Erbium-doped LAS glass ceramics prepared by spark plasma sintering (SPS)

Dense nanocrystalline glass ceramics of the Li₂O–Al₂O₃–SiO₂ (LAS) system were obtained by spark plasma sintering (SPS) of powders prepared by sol–gel method. The low thermal expansion LAS glass ceramic was chosen as host matrix for erbium ions. ZrO₂ was added both as a nucleating agent and as a possible good environment for the rare earth. The developed crystalline phases were analysed by X-ray diffraction (XRD) and the amorphous phase was quantified. Scanning and transmission electron microscopy (SEM, TEM) was used to investigate the microstructure. A different behaviour during the crystallisation process was observed between the sample prepared through the sintering of powders and the glass produced by the melting technique. A photoluminescence characterisation was also performed.     

High-performance OLEDs based on 4,5-diaza-9,9′-spirobifluorene ligated rhenium(I) complex with enhanced steric hindrance

Highly efficient and emitter concentration insensitive phosphorescent electroluminescent devices based on a novel rhenium(I) [Re(I)] complex, i.e., (4,5-diaza-9,9′-spirobifluorene)Re(CO)₃Br (Re-DSBF), were established. Non-doped device based on Re-DSBF as emitter exhibited outstanding performances with the peak luminance of 8531 cd m⁻² and maximum current efficiency of 16.8 cd A⁻¹, which were the highest reported to date for non-doped phosphorescent electroluminescent devices based on Re(I) emitters. Such excellent performances are closely related to the steric hindrance, large Stokes shift, and short luminescent lifetime of Re-DSBF complex. The luminescent mechanisms of those devices were also investigated.     

Configuration effect of novel bipolar triazole/carbazole-based host materials on the performance of phosphorescent OLED devices

A series of structurally isomeric carbazole/triazole (TAZ)-based bipolar host materials 1–4 were designed and synthesized. These new materials were found to exhibit wide energy gaps (E_g: 3.29–3.52 eV), high triplet energies (E_T: 2.56–2.76 eV), high thermal stability (T_d: 426–454 °C), high glass-transition temperatures (T_g: 116–156 °C) and excellent film-forming property. Green and blue emitting devices with fac-tris(2-phenylpyridine)iridium (Ir(ppy)₃) and iridium(III) bis(4,6-(di-fluorophenyl)pyridinato-N,C^2′)picolinate (FIrpic) as phosphorescent dopants have been fabricated. The measurements of turn-on voltages, efficiencies and luminance suggested that the practice of combining carbazole’s high triplet energy and excellent hole-transporting ability with TAZ’s electron-transporting ability at the molecular level was effectively translated into better performance at the device level. The molecular structure of compound 4 is well-correlated with its efficiencies, which (32.7 and 21.1 cd/A for green and blue devices, respectively) were the best among the four materials.     

Ti元素改性SiC_p/2024铝基复合材料的制备及其力学性能表征

采用搅拌铸造技术制备Ti元素改性SiC p/2024铝基复合材料,并对铸态材料进行二次加工,研究Ti改性、热挤压以及颗粒含量对复合材料力学性能的影响,通过X射线衍射(XRD)和扫描电子显微镜(SEM)等测试分析手段对物相结构进行表征。结果表明,增加Ti元素含量可以提高2024基体及其复合材料力学性能;热挤压有利于改善SiC颗粒与基体的界面结合,使材料性能较铸态显著提高,并且在细化材料组织的同时还能使Ti元素的作用得到进一步加强;复合材料的综合力学性能在颗粒含量3%时达到最佳,其中热挤态拉伸强度和硬度分别可达311 MPa和HB133,较铸态2024基体分别提高了94.4%和84.7%。     

Electrocatalytic MOF-Carbon Bridged Network Accelerates Li+-Solvents Desolvation for High Li+ Diffusion toward Rapid Sulfur Redox Kinetics

Lithium-sulfur batteries are famous for high energy density but prevented by shuttling effect and sluggish electrochemical conversion kinetics due to the high energy barriers of Li⁺ transport across the electrode/electrolyte interface. Herein, the Li⁺-solvents dissociation kinetics is catalyzed and stimulated by designing a carbon bridged metal-organic framework (MOF@CC), aimed at realizing increased bare Li⁺ transport for the rapid conversion kinetics of sulfur species. Theoretical simulations and spectroscopic results demonstrate that the bridged MOF@CC well grants a special transport channel for accelerating Li⁺ benefited from aggregated anion/cation clusters. Moreover, the C N bridge between -NH₂ ligand in MOF and carbon shell enhances electron exchange, and thus promotes polysulfide catalytic efficiency and hinder polysulfide aggregation and accumulation. With the MOF@CC-modified separators, the assembled Li/S batteries deliver a reversible capability of 1063 mAh g^-1 at 0.5 C, a capacity retention of 88% after 100 cycles, and a high-rate performance of 765 mAh g⁻¹ at 5 C. Moreover, the large areal pouch cell with 100 µm Li foil and lean electrolyte is capable of stabilizing 855 mAh g⁻¹ after 70 cycles. These results well demonstrate the efficiency of catalyzing desolvation for fast Li+ transport kinetics and the conversion of polysulfides.     

