All-solution-processed PIN architecture for ultra-sensitive and ultra-flexible organic thin film photodetectors

An ideal organic thin film photodetectors (OTFPs) should adopt a hierarchical, multilayer p-type/blend-type/n-type (PIN) structure, with each layer having a specific purpose which could greatly improve the exciton dissociation while guarantee efficient charge transport. However, for the traditional layer-by-layer solution fabrication procedure, the solvent used can induce organic material mixing and molecular disordering between each layer. Hence, such architecture for OTFPs can now only be formed via thermal evaporation. In this paper, a contact-film-transfer method is demonstrated to all-solution processing organic PIN OTFPs on flexible substrates. The fabricated PIN OTFPs exhibit high photoresponse and high stability under continuous mechanical bending. Hence, the method we described here should represent an important step in the development of OTFPs in the future.     

Analysis and deconvolution of dimethylnaphthalene isomers using gas chromatography vacuum ultraviolet spectroscopy and theoretical computations

An issue with most gas chromatographic detectors is their inability to deconvolve coeluting isomers. Dimethylnaphthalenes are a class of compounds that can be particularly difficult to speciate by gas chromatography – mass spectrometry analysis, because of their significant coelution and similar mass spectra. As an alternative, a vacuum ultraviolet spectroscopic detector paired with gas chromatography was used to study the systematic deconvolution of mixtures of coeluting isomers of dimethylnaphthalenes. Various ratio combinations of 75:25; 50:50; 25:75; 20:80; 10:90; 5:95; and 1:99 were prepared to test the accuracy, precision, and sensitivity of the detector for distinguishing overlapping isomers that had distinct, but very similar absorption spectra. It was found that, under reasonable injection conditions, all of the pairwise overlapping isomers tested could be deconvoluted up to nearly two orders of magnitude (up to 99:1) in relative abundance. These experimental deconvolution values were in agreement with theoretical covariance calculations performed for two of the dimethylnaphthalene isomers. Covariance calculations estimated high picogram detection limits for a minor isomer coeluting with low to mid-nanogram quantity of a more abundant isomer. Further characterization of the analytes was performed using density functional theory computations to compare theory with experimental measurements. Additionally, gas chromatography – vacuum ultraviolet spectroscopy was shown to be able to speciate dimethylnaphthalenes in jet and diesel fuel samples.     

Synthesis and biological evaluation of substituted indazolyl amide derivatives as S-adenosyl-L-homocysteine hydrolase inhibitors

A series of novel amide derivatives bearing an indazole moiety were synthesized and evaluated for their in vitro S-adenosyl-L-homocysteine hydrolase (SAHase) inhibitory activity. Among these compounds, 8b, 8m, 8r and 8w showed better or similar inhibitory effects compared to the positive control aristeromycin. These results provide a novel lead for the discovery of more potent non-adenosine analogs as SAHase inhibitors.     

Oscillatory shear‐induced alignment of ketjen black conductive particles in polylactic acid and its effect on the electrical anisotropy

This study aligned Ketjen black (KB) particles along one preferred direction in a polylactic acid (PLA) matrix using an oscillatory shear flow and investigated the effect of aligned KB on the electrical anisotropy. Under the oscillatory shear, the KB particles are aligned along the flow direction in the PLA matrix, resulting in an oriented conductive network. When the concentration of KB is in the range of 0.88–1.56 vol %, the electrical volume resistivity along the flow direction (ρ_∥) decreases to ～3 × 10⁴ Ω m and that perpendicular to the flow direction (ρ_⊥) remains at ～1 × 10¹⁰ Ω m, showing an extremely large electrical anisotropy, and the ρ_⊥/ρ_∥ value is 3–4 orders of magnitude higher than that of previously reported carbon‐nanotube‐based electrical anisotropic composites. This strong anisotropy is attributed to the preferential alignment of KB particles with lower percolation threshold for conductive path along the flow direction. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 369–373     

Adsorption of toluene and acetone vapors on microwave-prepared activated carbon from agricultural residues: isotherms,kinetics, and thermodynamics studies

Research on Chemical Intermediates - Activated carbons produced with agricultural residues have attracted substantial attention in recent years. However, much work remains to be done. The current...     

STUDIES ON THE SPHERULITE FORMATION IN MELT CAST POLYCAPROLACTONE BASED POLYURETHANES

A series of PCL/MDI/BDO segmented polyurethanes have been synthesized by two-step method in solution.The hard segment content ranges from 10% to 48% by weight, and the molecular weight of PCL diols is 1500. Hard segment spherulites have been observed in compression molded specimens of all of the samples except the one of the lowest hard segment content. The difficulty in sphernlite formation was explained as only in a small temperature range,the microphase separation rate may be faster than the crystallization rate and all these processes are very slow due to the hydrogen bonding between hard and soft segments and the interactions between hard segments themselves. PCL soft segments of molecular weight 1500 is still crystallizable and may form different crystalline superstructures.     

Calculations of Energy-Loss Function for 26 Materials

We present a fitting calculation of energy-loss function for 26 bulk materials, including 18 pure elements (Ag, Al, Au, C, Co, Cs, Cu, Er, Fe, Ge, Mg, Mo, Nb, Ni, Pd, Pt, Si, Te) and 8 compounds (AgCl, Al₂O₃, AlAs, CdS, SiO₂, ZnS, ZnSe, ZnTe) for application to surface electron spectroscopy analysis. The experimental energy-loss function, which is derived from measured optical data, is fitted into a finite sum of formula based on the Drude-Lindhard dielectric model. By checking the oscillator strength-sum and perfectscreening-sum rules, we have validated the high accuracy of the fitting results. Furthermore, based on the fitted parameters, the simulated reflection electron energy-loss spectroscopy (REELS) spectrum shows a good agreement with experiment. The calculated fitting parameters of energy loss function are stored in an open and online database at http://micro.ustc.edu.cn/ELF/ELF.html.