Laser spectroscopic investigation of a new precursor-type polyparaphenylenevinylene

Optical, structural and morphological properties of thin films of polyparaphenylenevinylene (PPV) formed by an alkyl sulfinyl precursor route have been studied. Thin films were fabricated on an optical glass and on quartz glass either by spin-coating of the precursor solution or by layer-by-layer deposition using Langmuir–Blodgett technique. PPV precursor films were also spin-coated on gold-coated glass in order to study thin-film optical parameters by surface plasmon spectroscopy. We have been successful in forming about 40 precursor mono layers on quartz glass by Langmuir–Blodgett technique using optimized surface pressure and dipping conditions. After thermal conversion of the precursor layers good quality fluorescent PPV films of yellow colour have been obtained. Optical characterization of the films was carried out by linear absorption and emission spectroscopy, ellipsometry, and surface plasmon spectroscopy. Structural and morphological studies on the thin films were carried out by using X-ray scattering and atomic force microscopy. Wave-guided travelling-wave laser action has been achieved in a PPV film on quartz glass. The sample was transversally pumped with picosecond laser pulses (wavelength 347.15 nm, duration 35 ps). Laser emission occurred at 550 nm for pump pulse energy densities above .     

利用钆配合物调节激基复合物发光颜色的一种有机发光二极管

报道一种可用钆配合物[Gd（DBM）3bath]调节电致发光（EL）颜色的有机发光二极管（OLED）。该有机发光二极管是在空穴传输层（m-MTDATA）和电子传输层（TPBI）之间插入-薄层Gd（DBM）3bath。随着Cd（DBM）3bath厚度增加,二极管的发光颜色呈现出绿色（主峰525nm）-黄色-橙色（主峰593rim）变化。该二极管的电致发光主要来自界面激基复合物的发射而不是来自各有机功能层;而发光颜色的变化是由于两种激基复合物发射的相对强度的改变。     

Mild synthesis of a Zn(II) metal organic polymer and its hybrid with activated carbon: Application as antibacterial agent and in water treatment by using sonochemistry: Optimization,kinetic and isotherm study

In this work, a room temperature and short method (30 min) for synthesis of nanosized rod-like metal organic polymer (MOP) has been described. Reaction of 1,4-phenylenedioxy diacetic acid with zinc salt leads to the formation of [Zn(C₁₀H₈O₆)(H₂O)₄]_n and subsequently was loaded on activated carbon following sonication and structurally characterized by FTIR, SEM, EDX and XRD analysis. The combination of this new composite with sonication was applied for rapid and efficient adsorption of Bromocresol Purple (BCP). Effects of initial BCP concentration, mass of adsorbent and sonication time on response were investigated and optimized by central composite design (CCD). Analysis of variation (ANOVA) was adapted to experimental data to find best optimum conditions which was set at 15.22 mg L⁻¹, 2.41 min, 0.02 g and 0.009 mg for initial BCP concentration, sonication time and adsorbent mass, respectively. Conduction of similar experiments at specified condition permit achievement of 98.69% removal percentage. 1,4-phenylenedioxy diacetic acid and Zn(NO3)₂.4H₂O which have applied for preparation of MOP are interesting antibacterial properties and accordingly MOP was screened in vitro for their antibacterial actively against Proteus vulgaris bacteria and experimental results reveal this MOP was able to inhibit growth of the tested bacteria. The experimental data were best fitted by pseudo-second order and Langmuir for kinetic model and the adsorption equilibrium isotherm, respectively.     

PARAFAC法解析太湖水体DOM三维荧光光谱

采用平行因子法(PARAFAC法)对太湖水样溶解性有机质(DOM)三维荧光光谱进行解析。通过比较因子数分别为3,4和5时,PARAFAC模型的核一致函数、 激发和发射光谱误差平方和、 各水样模拟的三维荧光光谱和残差谱图等情况,选择因子数为3作为太湖水样DOM三维荧光光谱PARAFAC模型的最佳因子数。太湖水样DOM的3类主要荧光组分分别是类腐殖质荧光物质、 类色氨酸荧光物质、 类酪氨酸荧光物质。     

PTCDA/P-Si光电探测器欧姆接触层的XPS测试分析

在光电探测器PTCDA/P-Si芯片的有机层表面,成功制作出了比接触电阻为4.5×10-5Ω·cm2的低阻欧姆接触层。利用X射线光电子能谱(XPS)对Al/Ni/ITO的欧姆接触层界面的电子状态进行了测试和分析。结果表明,ITO中的In3d及Sn3d各出现两个分裂能级的谱峰,它们是In和Sn原子处于氧化环境的结合能。Ni2p有两个谱峰Ni2p(1)及Ni2p(2),低结合能位置Ni2p(1)对应于Ni原子被X射线激发产生的谱峰,说明NiITO之间没有发生化学反应,Ni层阻止了Al层被氧化成Al2O3;高结合能Ni2p(2)谱峰说明已形成了Al3Ni冶金相,有利于低阻欧姆接触层的形成。     

