2-苯基噻吩的电化学聚合

聚噻吩及其衍生物是一类重要的导电高分子材料,它们具有良好的导电性、高度稳定性以及易于调控的分子链结构．因此,自从人们发现聚噻吩以来,噻吩类化合物,尤其是3-取代噻吩的聚合和表征一直受到人们的广泛关注[1,2]．相对而言,关于2-取代噻吩的聚合几乎还是空白,以往人们对其进行电化学聚合的尝试是不成功的[3]．     

Alleviating hysteresis and improving device stability of perovskite solar cells via alternate voltage sweeps

The anomalous hysteresis in a perovskite solar cell induced by an asymmetric field is confirmed by a capacitance–voltage measurement. By applying several cycles of alternating reverse and forward scans, this hysteresis phenomenon is obviously alleviated, resulting in a hysteresis-less state in the perovskite solar cell. Meanwhile, the open-circuit voltage and power conversion efficiency of the perovskite solar cell are enhanced by 55.74% and 61.30%, respectively, while the current density and fill factor keep almost invariable. The operation of alleviating hysteresis is essential for further research and is likely to bring in performance gains.     

《新型二维纳米材料》专辑序言——新型二维纳米材料:掀起未来技术革命

Two-dimensional(2D) nanomaterials possess sheet-like structures with the thickness of nanoscale, but the lateral size is infinite. In 2004, Andre Geim and co-workers at the University of Manchester successfully exfoliated a sheet of graphene from graphite by the micromechanical cleavage technique, which marked the beginning of 2D nanomaterials. Given the ultrahigh carrier mobility, excellent mechanical property, good thermal stability, superior thermal conductivities and huge specific surface area of graphene, it causes general exploration of other graphene-like 2D nanomaterials.===The 2D feature is unique to access unprecedented physical, chemical, electronic and optical properties. For example, the electron confinement in two dimensions makes them ideal candidates for the fundamental study in condensed matter physics and electronic/optoelectronic devices; the large lateral size endows them with huge surface area and high exposure of active sites. Due to their unique properties, 2D nanomaterials have promising applications in energy storage and conversion, electronic devices, catalytic reaction, sensing and biomedicine. By now, nearly 20 types of 2D nanomaterials have been studied, such as graphene, graphitic carbon nitride(g-C₃N₄), transition metal dichalcogenides(TMDs), transition metal carbides/nitrides(MXenes), layered double hydroxides(LDHs), transition metal oxides(TMOs), Ⅲ to Ⅵ layered semiconductor(MX₄), and perovskite-type hybrids(AMX₃).===In this special issue of the novel 2D nanomaterials, we selected 12 related articles in reviews, research papers and brief communications involving supercapacitor, electrochemical catalysis, sensing, battery, fluorescence, water treatment and antiflaming performance of 2D nanomaterials. We hope that readers will have a deep understanding of the current development of 2D nanomaterials, and find it beneficial to their future researches.===Toward this end, I greatly appreciate the outstanding contribution of all authors, as well as the strenuous efforts from the editorial staff members.     

人工欧泊填充InP后的形貌和反射谱特性

制备了人工opal晶体模板,运用MOCVD方法在SiO2人工opal球体间填充了高折射率的InP晶体,选择了MOCVD生长InP的有关参数.样品扫描电子显微镜及反射谱结果检测显示,InP晶体在二氧化硅间隙中的生长是均匀的,具有较好的结晶质量;高介电常数的InP的填充使人工欧泊光子晶体的光子禁带效应增强,反射峰移向长波长区.光学特性检测结果与理论计算值得到较好的符合.     

Blue InGaN light-emitting diodes with dip-shaped quantum wells

InGaN based light-emitting diodes (LEDs) with dip-shaped quantum wells and conventional rectangular quantum wells are numerically investigated by using the APSYS simulation software. It is found that the structure with dip-shaped quantum wells shows improved light output power, lower current leakage and less efficiency droop. Based on numerical simulation and analysis, these improvements on the electrical and the optical characteristics are attributed mainly to the alleviation of the electrostatic field in dip-shaped InGaN/GaN multiple quantum wells (MQWs).     

双波长InGaN/GaN多量子阱发光二极管的光电特性

为了实现高显色指数和流明效率的白光发光二极管,在(0001)蓝宝石衬底上利用金属有机化学气相沉积系统,生长了双波长发射的InGaN/GaN多量子阱发光二极管结构.通过对不同In组分含量的双波长发射发光二极管结构的光致发光和电致发光性能进行分析,结果表明In组分含量对双波长发射发光二极管的光致发光谱的稳定性及发光效率有重...     

双波长InGaN/GaN多量子阱发光二极管的光电特性

为了实现高显色指数和流明效率的白光发光二极管,在（0001）蓝宝石衬底上利用金属有机化学气相沉积系统,生长了双波长发射的InGaN/GaN多量子阱发光二极管结构.通过对不同In组分含量的双波长发射发光二极管结构的光致发光和电致发光性能进行分析,结果表明In组分含量对双波长发射发光二极管的光致发光谱的稳定性及发光效率有重要影响.此外,用双蓝光发射的芯片来激发YAG:Ce荧光粉实现了高显色指数白光发射.     

Doping transition metal ions as a method for enhancement of ablation rate in femtosecond laser irradiation of silicate glass

We present a doping method to improve the femtosecond laser ablation rate and promote ablation selectivity. Doping transition metal ions, Co2＋ or Cu2＋, in silicate glass apparently change absorption spectroscopy and induce resonant absorption at wavelengths of 600 and 800 nm, respectively. Comparing with femtosecond laser processing of the same glass without doping, we find that the threshold fiuenee decreases and the ablation rate increases in resonant absorption in doped silicate glass. Resonant absorption effectively increases multiphoton ionization for seed-free electron generation, which in turn enhances avalanche ionization.     

Simulation study of blue InGaN multiple quantum well light-emitting diodes with different hole injection layers

InGaN-based light-emitting diodes with p-GaN and p-AlGaN hole injection layers are numerically studied using the APSYS simulation software.The simulation results indicate that light-emitting diodes with p-AlGaN hole injection layers show superior optical and electrical performance,such as an increase in light output power,a reduction in current leakage and alleviation of efficiency droop.These improvements can be attributed to the p-AlGaN serving as hole injection layers,which can alleviate the band bending induced by the polarization field,thereby improving both the hole injection efficiency and the electron blocking efficiency.     

Y对Fe-Si-B 合金非晶形成能力及软磁性能的影响

本文通过铜模吸铸法和单辊甩带法分别制备出一系列楔形试样和非晶条带试样, 系统研究了稀土金属Y对Fe₇₈Si₉B₁₃合金非晶形成能力及其软磁性能的影响. 结果表明, 少量Y取代 Fe-Si-B 非晶合金中的Fe 可大大提高该合金的非晶形成能力并促进过冷液相区的产生. 当Y含量为3 at.%时, 合金具有最大的非晶形成能力, 其临界厚度为313 μm, 相应的非晶过冷液相区宽度达到65 K. 该系列非晶合金具有优良的软磁性能, 其矫顽力(H_c)均低于200 A/m, Y含量为1 at.%时, 饱和磁感应强度(B_s) 达到最大值1.67 T.