Morphological study of an intrinsically stretchable photovoltaic bulk heterojunction

Thin‐film polymer solar cell consisting of [6,6]‐phenyl‐C71‐butyric acid methyl ester (PC₇₁BM) and poly[[4,8‐bis[(2‐ethylhexyl)oxy]benzo[1,2‐b:4,5‐b′]dithiophene‐2,6‐diyl][3‐fluoro‐2‐[(2‐ethylhexyl)carbonyl]thieno[3,4‐b]thiophenediyl]] (PTB7) demonstrates elastic stretchability with the aid of a high boiling point additive, 1,8‐diiodooctane (DIO). The usage of DIO not only helps to form uniformly distributed nanocrystalline grains, but may also create free volumes between the nano‐grains that allow for relative sliding between the nano‐grains. The relative sliding can accommodate large external deformation. Large dichroic ratios of the optical absorption of both PC₇₁BM and PTB7 were observed under large‐strain deformation, indicating reorientation of the nanocrystalline PC₇₁BM and PTB7 polymer chains along stretching direction. The dichroic ratio decreases to nearly 1.0 as the blend was relaxed to 0% strain. Therefore, the nanometer‐size grain blending morphology provides an approach to impart stretchability to organic semiconductors that are otherwise un‐stretchable. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018 , 56, 814–820     

Chitosan/Ce(IV) redox polymerization‐based amplification for detection of DNA point mutation

Polymerization‐based signal amplification, a technique developed for use in rapid diagnostic tests, hinges on the ability to localize initiators as a function of interfacial binding events. We report here a new DNA detection method in which polymer growth in redox‐polymerization is used as a means to amplify detection signals. The introduction of biotin‐labeled chitosan (biotin‐CS) with highly dense amino groups into the polymerization amplification as macromolecular reducing agent, beneficially simplifies amplification operation, as well as, provides a large amount of initiation points to improve the sensitivity of detection. DNA hybridization, SA and biotin binding reactions led to the attachment of CS on a solid surface where specific DNA sequences were located. With the addition of the mixture containing monomer AM, crosslinker PEGDA and oxidant CAN onto the CS location, the growth of polymer films was triggered to render the corresponding spots readily distinguishable to the naked eye. Direct visualization of 0.21 fmol target DNA molecules of interest was demonstrated. Non‐small cell lung cancer p53 sequence was further selected as a proof‐of‐principle to detect DNA point mutation. The proposed method exhibited an efficient amplification performance for molecule detection, and paved a new way for visual diagnosis of biomolecules. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 1929–1937     

Charge-transfer complex coupled between polymer and H-aggregate molecular crystals

Crystal needles of N,N′-bis(1-ethylpropyl)-3,4,9,10-perylenebis(dicarboximide) (EPPTC) are produced through p-stacking and are embedded in the thin film of poly(9,9-din-hexylfluorenyl-2,7-diyl) (PFO) when the blend solution of EPPTC and PFO in p-xylene is spin-coated onto a glass substrate. Charge transfer (CT) complex is resolved from the spectroscopic response of the blend film, which is generated only when the PFO molecules are excited. Thus, the PFO molecules are specified as donors and the H-aggregated EPPTC as acceptors in the formation of CT state (CTS). The emission resulting from the CTS in the red is further recognized by its much longer lifetime than both the intrinsic emission of the individual EPPTC molecules and that of their pure aggregates. Near-field analysis verifies that the CTS form on the boundary between the PFO and the crystal phases. The CT exciton forms by bounding the hole left on HOMO of the donor (PFO) and the indirectly transferred electron to the H-aggregate state of EPPTC, which transits back to the ground state by emitting a photon at about 650 nm. This introduces special physics in the heterojunctions that are coupled with the H-aggregates and mechanisms important for the design of organic photovoltaic devices. © 2013 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2013     

Quantitation of memantine hydrochloride bulk drug and its tablet formulation using proton nuclear magnetic resonance spectrometry

The use of quantitative nuclear magnetic resonance spectrometry for the determination of non‐UV active memantine hydrochloride with relative simplicity and precision has been demonstrated in this study. The method was developed on a 500 MHz NMR instrument and was applied to determination of the drug in a tablet formulation. The analysis was performed by taking caffeine as an internal standard and D₂O as the NMR solvent. The signal of methyl protons of memantine hydrochloride appeared at 0.75 ppm (singlet) relative to the signal of caffeine (internal standard) at 3.13 ppm (singlet). The method was found to be linear (r² = 0.9989) in the drug concentration range of 0.025 to 0.80 mg/ml. The maximum relative standard deviation for accuracy and precision was <2. The limits of detection and quantification were 0.04 and 0.11 mg/ml, respectively. The robustness of the method was revealed by changing nine different parameters. The deviation for each parameter was also within the acceptable limits. The study highlighted possibility of direct determination of memantine hydrochloride in pure form and in its marketed tablet formulation by the use of quantitative NMR, without the need of derivatization, as is the requirement in HPLC studies. Copyright © 2016 John Wiley & Sons, Ltd.     

