Synthesis of terminally substituted stilbene-tolane liquid crystals

Methods for synthesizing substituted alkyl and fluoro stilbene-tolane (PTPDP) liquid crystal materials are presented. These compounds show a slightly higher birefringence than the analogous bistolanes, but higher melting points and heats of fusion. Potential applications of these compounds for optical communications and displays are discussed.     

基于磷光材料的低给体比例有机太阳能电池

本文以低比例的磷光材料作为给体,制备了基于MoOx/C60:x%Ir(ppy)3的有机太阳能电池(OPV)器件.其中,C60为高比例的受体材料,金属配合物Ir(ppy)3为低比例的给体材料,MoOx为阳极缓冲层.通过一系列不同Ir(ppy)3比例的OPV器件对比研究,得出了最优器件结构.研究发现,当Ir(ppy)3比例足够小时,器件表现为肖特基势垒,开路电压(VOC)较大,短路电流(JSC)较小;随着Ir(ppy)3比例的增加,VOC逐渐减少,而JSC逐渐增大;当进一步增加Ir(ppy)3比例时,VOC趋于稳定,JSC开始减小.结果显示,5%Ir(ppy)3比例的器件性能最佳,效率达1.7%.为了使器件效率得到进一步提升,本研究组采用吸收光谱范围比C60更宽的C70作为受体材料,使光电转换效率进一步提升至3.0%.     

Reducing Detrimental Defects for High‐Performance Metal Halide Perovskite Solar Cells

In several photovoltaic (PV) technologies, the presence of electronic defects within the semiconductor band gap limit the efficiency, reproducibility, as well as lifetime. Metal halide perovskites (MHPs) have drawn great attention because of their excellent photovoltaic properties that can be achieved even without a very strict film‐growth control processing. Much has been done theoretically in describing the different point defects in MHPs. Herein, we discuss the experimental challenges in thoroughly characterizing the defects in MHPs such as, experimental assignment of the type of defects, defects densities, and the energy positions within the band gap induced by these defects. The second topic of this Review is passivation strategies. Based on a literature survey, the different types of defects that are important to consider and need to be minimized are examined. A complete fundamental understanding of defect nature in MHPs is needed to further improve their optoelectronic functionalities.     

A novel molecular imprinting polymer for the selective adsorption of D-arabinitol from spiked urine

In this research, molecular imprinting polymers (MIPs) for D-arabinitol were synthesized using a bulk polymerization method through a noncovalent approach. The MIPs were prepared by using D-arabinitol as a template, acrylamide as a functional monomer, ethylene glycol dimethacrylateas cross-linker, benzoyl peroxide as an initiator and dimethyl sulfoxideas a porogen. MIPS was synthesized in several formulas with a different molar ratio of template to functional monomers and cross-linker. Fourier-transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM) were used to characterize the MIPs produced. A batch rebinding assay was used to test the binding efficiency of each formula. Batch rebinding test results revealed that MIPsF3 with a molar ratio of the template: monomer and crosslinker ratio respectively (1: 4: 25) had the highest binding capacity at 1.56 mgg ^-1 . The results of isotherm adsorption showed that the MIPs produced followed the Freundlich equation with an R-value of 0.97. The MIPs produced was also selective toward its isomeric compounds (i.e. L-arabinitol, adonitol, xylitol, and glucose). The extraction efficiency of the MIPs against D-arabinitol was 88.98%.     

物理气相传输(PVT)法生长碳化硅的晶体形态热应力分析

利用有限元方法对物理气相传输(PVT)法生长碳化硅晶体过程中出现的3种典型生长形态进行了热应力分析.结果表明:在3种晶体生长形态中,热应力最大值都出现在晶体与石墨坩埚盖接触区域;平面型生长形态中温度场及相应的热应变场和等效应力场分布均比较均匀;凸面型和凹面型生长形态的温度场及相应的热应变场和等效应力场分布均变化较大,而且在凸面型的中间区域和凹面型的边缘区域也存在较大的应力值.因此,为提高晶体质量,提出在石墨坩埚盖上沉积或反应生成碳化硅过渡层来减小热应力的改良方法,同时调整碳化硅晶体生长系统,尽量保证碳化硅晶体的平面型生长形态.     

高温高压下冲击波淬火的锆基大块金属玻璃的相演化过程研究

 采用同步辐射能散X射线衍射技术,研究了高温高压下利用冲击波淬火技术制备的Zr₄₁Ti₁₄Cu_12.5Ni₁₀Be_22.5大块金属玻璃的相演化过程。研究结果发现：在实验压力范围内,在不同压力下试样具有相同的初始析出相Zr₂Be₁₇,但是随后的相演化过程是不同的,根据应用压力的不同,试样的相演化过程可以分为3个不同的区域;另外,试样的晶化温度随着压力的增大而升高,但是在6.0 GPa存在一个突然的下降,在此压力点试样具有不同于其它压力点的相演化过程。相演化过程的不同和晶化温度的突然下降,可能归因于在不同压力下试样具有不同的原子构型。     

希夫碱钛配合物/三异丁基铝催化MMA本体聚合

经希夫碱缩合反应,制得水杨醛亚胺配体(1),其Na盐分别与TiCl4和CpTi-Cl3反应合成了新型希夫碱钛配合物{3,5-di-Br-2-(O)C6H2CHN[2(O)C6H4]}TiCl2(2);{3,5-di-Br-2-(O)C6H2CHN[2(O)C6H4]}[TiCl(C5H5)](3).以GC-MS,1HNMR和元素分析对中间产物及配合物进行了表征.以Al(i-Bu)3为助催化剂,详细考察了聚合时间、温度、Al/Cat和MMA/Cat的摩尔比对催化MMA本体聚合的影响.两个催化体系的聚合转化率均可以达到62%左右.2/Al(i-Bu)3(A)催化体系在聚合条件MMA/Cat(摩尔比)=2 000,Al/Cat(摩尔比)=20,T=60℃,t=15 h下,Mη可以达到3.6×105,相对分子质量分布2.14;3/Al(i-Bu)3(B)催化体系在相同聚合条件下,Mη可以达到4.3×105,相对分子质量分布2.44.红外光谱分析表明,A,B两个催化体系所得的PMMA的间同含量分别为85%和86%左右.     

高压下碱卤晶体的三参量等温状态方程

 由等温体积弹性模量的定义及其与压强关系的假设出发,导出了一个新的适用于高压下碱卤晶体的三参量等温状态方程。计算了室温下NaCl晶体在0～30 GPa压强范围内、CsCl晶体在0～40 GPa压强范围内的相对体积以及NaCl晶体在0～30 GPa压强范围内的等温体积弹性模量,计算结果与实验值一致。对等温体积弹性模量及其对压强的一阶、二阶导数与压强的关系进行了讨论,指出压强趋于无穷大时的等温体积弹性模量是常数。     

4种等温物态方程适用性的比较研究

 通过分析现有文献,认为4种两参数的物态方程在高压物理研究中较为流行,它们是Vinet、Baonza、Morse和Born-Meyer（BM）方程。将这4种方程用于拟合50种材料的实验压缩数据,得出了零压下压缩模量及其一阶压力导数的优化取值,并计算了4种方程的平均压力误差。结果表明,Morse方程的精度最高,对50种材料的平均拟合误差为0.557 6%;BM方程次之,平均误差为0.615 1%;Vinet和Baonza方程的误差大一些,分别为0.788 9%和0.833 3%。对8种典型材料计算了压力误差随压强变化的曲线,所得结果与平均误差的趋势一致,也是Morse方程的精度最高。在宽广压力范围的高压物态方程研究中,推荐使用Morse方程。