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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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CCS Chemistry 2024年第9期6卷 2346-2357页

作者： Yuchao Liu Zhagen Miao Haikuo Gao Shian Ying Can Gao shouke yan Huanli Dong Zhongjie Ren Key Laboratory of Rubber-Plastics Ministry of Education/Shandong Provincial Key Laboratory of Rubber-PlasticsSchool of Polymer Science and EngineeringQingdao University of Science and TechnologyQingdao 266042 National Laboratory for Molecular Sciences Key Laboratory of Organic SolidsInstitute of ChemistryChinese Academy of SciencesBeijing 100190 Department of Chemistry University of Chinese Academy of SciencesBeijing 100049 Shandong Engineering Research Center of Aeronautical Materials and Devices College of Aeronautical EngineeringBinzhou UniversityBinzhou 251900 State Key Laboratory of Chemical Resource Engineering College of Materials Science and EngineeringBeijing University of Chemical TechnologyBeijing 100029

High-efficiency electroluminescent devices featuring simplified architecture have received considerable attention due to significant advantages in construction procedures and commercialized ***,there still remains a critical challenge with regard to the lack of organic semiconductors that simultaneously possess high luminescent efficiency and balanced carrier-transporting ***,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 *** 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 ***,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 *** work provides a new avenue to develop a high-efficiency bipolar TADF emitter to advance the simplified electroluminescent devices.

关键词： organic light-emitting diode organic lightemitting transistor bipolar thermally activated delayed fluorescence nondoped active layer

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Structural variation of melt-crystallized PTT during the heating process revealed by FTIR and SAXS

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Chinese Science Bulletin 2013年第3期58卷 328-335页

作者： CHEN Zhen yan shouke Institute of Chemistry Chinese Academy of Sciences

Time-resolved FTIR,WAXD/SAXS and DSC have been used to investigate the structural variation of non-isothermally crystallized poly(trimethylene terephthalate)(PTT) during the heating *** three-phase model:the lamellar phase,the mobile amorphous phase(MAP) and the rigid amorphous phase(RAP) between lamellae is suggested to describe the structure of meltcrystallized *** to FTIR results,the conformation of RAP in the constrained state is different from that of *** increased content of amorphous phase in the temperature range from 120 to 192℃ is ascribed to the relaxation of RAP,rather than the melting of defective *** the PTT is heated to a temperature above 192℃,the recrystallization/crystal perfection of original defective lamellae occurs without a pre-melting process,which leads to an increase in lamellar thickness and probably connects two adjacent lamellar *** is responsible for an increase in crystallinity as well as a higher major melting temperature.

关键词： FTIR 结构变化加热过程 SAXS PTT 熔融结晶广角X射线衍射无定形结构

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Structure characterization of melt drawn polyethylene ultrathin films

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Chinese Science Bulletin 2006年第23期51卷 2844-2850页

作者： yan Chao ZHANG Jianming SHEN Deyan yan shouke State Key Laboratory of Polymer Physics and Chemistry Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China

Highly oriented ultrathin polyethylene (PE) films were prepared by a melt-draw technique. Transmission electron microscopy study on the obtained ultrathin films indicates that the melt drawn PE thin films consist of highly oriented edge-on lamellae aligned perpendicular to the drawing direction. Electron diffraction confirms that the PE chains in crystal-line phase are highly oriented in film plane along the drawing direction, while only a random orientation of the crystallographic a-and b-axes can be described through electron diffraction. The IR results on the melt-drawn ultrathin PE films demonstrate that the PE molecular chains in both crystalline and amorphous phases of the melt drawn thin films are well oriented along the drawing direction. Moreover, the IR results indicate that in the crystalline phase, the crystallographic b-axis tend to lie in the thin film plane, while in the amorphous phase, the skeleton plane of some local chains prefers to parallel the film plane. The alignment of b-axis of PE crystals in ultrathin films originates from the fact that the b-axis is the fastest growth direction of the PE crystals.

