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Efficient soluble deep blue electroluminescent dianthracenylphenylene emitters with CIE y(y≤0.08) based on triplet-triplet annihilation

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Science Bulletin 2019年第11期64卷 774-781页

作者： Ling Peng Jing-Wen Yao Mei Wang Lin-Ye Wang Xiao-Lan Huang Xin-Feng Wei Dong-Ge Ma Yong Cao Xu-Hui Zhu State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices South China University of Technology (SCUT)

It has been challenging to develop deep blue organic molecular fluorescent emitters with CIE y(y≤0.08)based on triplet-triplet annihilation(TTA). Here, we report facilely available dianthracenylphenylenebased emitters, which have a 3,5-di(4-t-butylphenyl)phenyl moiety at the one end and 4-cyanophenyl or 3-pyridyl at the other end, respectively. Both fluorophores show a high glass transition temperature of over 220℃ with a thermal decomposition temperature of over 430℃ at an initial weight loss of1%. The preliminary characterizations of the organic light-emitting diodes(OLEDs) that utilized these nondoped emitters provided high EQEs of 4.6%à5.9% with CIE coordinates(0.15, 0.07–0.08). The analysis of the EL transient decay revealed that TTA contributed to the observed performance. The results show that the new emitters are attractive as a potential TTA-based host to afford stable deep blue fluorescent OLEDs.

关键词： Anthracene Deep blue emission Fluorescence Organic light-emitting diodes Triplet-triplet annihilation

Interaction behaviours of solitoffs:fission, fusion, reconnection and annihilation

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Chinese Physics B 2010年第10期19卷 25-33页

作者：李军民梁祖峰唐晓艳 Department of Physics Shanghai Jiao Tong University Department of Physics Hangzhou Normal University

The interactions between solitoffs are extensively investigated. Besides the known solitoff fission and fusion interac- tions, two new types of solitoff interactions are discovered, named the solitoff reconnection and the solitoff annihilation. Taking the asymmetric Nizhnik-Novikov Veselov equation as an illustrative system, five types of solitoff interactions are graphically revealed on the basis of the analytical solution obtained by the modified tanh function expansion method.

关键词： fission fusion reconnection annihilation

Effects of thermal aging on Fe ion-irradiated Fe–0.6%Cu alloy investigated by positron annihilation

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Nuclear Science and Techniques 2017年第2期28卷 8-11页

作者： Yuan-Chao Hu Xing-Zhong Cao Peng Zhang Hidetsugu Tsuchida Qiu Xu Shuo-Xue Jin Er-Yang Lu Yu-Xiao Li Run-Sheng Yu Bao-Yi Wang Long Wei Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China College of Physical Engineering Zhengzhou UniversityZhengzhou 450001 China Quantum Science and Engineering Center Kyoto UniversityUji 6110011 Japan Research Reactor Institute Kyoto UniversityOsaka 5900494 Japan

Thermal aging effects on surface of 2.5 Me V Fe ion-irradiated Fe–0.6%Cu alloy were investigated using positron annihilation techniques. The samples were irradiated at 573 K to a dose of 0.1 dpa. Their thermal aging was performed at 573 K for 5, 50 and 100 h. From the results of Doppler broadening measurement, an obvious trough could be seen in near-surface region from the S parameters and inflection point form at S–W curves. This indicates changes in the annihilation mechanism of positrons in surface region after thermal aging. Coincident Doppler broadening indicates that the density of Cu precipitates in the thermal aged samples decreased, due to recovery of the vacancies.

关键词： Fe–Cu alloy Positron annihilation Irradiation Thermal aging

Direct Detection of Dark Matter with Resonant annihilation

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Communications in Theoretical Physics 2015年第7期64卷 119-126页

作者：李博周宇峰 State Key Laboratory of Theoretical Physics Kavli Institute for Theoretical Physics China Institute of Theoretical Physics Chinese Academy of Sciences

In the scenario where the dark matter(DM) particles χχˉ pair annihilate through a resonance particle R,the constraint from DM relic density makes the corresponding cross section for DM-nuclei elastic scattering extremely small, and can be below the neutrino background induced by the coherent neutrino-nuclei scattering, which makes the DM particle beyond the reach of the conventional DM direct detection experiments. We present an improved analytical calculation of the DM relic density in the case of resonant DM annihilation for s- and p-wave cases and invesitgate the condition for the DM-nuclei scattering cross section to be above the neutrino background. We show that in Higgs-portal type models, for DM particles with s-wave annihilation, the spin-independent DM-nucleus scattering cross section is proportional to ΓR/mR, the ratio of the decay width and the mass of R. For a typical DM particle mass ～ 50 Ge V,the condition leads to ΓR/mR≥O(10-4). In p-wave annihilation case, the spin-independent scattering cross section is insensitive to ΓR/mR, and is always above the neutrino background, as long as the DM particle is lighter than the top quark. The real singlet DM model is discussed as a concrete example.

