylfluorene(PF)-substituted dendrimers showed the highest PLQY of 81%,a smallΔEst of 0.06 eV,and the fastest reverse intersystem crossing(RISC)rate of∼1×10^(5 )s^(−1) compared to other dendrimers.Phosphorescence measurements of dendrimers and dendrons(fragments)indicate that the close proximity of the triplet energy of phenylfluorene-substituted carbazole dendrons(^(3)LE)to that of phenylfluorene-substituted dendrimers(^(1)CT,^(3)CT)contributes to RISC promotion and improves TADF efficiency.Terminal modification fine-tunes the energy level and suppresses intermolecular interactions,and this study provides a guideline for designing efficient solution-processable and non-doped TADF materials. 展开更多
关键词 DENDRIMER OLED TADF 1 INTRODUCTION Thermally activated delayed materials which are inexpensive and highly efficient alternatives to fluorescent
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Green and Near-Infrared Dual-Mode Afterglow of Carbon Dots and Their Applications for Confidential Information Readout 被引量:9
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作者 Yuci Wang Kai Jiang +4 位作者 Jiaren Du Licheng Zheng Yike Li Zhongjun Li Hengwei Lin 《Nano-Micro Letters》 SCIE EI CAS CSCD 2021年第12期148-162,共15页
Near-infrared(NIR),particularly NIR-containing dual-/multimode afterglow,is very attractive in many fields of application,but it is still a great challenge to achieve such property of materials. Herein,we report a fac... Near-infrared(NIR),particularly NIR-containing dual-/multimode afterglow,is very attractive in many fields of application,but it is still a great challenge to achieve such property of materials. Herein,we report a facile method to prepare green and NIR dual-mode afterglow of carbon dots(CDs) through in situ embedding o-CDs(being prepared from o-phenylenediamine) into cyanuric acid(CA) matrix(named o-CDs@CA). Further studies reveal that the green and NIR afterglows of o-CDs@CA originate from thermal activated delayed fluorescence(TADF) and room temperature phosphorescence(RTP) of o-CDs,respectively. In addition,the formation of covalent bonds between o-CDs and CA,and the presence of multiple fixation and rigid e ects to the triplet states of o-CDs are confirmed to be critical for activating the observed dual-mode afterglow. Due to the shorter lifetime and insensitiveness to human vision of the NIR RTP of o-CDs@CA,it is completely covered by the green TADF during directly observing. The NIR RTP signal,however,can be readily captured if an optical filter(cut-o wavelength of 600 nm) being used. By utilizing these unique features,the applications of o-CDs@CA in anti-counterfeiting and information encryption have been demonstrated with great confidentiality. Finally,the as-developed method was confirmed to be applicable to many other kinds of CDs for achieving or enhancing their afterglow performances. 展开更多
关键词 Carbon dots Dual-mode afterglow Room temperature phosphorescence Thermal activated delayed fluorescence Information security
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Characterization of a Chinese KCNQ1 mutation (R259H) that shortens repolarization and causes short QT syndrome 2 被引量:5
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作者 Zhi-Juan WU Yun HUANG +6 位作者 Yi-Cheng FU Xiao-Jing ZHAO Chao ZHU Yu ZHANG Bin XU Qing-Lei ZHU Yang LI 《Journal of Geriatric Cardiology》 SCIE CAS CSCD 2015年第4期394-401,共8页
Objectives To evaluate the association between a KCNQ 1 mutation, R259H, and short QT syndrome (SQTS) and to explore the elec- trophysiological mechanisms underlying their association. Methods We performed genetic s... Objectives To evaluate the association between a KCNQ 1 mutation, R259H, and short QT syndrome (SQTS) and to explore the elec- trophysiological mechanisms underlying their association. Methods We performed genetic screening of SQTS genes in 25 probands and their family members (63 patients). We used direct sequencing to screen the exons and intron-exon boundaries of candidate genes that en- code ion channels which contribute to the repolarization of the ventricular action potential, including KCNQI, KCNH2, KCNE1, KCNE2, KCNJ2, CACNAlc, CACNB2b and CACNA2D1. In one of the 25 SQTS probands screened, we discovered a KCNQ1 mutation, R259H. We cloned R259H and transiently expressed it in HEK-293 cells; then, currents were recorded using whole cell patch clamp techniques. Results R259H-KCNQ 1 showed significantly increased current density, which was approximately 3-fold larger than that of wild type (WT) after a depolarizing pulse at 1 s. The steady state voltage dependence of the activation and inactivation did not show significant differences between the WT and R259H mutation (P 〉 0.05), whereas the time constant of deactivation was markedly prolonged in the mutant compared with the WT in terms of the test potentials, which indicated that the deactivation of R259H was markedly slower than that of the WT. These results suggested that the R259H mutation can effectively increase the slowly activated delayed rectifier potassium current (Irs) in phase 3 of the cardiac action potential, which may be an infrequent cause of QT interval shortening. Conclusions R259H is a gain-of-function muta- tion of the KCNQ1 channel that is responsible for SQTS2. This is the first time that the R259H mutation was detected in Chinese people. 展开更多
关键词 Ion channel KCNQ1 gene MUTATION Short QT syndrome Slowly activated delayed rectifier potassium current
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Enhancement of electroluminescent properties of organic optoelectronic integrated device by doping phosphorescent dye 被引量:1
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作者 雷疏影 钟建 +2 位作者 周殿力 朱方云 邓朝旭 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第11期434-440,共7页
Organic optoelectronic integrated devices(OIDs) with ultraviolet(UV) photodetectivity and different color emitting were constructed by using a thermally activated delayed fluorescence(TADF) material 4, 5-bis(ca... Organic optoelectronic integrated devices(OIDs) with ultraviolet(UV) photodetectivity and different color emitting were constructed by using a thermally activated delayed fluorescence(TADF) material 4, 5-bis(carbazol-9-yl)-1, 2-dicyanobenzene(2 CzPN) as host. The OIDs doping with typical red phosphorescent dye [tris(1-phenylisoquinoline)iridium(Ⅲ), Ir(piq)3], orange phosphorescent dye {bis[2-(4-tertbutylphenyl)benzothiazolato-N,C-(2')]iridium(acetylacetonate),(tbt)2 Ir(acac)}, and blue phosphorescent dye [bis(2, 4-di-fluorophenylpyridinato)-tetrakis(1-pyrazolyl)borate iridium(Ⅲ), FIr6] were investigated and compared. The(tbt)2 Ir(acac)-doped orange device showed better performance than those of red and blue devices, which was ascribed to more effective energy transfer. Meanwhile, at a low dopant concentration of 3 wt.%, the(tbt)2 Ir(acac)-doped OIDs showed the maximum luminance, current efficiency, power efficiency of 70786 cd/m^2, 39.55 cd/A, and 23.92 lm/W, respectively, and a decent detectivity of 1.07 × 10^11 Jones at a bias of -2 V under the UV-350 nm illumination. This work may arouse widespread interest in constructing high efficiency and luminance OIDs based on doping phosphorescent dye. 展开更多
关键词 organic optoelectronic integrated device thermally activated delayed fluorescence host phosphorescent dye high luminance
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