关键词：超薄PE薄膜定向红外线光谱学电子显微术

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A study on the double melting behavior of poly(trimethylene terephthalate)

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Chinese Science Bulletin 2008年第14期53卷 2145-2155页

作者： ZENG Wei LI Huihui LIU TianXi yan shouke Beijing National Laboratory for Molecular Sciences and State Key Laboratory of Polymer Physics and Chemistry Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China Department of Macromolecular Science Fudan University Shanghai 200230 China

Double melting behavior of poly(trimethylene terephthalate) (PTT) was studied in detail by means of differential scanning calorimetry (DSC) and optical microscopy. The results indicate that the low-temperature melting peak of PTT at ca. 218℃ for the samples crystallized isothermally at 203℃ is associated with the melting of crystals produced by secondary crystallization, while the high-temperature melting peak of it at about 227℃ is related to the melting of the crystals produced by primary crystallization. The results further demonstrate that the PTT crystals growing non-isothermally during cooling process are thermodynamically unstable and can undergo structure reorganization during the DSC heating scan. The reorganized crystals melt at temperature higher than the crystals produced by secondary crystallization at 203 ℃. Consequently, for the non-fully crystallized samples, the crystals grown during cooling also exhibit contribution to the high-temperature melting peak.

关键词：聚乙烯双熔技术结晶作用化学分析

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A comparison study on the melt crystallization kinetics of long chain branched and linear isotactic polypropylenes

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Chinese Science Bulletin 2008年第2期53卷 188-197页

作者： ZENG Wei LIU JiChun ZHOU JunFeng DONG JinYong yan shouke Beijing National Laboratory for Molecular Sciences and Joint Laboratory of Polymer Science and Materials Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China State Key Laboratory of Polymer Physics and Chemistry and Key Laboratory of Engineering Plastics Chinese Academy of Sciences Beijing 100080 China Key Laboratory of Polymer Science and Nanotechnology College of Chemical Engineering and Pharmaceutics Henan University of Science and Technology Luoyang 471003 China

The isothermal and non-isothermal crystallization kinetics of LCBPP and linear-iPP was investigated by optical microscopy and differential scanning calorimetry (DSC). The optical microscopy results in the isothermal crystallization process show that the crystals of LCBPP grow slower than the crystals of the linear-iPP. This originates from the low chain mobility, or in other words, the lower chain diffusion rate of LCBPP due to the existence of long side chains. The DSC results in the isothermal crystallization process show that the LCBPP exhibits, however, a higher overall crystallization rate with respect to the linear-iPP. This is related to the higher nucleation ability of LCBPP since the isothermal crystallization process of both LCBPP and linear-iPP are nucleation-dominated. Avrami analysis indicates that the nucleation nature and crystal growth manner of LCBPP and linear-iPP are about the same. The analy- ses of the non-isothermal crystallization processes indicate an increment in crystallization rate with increasing cooling rate. But at any cooling rate, the linear-iPP crystallizes more quickly than the LCBPP. This implies that the non-isothermal crystallization processes of LCBPP and linear-iPP are diffu- sion-dominated, in which the lower chain diffusion rate of LCBPP results in the slower crystallization of it.

关键词：聚丙烯长链分岔线性全规聚丙烯结晶动力学

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Effect of crystallization temperature and propylene sequence length on the crystalline structure of propylene-ethylene random copolymers

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Chinese Science Bulletin 2008年第12期53卷 1804-1812页

作者： GOU QingQiang LI HuiHui YU ZhenQiang CHEN ErQiang ZHANG YuDong yan shouke Beijing National Laboratory for Molecular Sciences and State Key Laboratory of Polymer Physics and Chemistry Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China Department of Polymer Science School of Chemistry Peking University Beijing 100871 China Beijing Research Institute of Chemical Industry SINOPEC Beijing 100013 China candidate of Graduate University of Chinese Academy of Sciences Beijing100039 China

Crystallization behavior and resultant crystalline structure of a series of temperature-rising elu-tion-fractionated specimen of a Ziegler-Natta catalyst-synthesized propylene-ethylene random co-polymer were studied by DSC, WAXD and AFM. The experimental results indicate that both crystalliza-tion temperature and propylene sequence length exhibit great influence on the crystallization behavior and crystalline structure of the copolymer. It was found that the ethylene co-monomers acting as point defects inserted into the polypropylene chains play an important role in the formation of γ-iPP. As the co-monomer content increases, the crystallizable sequence length of iPP decreases, which produces an appropriate condition for its γ crystallization. At the same time, the existence of chain defects leads to a lower crystallinity of the copolymer and imperfection of the resultant crystals. For each individual sample with certain propylene sequence length or ethylene content, the increment of γ-iPP crystal content with increasing crystallization temperature demonstrates that higher crystallization tempera-ture is in favor of the γ-iPP crystallization. Pure γ-iPP crystals have been got in samples with propylene sequence length lower than 21 under suitable crystallization conditions.