关键词： resonant annihilation relic density neutrino backg

Towards Determining Kinetics of annihilation Electrogenerated Chemiluminescence by Concentration-Dependent Luminescent Intensity

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Journal of Analysis and Testing 2019年第2期3卷 160-165页

作者： Klaus Mathwig Neso Sojic Groningen Research Institute of Pharmacy Pharmaceutical AnalysisUniversity of GroningenP.O.Box 1969700 AG GroningenThe Netherlands Bordeaux INP Univ.BordeauxCNRSUMR 5255Site ENSCBP33607 PessacFrance Department of Chemistry South Ural State UniversityChelyabinsk 454080Russian Federation

In ion-annihilation electrochemiluminescence(ECL),luminophore ions are generated by oxidation as well as reduction at electrodes surfaces,and subsequently recombine into an electronically excited state,which emits light.The intensity of the emitted light is often limited by the kinetic rate of recombination of the luminophore ion species.Recombination or annihilation rates are high ranging up to approximately 10^(10) M^(−1) s^(−1) and can be difficult to determine using scanning electrochemical microscopy or high-frequency oscillations of an electrode potential.Here,we propose determining annihilation kinetics by measuring the relative change of the emitted light intensity as a function of luminophore concentration.Using finite element simulations of annihilation ECL in a geometry of two closely spaced electrodes biased at constant potentials,we show that,with increasing concentrations,luminescence intensity crosses over from a quadratic dependence on concentration to a linear regime-depending on the rate of annihilation.Our numerical results are applicable to scanning electrochemical microscopy as well as nanofluidic electrochemical devices to determine fast ion-annihilation kinetics.

关键词： Electrogenerated chemiluminescence annihilation Mechanisms Ion-annihilation kinetics Redox cycling Nanogap transducer

Computer Simulation on Kinetics of Primary Processes in Photosynthesis Ⅰ——Mechanism of Exciton annihilation of Excited State Decay in Phycobiliproteins

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Science China Chemistry 1993年第10期36卷 1186-1197页

作者：赵井泉朱晋昌蒋丽金 Institute of Photographic Chemistry Academia Sinica Beijing 100101 PRC

A discrete model was used for studying the effects of exciton annihilation on the decay behavior of the excited state in phycobiliprotein super-molecules. The simulation shows: The more the chromophores are and the higher the excitation beam intensity is, the more susceptible to annihilation is a system; annihilation starts to occur at 1013 photons/cm2 and becomes saturated at about 1015—1016 photons/cm2 with the parameters used in the current work. Whether the exciton annihilation occurs or not should not be simply judged from whether the decaying data could be fitted with a mono-exponential function. The quantum yield of fluorescence decreases synchronously with the increase of exciton annihilation extent. The so called "safety intensity" has significance only in special cases. In fact, annihilation extent is dependent not only on the pulse intensity but also on the width of the pulse, the optical cross section of a chromophore as well as the light absorption coefficient of a system.

关键词： phycobiliprotein exciton annihilation Monte Carlo computer simulation.

The behavior of 3d electrons and defects in TiAl-based alloys containing V and Cu studied by positron annihilation

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Science China(Physics,Mechanics & Astronomy) 2008年第9期51卷 1221-1228页

作者： DENG Wen CHEN ZhenYing JIANG HaiFeng SUN ShunPing ZHU YingYing HUANG YuYang College of Physics Science and Technology Guangxi UniversityNanning 530004China Department of Physics and Chemistry Henan Polytechnic UniversityJiaozuo 454000China International Centre for Materials Physics Chinese Academy of SciencesShenyang 110016China

Information of defects and 3d electrons in transition metals (Ti,V,Cu) and TiAl-based alloys (Ti50Al50,Ti50Al48V2,Ti50Al48Cu2) can be extracted from the positron lifetime and coincidence Doppler broadening spectra. The results show that the 3d electron signals for the transition metals Ti,V and Cu increase with the number of 3d electrons. The 3d electron signal and the electron density for binary TiAl alloy are relatively low due to the (Ti)3d-(Al)3p interactions. The addition of V and Cu atoms to TiAl alloy leads to the increase in the electron densities in bulk and the defects on grain boundaries simultaneously,as well as the enhancement of the 3d electron signal. The 3d electron signal in the spectrum of Ti50Al48Cu2 alloy is higher than that of Ti50Al48V2 alloy.

关键词： TiAl alloy 3d electron defect positron annihilation

Pure annihilation type D→PP(V) decays in the perturbative QCD approach

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Chinese Physics C 2013年第9期37卷 1-5页

作者：邹芝田李承吕才典 Institute of High Energy Physics and Theoretical Physics Center for Science Facilities Chinese Academy of Sciences

The annihilation type diagrams are difficult to calculate in any kind of model or method. Encouraged by the successful calculation of pure annihilation type B decays in the perturbative QCD factorization approach, we calculate the pure annihilation type D→ PP（V） decays in the perturbative QCD approach based on the kw factorization. Although the expansion parameter 1lind is not very small, our leading order numerical results agree with the existing experimental data for most channels. We expect more accurate observation from experiments, which can help us learn about the dynamics of D meson weak decays.

关键词： D meson perturbative QCD annihilation

EFFECT OF POLYMERIZATION DEGREE ON MICROSTRUCTURE OF POLYETHYLENE GLYCOL STUDIED BY POSITRON annihilation

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Nuclear Science and Techniques 1993年第4期4卷 213-216页

作者：王采林王波李世清王少阶姚宁 Wuhan University Wuhan 430072 China Hubei Provincial Institute of Chemistry Research Wuhan 430074 China

Positron lifetimes in polyethylene glycol (PEG) polymer have been measured as a function of polymerization degree N (N = 25 - 500). It is observed that all the positron parameters are strongly dependent on N when N≤250, and then tend to constant levels when N≥250. The variations of the longest-lived component (I3,τ3) show that the size of free- volume holes has a minimum at N - 100 and the hole concentration decreases with N. These trends may be due to the variations in crystallinity, the chain ends, entanglements and the Van der Waals interaction between segments. The variations of the second component (I2,τ2) with N reflect the changes of defect properties in crystalline regions of PEG.

关键词： Potitron annihilation Polyethylene glycol Free-volume hole Defect