Biomimetic Natural Biopolymer-Based Wet-Tissue Adhesive for Tough Adhesion,Seamless Sealed,Emergency/Nonpressing Hemostasis,and Promoted Wound Healing

Bioadhesives have been used in clinics among the most prospective alternatives to sutures and staples for wound sealing and repairing; however, they generally have inadequate adhesion to wet surfaces, improper mechanical strength, poor hemostasis, and cytotoxicity. To address these challenges, a robust wet tissue adhesive based on collagen and starch materials (CoSt) is designed in this study. CoSt hydrogels integrate the feature of drainage, molecular penetration and strengthen cross-linking similar to mussel, ivy, and oyster glues, which remove interfacial water quickly, reinforce tough dissipation and involve multiple reversible dynamic interactions. Therefore, they form strong adhesion and sutureless sealing of injured tissues, accompanying actuate robust biointerfaces in direct contact with tissue liquids or blood, resolving the crucial impediments with sutures and commercially accessible adhesives. The novel bioadhesive shows repeatable strong wet tissue adhesiveness (62 ± 4.8 KPa), high sealing performance (153.2 ± 35.1 mmHg), fast self-healing ability, excellent injectability, and shape adaptability. For different hemostatic needs in rat models of tail amputation, skin incision, severe liver, abdominal aorta, and transected nerve injuries, the CoSt hydrogel shows better hemostatic efficiency than fibrin glue because of the coordinate efficacy of tough wound sealing property, outstanding red blood cell arresting capability, and the activation of hemostatic barrier membrane. Moreover, in vivo investigation of the skin injury repair of the rat model validate that CoSt hydrogels accelerate wound healing and functional recovery via skin damage/defects. Tough wet adhesion, quick hemostasis, distinguished biocompatibility, suitability to match irregular-shaped target sites, and good wound healing promotion of the CoSt hydrogel makes it a prospective bioadhesive for various biomedical applications.     

半导体碳纳米管的长度分选及其薄膜晶体管性能研究

半导体型碳纳米管薄膜的高质量制备及其优化对于碳纳米管基电子器件具有重要意义.其中半导体型碳纳米管的长度是影响薄膜质量的重要因素之一.文章通过聚[9-(1-辛酰基)-9H-咔唑-2,7-二基](PCz)成功制备了高纯度半导体型碳纳米管溶液,经过循环沉积工艺,高效地降低了分散液中的短碳管含量,有效地提升了半导体型碳纳米管的平均长度,在此基础上通过标准工艺成功制备了高性能碳纳米管薄膜晶体管.结果显示,优化后的长碳纳米管溶液制备的薄膜晶体管具有优异的电学性能,其开关比高达107,迁移率高达34 cm2·V-1·s-1,比相应的短管性能提升了 3倍.     

Synthesis of 2-D nanostructured BiVO4:Ag hybrid as an efficient electrode material for supercapacitors

2-D BiVO₄ nanosheets with monoclinic phase were synthesized at room temperature, and incorporated with Ag to form BiVO₄:Ag hybrid materials. The experiments demonstrated that doping Ag has largely increased the electrochemical performances of supercapacitor. Furthermore, the specific capacitance can reach up to 109 F g^–1 at 1 A g^–1 (the undoped one is of 27 F g^–1); energy density has enhanced to 15.2 Wh kg^–1 compared with the pristine one without Ag (3.8 Wh kg^–1). Therefore, doping Ag into bismuth-based compound provides us an alternative approach for the synthesis of 2-D nanostructured hybrid as an efficient electrode material for supercapacitors     

硅基中长波红外减反微结构研究

采用微加工工艺在Si衬底上制备了微柱和微锥阵列,结合光学建模分析,研究了结构参数对中长波（2.5~9 m）红外光反射率的影响规律。使用严格耦合波分析方法（RCWA）计算的微结构反射光衍射效率与傅里叶红外变换光谱仪（FTIR）测试的反射率结果吻合较好。研究结果表明,Si基微结构对TM及TE偏振光均有良好的红外光减反特性,微锥结构具有更好的减反效果,2.5~6.5 m中红外偏振光的反射率低至2%,同时表现出良好的宽谱与广角度减反特性。