关键词：结晶温度晶体乙烯共聚物

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电介质聚丙烯薄膜晶体结构研究

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电力电容器与无功补偿 2024年第1期45卷 56-62页

作者：孙朦龙厚尹柏潇闫寿科孙晓丽北京化工大学化工资源有效利用国家重点实验室北京100029 青岛科技大学橡塑材料与工程教育部重点实验室山东青岛266042

电介质聚丙烯薄膜是干式直流电容器的核心,是新能源发电和柔性直流输电的“心脏”,直接影响电能变换的质量与安全。聚丙烯薄膜的晶体结构对电容器的性能起着决定性的作用。本文对三种聚丙烯(PP)粒料经流延双轴拉伸制备成的电容器用电介... 详细信息

电介质聚丙烯薄膜是干式直流电容器的核心,是新能源发电和柔性直流输电的“心脏”,直接影响电能变换的质量与安全。聚丙烯薄膜的晶体结构对电容器的性能起着决定性的作用。本文对三种聚丙烯(PP)粒料经流延双轴拉伸制备成的电容器用电介质薄膜(BOPP)的晶体结构采用广角X-射线衍射、傅里叶变换红外光谱、差示量热扫描等表征法进行了研究。表征结果发现,三种BOPP电介质薄膜均由α相构成,但其结晶度、熔点以及不同晶面方向上的晶粒尺寸存在较大差别。其中,基于北欧粒料的电介质薄膜熔点最低(169℃),结晶度最高(59.8%),且在[060]方向上的晶粒尺寸最大。红外光谱结果表明,基于北欧粒料的BOPP试样中,序列长度为n=14的31螺旋链段最多。通过对BOPP薄膜熔融重结晶后试样的研究发现,三种粒料的结晶度几乎无差别(~53%),但北欧PP粒料的非等温结晶温度最高(119℃),且在熔融过程出现明显β相熔融峰。中石化PP粒料的非等温结晶温度最低,较北欧PP粒料低3℃。

关键词：聚丙烯电介质薄膜结晶结构熔融

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Constructing an efficient deep-blue TADF emitter by host-guest interactions towards solution-processed OLEDs with narrowband emission

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Science China Chemistry 2023年第3期66卷 826-836页

作者： yanchao Xie Lei Hua Zhi Wang Yuerong Liu Shian Ying Yuchao Liu Zhongjie Ren shouke yan Department Key Laboratory of Rubber-Plastics Ministry of Education/Shandong Provincial Key Laboratory of Rubber-PlasticsSchool of Polymer Science and EngineeringQingdao University of Science&TechnologyQingdao 266042China State Key Laboratory of Chemical Resource Engineering College of Materials Science and EngineeringBeijing University of Chemical TechnologyBeijing 100029China

High-efficiency thermally activated delayed fluorescence(TADF) emitters and corresponding well-designed solution-processed organic light emitting diodes(OLEDs) are presently attractive due to their potential for exploiting large-area flexible displays. In this context, we innovatively integrate 2,12-di-tert-butyl-5,9-dioxa-13b-boronaphtho [3,2,1] anthracene as the acceptor with 3,6-bis(3,6-di-tert-butylcarbazol-N-yl) carbazole as the donor to construct a rigid deep-blue emitter, TB-3t BuCz, which exhibits a narrow emission with full-width-at-half-maximum(FWHM) of 46 nm. TB-3t BuCz itself dispalys no TADF characteristics both in solution or in pure film states. However, the significant TADF behavior can be observed when TB-3t BuCz is doped with 2,6-DCzPPy host due to the formation of exciplex-like species in 2,6-DCzPPy/TB-3t BuCz system. It is also found that the discernible spin-flip of triplet excitons is feasible when the S1/T1states of the formed exciplex stay slightly lower than S1 and T1states of TB-3t BuCz for the other host/TB-3t BuCz systems. Eventually, thanks to the synergetic effect of rigid structure and favorable photophysical properties of TB-3t BuCz, the solution-processed OLEDs based on 2,6-DCzPPy/TB-3t BuCz as emitting layer has achieved the significantly improved external quantum efficiency(EQE) of 14.6% with suppressed efficiency *** CIE1931 coordinate of(0.158, 0.052) is typically in deep-blue region. Note that, this EQE value is among the highest echelon of solution-processed OLEDs with deep-blue emission by utilizing boron-containing TADF emitters.