The pKa theoretical estimation of C―H,N―H,O―H and S―H acids in dimethylsulfoxide solution

A scheme for the pK_a estimation of organic acids in dimethylsulfoxide (DMSO) solution based on quantum chemical calculations is proposed. The procedure of pK_a calculation requires several steps. The first is the calculation of the gas phase acidity of the compound. The G3MP2B3, G4MP2 as well as CBS‐QB3 composite methods made it possible to estimate values of gas phase acidities of an extensive set of structures with a high confidence level (standard deviations equal to 1.15, 1.13 and 1.29 kcal mol^?1, respectively; the test set included 91 compounds). The second step is the computation of the solvation correction with the integral equation formalism version of polarizable continuum model (IEF‐PCM)–B3LYP/6‐311+G(d,p) approximation. Within the bounds of our approach, the medium properties were covered only by the PCM model, i.e. the proposed procedure neglects specific interactions between DMSO and the solute. It was determined that the approach to pK_a estimation mentioned above is the most balanced in terms of accuracy, resource intensity and computation time cost. In the third step, the error of the pK_a calculation was decreased by correlation allowances. Correlation allowances were determined for each acid class (62 С―Н, 55 N―Н, 24 O―Н and 5 S―Н acids) in the range of 50 units in terms of logarithmic scale using the test set including 146 compounds. Seven O―H acids showing the ability to form cyclic dimers were separated into a discrete group. The proposed methodology was applied to the estimation of pK_a for trans‐ and cis‐dimethyl‐4,5‐dihydro‐3H‐pyrazol‐3,5‐dicarboxylates as well as for 5‐fluorouracil subject to competitive dissociation, the latter by N1―H or N3―H bonds. Copyright © 2014 John Wiley & Sons, Ltd.     

Short electrospun composite nanofibers: Effects of nanoparticle concentration and surface charge on fiber length

Short composite nanofibers were fabricated by electrospinning polymer/TiO₂ nanoparticle solutions of 13 wt. % cellulose acetate as a polymer under a voltage of 5.5 kV and at a flow rate of 0.1 μL/min, and the nanoparticles could be added in concentrations as high as 50 wt. %. The length of the short composite nanofibers was significantly decreased from 112 to 70 μm by the addition of at least a 5 wt. % concentration of nanoparticles, and it gradually continued to decrease as the nanoparticle concentration was increased. The length of the short composite nanofibers with a low concentration of nanoparticles was affected by the surface charge of the nanoparticles, and negatively charged nanoparticles readily dispersed to the negatively charged polymers in solution, which resulted in an elongation of the fabricated short composite nanofibers.     

偶氮基染料掺杂薄膜的双光子图象存储

研究了偶氮基染料掺杂薄膜ＭＯ－ＰＶＡ和ＥＯ－ＰＶＡ的双光子存储特性。在对薄膜用Ａｒ＾＋激光作预激发下实现了Ｈｅ－Ｎｅ激光的红光存储。获得了实时和短时存储照片。光电记录存储曲线，分析了双光四能级系统的存储机制。实现确定了最佳预激发功率约为０．２８Ｗ／ｃｍ＾２，最小Ｈｅ－Ｎｅ光可存储功率密度低于０．２Ｗ／ｃｍ＾２。     

激光诱导水体频率上转换的荧光发射

用Nd：YAG的二倍频532 nm激光对几种不同水体的激光诱导荧光(LIF)光谱进行了测量,利用特征光谱荧光标记(SFS)技术指认出水体中溶解有机物(DOM)、叶绿素a(Chl a)及类胡萝卜素等物质的特征光谱带。指出在455 nm波长处具有较大强度的荧光峰是附属色素中抗氧化作用的类胡萝卜素(PPC)的贡献。提出了激光诱导PPC荧光频率上转换发射的动力学模型。     

钾掺杂对三联苯的超导特性探寻

新型超导材料的设计合成及其超导机理的探索是目前凝聚态物理学领域的重要研究方向. 本文采用高真空热烧结方法制备了钾掺杂对三联苯粉末材料并表征了它们的晶体结构、分子振动、磁学及超导特性. X射线衍射图谱和拉曼光谱表明在烧结样品中除存在钾掺杂对三联苯和KH外, 还含有苯环重组的C₆₀和石墨成分. 拉曼光谱中部分峰位的红移进一步证实钾成功掺入对三联苯分子晶体中并将4 s电子转移到C原子上. 零场冷却磁性测量结果表明: 多数样品在整个温度测量区间表现为居里顺磁性, 但少数样品呈现出抗磁性, 而且在17.86, 10.00 和6.42 K三个温度点出现磁化率突降的反常行为, 其中17.86 K处的突降很可能源于钾掺杂C₆₀引起的超导转变, 而后两者可能与钾掺杂对三联苯导致的超导相关. 研究结果有助于理解金属掺杂芳香烃有机超导体这一新兴超导家族的晶体生长和物理特性, 同时也提供了一种低温制备C₆₀和石墨的新方法.