基于单片机的散体流量计的设计与开发

散状固体在加工、运输和配料时,常需要自动化的动态计量,和气、液或多相流比较,散体的种类繁多、物理特性差别较大,进行实时精确计量十分困难。目前对散体的动态计量所采用的冲板流量计、核子秤和电子皮带秤等方式,存在稳定性差、准确度低等问题。论文利用科里奥利原理和机械设计理论,从计量装置的硬件设计开始,到信号接收与显示、应用程序开发,最后进行系统的测试与标定,完成了一种基于单片机的散体流量计的整体设计。此流量计结构简单、检修工作量小,动态测量精度高、过载能力强,在进一步控制电机转速的情况下,还能调整其测量量程,可以适用于工业生产中不同的计量需要。     

向列相液晶弹性各向异性诱导液晶盒产生漏光的研究

为了阐述具有体缺陷结构的向列相液晶盒在暗态出现漏光的原因,以及边界锚定条件对漏光的影响,首先,建立了3个向列相液晶盒模型,它们具有不同的初始指向矢排布。接着,基于Landau-de Gennes理论,通过对指向矢场的缺陷动力学计算,得到液晶盒截面内平衡态的指向矢分布。最后,使用琼斯矩阵法将该截面内的指向矢分布以透过率的形式表示出来。模拟结果显示,在无外场条件下,当向列相液晶的弹性常数满足L2/L1≥1(K22/K11≤2/3)时,具有体缺陷结构的液晶盒展现出了自发的扭曲结构,导致了漏光的出现。且漏光强度随着缺陷结构和边界条件的不同而不同。本文模型很好地解释了体缺陷造成液晶盒在暗态出现漏光的原因,且模拟结果与工业生产过程中观察到的现象是一致的。     

电极对薄膜体声波谐振器性能的影响

采用有限元分析软件COMSOL Multiphysics仿真了三维结构的谐振器,探讨了不同的顶电极形状对谐振器性能的影响。有效机电耦合系数(k2teff)随电极-压电层厚度比增大而减小,其中电极形状为三角形的谐振器在厚度比为0.05时获得最大k2teff(5.73%)。品质因数Q值变化趋势与k2teff相反,由三角形电极在厚度比为0.25时,获得最大Q值为1 314。不同电极形状的谐振器的优值随电极-压电厚度比先增大后减小,最大值为65.4,由正方形电极在比值为0.15时获得。     

Determination of Solvent Systems for Blade Coating Thin Film Photovoltaics

With lab‐scale solution‐processed thin film photovoltaic (TFPV) devices attaining market relevant efficiencies, the demand for environmentally friendly and scalable deposition techniques is increasing. Replacing toxic halogenated solvents is a priority for the industrialization of solution‐processed TFPV. In this work, a generalized five‐step process is presented for fabricating high‐performance devices from nonhalogenated inks. Resulting from this process, several new solvent systems are introduced based on thiophene, tetralin, 1,2,4‐trimethylbenzene, o‐xylene, and anisole for blade coating of three different diketopyrrolopyrrole‐based (pDPP5T‐2, pPDPP5T‐2S, and P390) bulk heterojunctions applied in organic photovoltaic devices. Devices based on pDPP5T‐2S and P390 attain 5.6% and 6.1% efficiency, respectively, greater than the efficiency either material reached when processed from the halogenated solvent system commonly used. These processes are implemented without post‐deposition annealing treatments or additives. The Hansen solubility parameters of the pDPP5T‐2 material are obtained, and are used, along with wettability data on a variety of substrates, to determine optimum solvent combinations and ratios for deposition. This generalized five‐step process results in new nonhalogenated solvent pathways for the scalable deposition of thin film photovoltaic materials.     

Synthesis of calix[4]arene-based dipodal receptors: Competitive solvent extraction and liquid bulk membrane transport for selective recovery of Cu2+

A series of new p-tert-butylcalix[4]arene-based dipodal receptors are synthesised in high yields. The calix[4]arene units of all the receptors have been found to be present in cone conformation. To optimise the good extraction ability and high transport rate, we synthesised the receptors that differ from each other in their end groups. These receptors extract Cu²⁺  ion selectively from the buffered aqueous medium containing a mixture of metal ions. The receptor bearing four sp³ nitrogens has by far the greater ability to extract Cu²⁺  than the other receptors. All these receptors were effectively used for Cu²⁺  ion transport from the aqueous buffered source phase to the aqueous receiving phase.

     

Solution-processed bilayer photovoltaic devices with nematic liquid crystals

The cross-linking of polymerisable liquid crystalline semiconductors is a promising approach to solution-processable, multilayer, organic photovoltaics. Here we demonstrate an organic bilayer photovoltaic with an insoluble electron-donating layer formed by cross-linking a nematic reactive mesogen. We investigate a range of perylene diimide (PDI) materials, some of which are liquid crystalline, as the overlying electron acceptor layer. We find that carrier mobility of the acceptor materials is enhanced by liquid crystallinity and that mobility limits the performance of photovoltaic devices.