关键词： thermally activated delayed fluorescence oxygen-bridged cyclized boron host-guest interactions solution-processed OLEDs narrowband deep-blue emission

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Enhance the performance of polymer solar cells via extension of the flanking end groups of fused ring acceptors

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Science China Chemistry 2018年第10期61卷 1320-1327页

作者： Shiyu Feng Danyang Ma Liangliang Wu Yahui Liu Cai'e Zhang Xinjun Xu Xuebo Chen shouke yan Zhishan Bo Key Laboratory of Energy Conversion and Storage Materials College of Chemistry Key Laboratory of Theoretical and Computational Photochemistry Ministry of Education Beijing Normal University State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical Technology

Two new fused ring electron acceptors(FREAs)IDT-IC-T and IDT-IC-B with thienyl or phenyl substituents at the terminal INCN unit are *** calculations indicate that the two acceptors dominantly favor an intermolecularπ-πstacking between the flanking terminal *** twist angle between the aryl substituent and INCN unit has a significant influence on theπ-πstacking distance of terminal ***-IC-T with a smaller twist angle has a shorterπ-πstacking distance than that of IDT-IC-B with a larger twist *** addition,extending the conjugation also affects the blend film ***-IC-T and IDT-IC-B based photoactive films show appropriate nanoscale phase separations;whereas,blend films based on the parent compound IDT-IC show large-size acceptor *** expected,PBDB-T:IDT-IC-T blend films show higher and more balanced electron and hole ***,these two acceptors present a good charge-transport connectivity arising from the extended conjugation and the increased intermolecular ***,IDT-IC-T demonstrates the highest electron mobility(1.47×10^(-4)cm^2V^(-1)s^(-1))and the best power conversion efficiency(PCE)of 9.43%.As for IDT-IC,which only shows an electron mobility of 7.33×10^(-5)cm^2V^(-1)s^(-1)and a PCE of 5.82%.These findings provide a facile and effective way to improve the photovoltaic performance.

关键词： non-fullerene extended end groups high charge mobility polymer solar cells

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Realizing External Quantum Efficiency over 25% with Low Efficiency Roll-Off in Polymer-Based Light-Emitting Diodes Synergistically Utilizing Intramolecular Sensitization and Bipolar Thermally Activated Delayed Fluorescence Monomer

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CCS Chemistry 2023年第4期5卷 1005-1017页

作者： Yuchao Liu yanchao Xie Lei Hua Xingwen Tong Shian Ying Zhongjie Ren shouke yan Key Laboratory of Rubber-Plastics Ministry of Education/Shandong Provincial Key Laboratory of Rubber-PlasticsQingdao University of Science and TechnologyQingdao 266042 State Key Laboratory of Chemical Resource Engineering College of Materials Science and EngineeringBeijing University of Chemical TechnologyBeijing 100029

Since polymer-based light-emitting diodes(PLEDs)arewellsuited building blocks for large-area and low-cost flexible display equipment,state-of-the-art thermally activated delayed fluorescence(TADF)PLEDs are in high *** respond to this demand,light-emitting TADF units have initially been modified with electron-transporting units to balance the carrier transport of regiorandom TADF polymers,and simultaneously,an intramolecular sensitizing strategy has also been employed by covalently incorporating TADF sensitizers with light-emitting TADF units and hosts in conjugated polymers to accelerate the spin-flip of triplet *** photophysical properties have been achieved by a rational regulation of the proportions of each component,achieving a photoluminescence quantumyield of 90%,an extremely high rate of reverse intersystem crossing of 3×106 s−1,and a relatively low nonradiative decay rate of around 105 s−*** a result,the solutionprocessed PLEDs can attain an external quantum efficiency(EQE)value of 25.4%with emission peaks of around 550 nm,representing record-high performance for *** efficiency roll-off can also be significantly suppressed,maintaining an EQE value of 24.2%at 1000 cd/m2 with ideal efficiency roll-off of lower than 5%.Encouragingly,this work provides a valid strategy to tackle the imperative need for PLEDs with high EQE and low efficiency roll-off.

关键词： thermally activated delayed fluorescence polymer light-emitting diodes intramolecular sensitizing strategy balanced carrier transports low efficiency roll-off

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