High performance organic planar heterojunction solar cells by controlling the molecular orientation

A highly efficient planar heterojunction OSC based on zinc phthalocyanine (ZnPc)/fullerene (C₆₀) by controlling the orientation of the ZnPc by using copper iodide (CuI) as the interfacial layer is reported. The proportion of face-on ZnPc molecules was increased significantly on the CuI layer compared to the layer without the CuI layer, which was analyzed with wide-angle X-ray scattering (WAXS) and optical absorption. The power conversion efficiency (PCE) of the orientation controlled planar heterojunction OSC was remarkably enhanced to 3.2 ± 0.1% compared with 1.2 ± 0.1% of the conventional OSCs without the control of the molecular orientation. By inserting the 3-nm-thick CuI layer, J_SC, V_OC and FF have increased from 4.6 ± 0.2 to 8.9 ± 0.2 mA cm^?2, from 0.48 ± 0.01 to 0.59 ± 0.02 V, and from 0.56 ± 0.01 to 0.61 ± 0.02, respectively. V_OC enhancement is discussed with the result of the ultraviolet photoemission spectra (UPS) measurements.     

On a method for solving a convolution-type equation with the use of difference equations

The solution of a convolution-type equation for two unknown compactly supported functions for the case in which the kernel of the integral operator has Fourier transform in the form of the ratio of two polynomials of exponentials and the right-hand side satisfies additional conditions like the evenness-oddness, absence of zeros, etc. is reduced to the solution of a system of difference equations. We suggest a solution method for that system.     

Primary, secondary, and tertiary amines for CO2 capture: designing for mesoporous CO2 adsorbents

CO(2) emissions, from fossil-fuel-burning power plants, the breathing, etc., influence the global worming on large scale and the man's work efficiency on small scale. The reversible capture of CO(2) is a prominent feature of CO(2) organic-inorganic hybrid adsorbent to sequester CO(2). Herein, (3-aminopropyl) trimethoxysilane (APTMS), [3-(methylamino)propyl] trimethoxysilane (MAPTMS), and [3-(diethylamino) propyl] trimethoxysilane (DEAPTMS) are immobilized on highly ordered mesoporous silicas (SBA-15) to catch CO(2) as primary, secondary, and tertiary aminosilica adsorbents. X-ray photoelectron spectroscopy was used to analyze the immobilized APTMS, MAPTMS, and DEAPTMS on the SBA-15. We report an interesting discovery that the CO(2) adsorption and desorption on the adsorbent depend on the amine type of the aminosilica adsorbent. The adsorbed CO(2) was easily desorbed from the adsorbent with the low energy consumption in the order of tertiary, secondary, and primary amino-adsorbents while the adsorption amount and the bonding-affinity increased in the reverse order. The effectiveness of amino-functionalized (1(o), 2(o), and 3(o) amines) SBA-15s as a CO(2) capturing agent was investigated in terms of adsorption capacity, adsorption-desorption kinetics, and thermodynamics. This work demonstrates apt amine types to catch CO(2) and regenerate the adsorbent, which may open new avenues to designing "CO(2) basket".     

Effect of temperature and a weakly polar organic medium on water localization in slit-like pores of various sizes in microporous activated carbon

The joint adsorption of water and methane in pores of the synthetic carbon adsorbent with specific surface area of 3463 m²/g was studied by ¹H NMR spectroscopy. It was shown that during adsorption of water and methane in pores of activated carbon AC86 under conditions of low surface filling the adsorbate molecules are localized not only in micropores, but in mesopores as well, and are revealed in the spectra as several signals with different values of the chemical shift. A substantial drop in the magnetic shielding effect of the carbon surface was detected upon a reduction in temperature; this is explained by the presence of two energy minima on the curves of the adsorption potential energy (close to the walls and in the center of pores) and allows the migration of adsorbed molecules from the walls to the center of pores, which are characterized by a lower shielding effect.     

Characterization of surface properties and cytocompatibility of ion-etched chitosan films

Surface modification of biomaterials has been highlighted by biomedical engineers as a facile method for improving cell-biomaterial interactions without the expense and time required to develop new materials. In the present study, we investigated the influence of ion-etching on the surface characteristics of chitosan films using XPS and ATR FT-IR. The physiological behavior of human dermal fibroblasts (hDFs) grown on such surfaces was studied by evaluating adhesive and proliferative properties, and by examining surface morphologies of hDFs using AFM. hDFs displayed different shapes depending on the ion-etching time. hDFs grown on chitosan films ion-etched for 5 min displayed better development of lamellipodia and filopodia around the hDF periphery than did cells grown on nonmodified chitosan film, whereas hDFs did not spread well on films ion-etched for 20 min. Films ion-etched for 5 min or less had higher NH(2) and COOH contents, leading to enhanced hDF adhesion and proliferation.     

Chemical Control of Yeast Cell Division by Cross‐Linked Shells of Catechol‐Grafted Polyelectrolyte Multilayers

The chemical control of cell division has attracted much attention in the areas of single cell‐based biology and high‐throughput screening platforms. A mussel‐inspired cytocompatible encapsulation method for achieving a “cell‐division control” with cross‐linked layer‐by‐layer (LbL) shells is developed. Catechol‐grafted polyethyleneimine and hyaluronic acid are chosen as polyelectrolytes for the LbL process, and the cross‐linking of polyelectrolytes is performed at pH 8.5. Cell division is controlled by the number of the LbL nanolayers and cross‐linking reaction. We also suggest a new measuring unit, , for quantifying “cell‐division timing” based on microbial growth kinetics.

     

Spin wave measurements over the full Brillouin zone of multiferroic BiFeO3

Using the inelastic neutron scattering technique, we measured the spin wave dispersion over the entire Brillouin zone of room temperature multiferroic BiFeO(3) single crystals with magnetic excitations extending to as high as 72.5 meV. The full spin waves can be explained by a simple Heisenberg Hamiltonian with a nearest-neighbor exchange interaction (J=4.38 meV), a next-nearest-neighbor exchange interaction (J'=0.15 meV), and a Dzyaloshinskii-Moriya-like term (D=0.107 meV). This simple Hamiltonian determined, for the first time, for BiFeO(3) provides a fundamental ingredient for understanding the novel magnetic properties of BiFeO(3).     

极低频电磁场曝露对于大鼠敏感组织红外光谱特征的影响

极低频电磁场非热生物效应的发生与生物组织接受电磁辐射后微观结构的改变有关,利用红外光谱学分析方法可以有效的研究电磁辐射生物效应发生的微观机制。研究了极低频电磁场曝露对于大鼠电磁敏感组织红外光谱特征的影响,对曝露于50 Hz,0.75 mT极低频电磁场作用20天的大鼠的血液、脑和睾丸组织的红外光谱与正常大鼠组织的红外光谱进行比较分析,从分子水平阐述了极低频电磁场曝露作用生物效应的发生机制。实验结果表明极低频电磁场曝露可导致大鼠敏感组织某些特征吸收峰峰位和峰强产生了规律性的变化,说明傅里叶变换红外光谱方法是研究电磁场不同生物效应的发生机制的一种有效手段。