Novel tri-carbazole modified fluorene host material for highly efficient solution-processed blue and green electrophosphorescent devices

A series of novel solution-processable small-molecule host materials: 2DPF-TCz, 2SBF-TCz, 27DPF-TCz, and 27SBF-TCz comprising a fluorene monomer as the rigid core and tri-carbazole as the periphery have been designed and synthesized, and their optical, electrochemical, and thermal properties have been fully characterized. The host materials exhibit high glass-transition temperatures (231–310 °C) and high triplet energy levels (2.61–2.73 eV). High-quality amorphous thin films can be obtained by spin-coating the host materials from solutions. It is found that the HOMO level of the host materials can be tuned by linking the tri-carbazole unit to the 2,7 positions of the fluorine core, resulting in appropriate HOMO energy levels (−5.36 to −5.23 eV) for improved hole-injection in the device. Solution-processed blue and green electrophosphorescent devices bases on the developed host materials exhibit high efficiencies of 21.2 and 34.8 cd A⁻¹, respectively.     

硫代多联吡啶铂(Ⅱ)配合物的合成、性质及在光催化制氢中的应用

合成了2个新配体4-(4-硫代乙酸)甲苯基-6-苯基-2,2’-联吡啶HC^N^N(PhCH2SCOCH3)(L3)和6-(4-硫代乙酸)甲苯基-2,2’-联吡啶HC^N^N(CH2SCOCH3)(L5)及其发光的铂(Ⅱ)配合物ClPtC^N^N(PhCH2SCOCH3)(C3)和ClPtC^N^N(CH2SCOCH3)(C5).通过1H NMR谱和质谱对它们的结构进行了表征,采用X射线单晶衍射分析确定了C3的晶体结构.利用紫外-可见吸收光谱、发射光谱及激发态寿命测定研究了它们的光物理性质和电化学性质,以及配合物作为光敏剂在光催化制氢中的应用.通过系列配合物产氢效率的比较,揭示了它们的产氢效率和激发态寿命的关系.     

Counterflow isotachophoresis in a monolithic column

This study describes stationary counterflow isotachophoresis (ITP) in a poly(acrylamide‐co‐N,N′‐methylenebisacrylamide) monolithic column as a means for improving ITP processing capacity and reducing dispersion. The flow profile in the monolith was predicted using COMSOL's Brinkman Equation application mode, which revealed that the flow profile was mainly determined by monolith permeability. As monolith permeability decreases, the flow profile changes from a parabolic shape to a plug shape. An experimental monolithic column was prepared in a fused‐silica capillary using an ultraviolet‐initiated polymerization method. A monolithic column made from 8% (wt.) monomer was chosen for the stationary counterflow ITP experiments. Counterflow ITP in the monolithic column showed undistorted analyte zones with significantly reduced dispersion compared to the severe dispersion observed in an open capillary. Particularly, for r‐phycoerythrin focused by counterflow ITP, its zone width in the monolithic column was only one‐third that observed in an open capillary. These experiments demonstrate that stationary counterflow ITP in monoliths can be a robust and practical electrofocusing method.     

Effect of Axial Ligands on the Molecular Configurations,Stability, Reactivity,and Photodynamic Activities of Silicon Phthalocyanines

To demonstrate the effect of axial ligands on the structure–activity relationship, a series of axially substituted silicon phthalocyanines (SiPcs) have been synthesized with changes to the axial ligands. The reactivity of the axial ligand upon shielding by the phthalocyanine ring current, along with their stability, photophysical, and photodynamic therapy (PDT) activities were compared and evaluated for the first time. As revealed by single‐crystal XRD analysis, rotation of the axial ? OMe ligands was observed in SiPc 3 , which resulted in two molecular configurations coexisting synchronously in both the solid and solution states and causing a split of the phthalocyanine α protons in the ¹H NMR spectra that is significantly different from all SiPcs reported so far. The remarkable photostability, good singlet oxygen quantum yield, and efficient in vitro photodynamic activity synergistically show that compound 3 is one of the most promising photosensitizers for PDT.     

铀酰与羧酸和肟基类配体相互作用的理论研究

深入了解各种功能基团与铀酰离子的络合行为有助于设计和开发高效海水提铀吸附剂. 本工作通过密度泛函理论(DFT)方法系统地研究了两种典型铀酰络合配体吡啶-2,6-二羧酸(H₂DPA)和戊二酰偕亚胺二肟(H₂A)与铀酰离子及碳酸根离子形成的配合物的结构、成键性质以及热力学稳定性. 研究结果表明, 所有配合物中, 配体与铀酰离子之间具有不同强度的共价相互作用. 由于H₂A配位时发生了质子重排, 而且配体的解离能较高, 使其更难与[UO₂(CO₃)₃]^4-发生取代反应, 因此H₂DPA配体是海水提铀中一种潜在的有效配体. 本工作的相关研究结果为海水提铀中高效吸附基团的设计和开发提供了理论线索.     

Novel superabsorbent polymer composites based on α-cellulose and modified zeolite: synthesis,characterization, water absorbency and water retention capacity

Cellulose - Most superabsorbent polymers (SAPs) are prepared based on synthetic polymers (from petroleum resources), making them costly, nondegradable, and not ecofriendly. To overcome these...     

Generalized Fourth-Order Decompositions of Imaginary Time Path Integral: Implications of the Harmonic Oscillator

The imaginary time path integral formalism offers a powerful numerical tool for simulating thermodynamic properties of realistic systems. We show that, when second-order and fourth-order decompositions are employed, they share a remarkable unified analytic form for the partition function of the harmonic oscillator. We are then able to obtain the expression of the thermodynamic property and the leading error terms as well. In order to obtain reasonably optimal values of the free parameters in the generalized symmetric fourth-order decomposition scheme, we eliminate the leading error terms to achieve the accuracy of desired order for the thermodynamic property of the harmonic system. Such a strategy leads to an efficient fourth-order decomposition that produces third-order accurate thermodynamic properties for general systems.     

Effective strategy for polymer synthesis: multicomponent reactions and click polymerization

The rational selection of organic reactions in polymer synthesis is an important research content of polymer science. In recent years, multicomponent reaction as an efficient and green synthesis method has attracted the wide attention of researchers, injecting new and powerful vitality into the field of polymer synthesis. In the study of multicomponent reaction, researchers found the intersection of multicomponent reaction and click chemistry and put forward the concept of Multicomponent Click Reaction (MCR-Click), which is a kind of Multicomponent Reaction with high activity, atomic economy, and some green chemical properties. The application of MCR in polymer chemistry is reviewed in this paper. It is expected that this reaction will arouse the attention of polymer chemists and play a new role in polymer science.     

Study on backward-facing step flow and heat transfer characteristics of hybrid nanofluids

Journal of Thermal Analysis and Calorimetry - As high heat dissipation has increasingly become the primary factor restricting the capability of electronic elements, and the high temperature of the...