Organic solar cell research has attracted scientific and commercial interest in the last decade due to a rapid increase in power conversion efficiencies (PCEs). Today, PCEs in the range of 8–10 % have been obtained using conjugated polymers as electron-donor materials in combination with fullerene/other acceptors. However, to enable commercial applications, the efficiencies and lifetimes of organic solar cells still need to be improved significantly. In recent years, due to the potential advantages of Se-containing conjugated materials, namely, lower band gaps, rigidity, and strong Se⋅⋅⋅Se integration, have attracted surprising attention for use in organic solar cells. In this review, we focus on the synthesis and applications of Se-containing conjugated polymers for organic solar cells and throughout compare them with S- and O-containing analogues where applicable. The relationships between the chemical structures and properties, such as absorptions, energy levels, mobilities, and photovoltaic behavior, are also discussed. 相似文献
The presence of in-homogeneity or defects in materials cannot be ignored. There is great need to understand the influence of defects on the mechanical response of nano-materials. In this study, atomistic simulations have been used to investigate the mechanical response of gold nano-wires under twisting. Simulations show that nano-wires have different elastic properties when defects are present. Embedded cracks of different sizes have been created in nano-wires to quantify in-homogeneity. The inter-atomic interactions are represented by employing an embedded-atom potential. The effect of different sizes of crack on potential energy, torque and stresses for investigating the mechanical response of a nano-wire is part of the whole investigation. It is predicted from our simulation that the presence of a crack and dimensions of the crack control the torsional response of gold nano-wires. Deviation in the behavior of gold nano-wires from continuum expectations is also discussed. The comparison of results of atomistic simulations is made with a linear elasticity model (of healthy and cracked nano-wires) to get deep insights into the nano-scale behavior of nano-wires. 相似文献
The possible mechanism of water transport from feed to osmotic agent side during forward osmosis in situation when feed contains high or low molecular weight compounds and their combination has been presented. The orientation of membrane was found to influence the transmembrane flux. When the feed contains mixture of low and high molecular weight compounds mode I (feed towards the support layer) was found to result in lower flux values as compared to Mode II (feed towards active layer) due to significant external concentration polarization. Forward osmosis resulted in the concentration of betalains content in beetroot juice and anthocyanin content in grape juice from 50.92 mg/L to 2.91 g/L (57.1 fold) and from 104.85 mg/L to 715.6 mg/L (6.8 fold), respectively. Total soluble solids in case of beetroot, grape and pineapple juice were found to increase from 2.3 to 52 °Brix, from 8.0 to 54.6 °Brix from 4.4 to 54 °Brix, respectively. 相似文献
Poly[3,4-(ethylenedioxy)thiophene] (PEDOT) nanocomposites (NCs) reinforced by varying titanium(IV)-doped iron(III) nano oxide (NITO) particles have been fabricated in dodecylbenzene sulphonic acid by in situ polymerization process using ammonium perdisulfate as initiator. The samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, electron microscopy, BET surface analysis etc. followed by subsequent evaluation of thermal properties, temperature-dependent 3D electrical transport. Thermal stability of the NCs increased with increasing NITO amount in PEDOT matrix. Electrical conductivity of the NCs increased significantly with increasing NITO content (0.45–67.73 S cm?1) and also with the temperature (50–300 K). 3D variable range hopping conduction mechanism explained the conduction pathways. Specific capacitance of NCs are enhanced with higher NITO content in polymer from 107 F g?1 (pristine PEDOT) to 158 F g?1 (NC) owing to the development of mesoporous (pore size: 4.1 nm and cylindrical pore volume: 0.103 cm3 g?1) structure and high specific surface area (~104 m2 g?1). 相似文献
Microsystem Technologies - This paper presents, the design and simulation of RF MEMS shunt capacitive switch. The electromechanical and electromagnetic analysis of the switch has been done using... 相似文献
Reversible Data hiding techniques reduce transmission cost as secret data is embedded into a cover image without increasing its size in such a way that at the receiving end, both secret data and the cover image can be extracted and recovered, respectively, to their original form. To further reduce the transmission cost, the secret data can be embedded in the compression codes by some popular reversible data hiding schemes. One of the popular and important reversible data hiding method is high- performance data-hiding Lempel–Ziv–Welch (HPDH-LZW) scheme which hides the secret data in LZW codes. In this paper, the HPDH-LZW scheme is modified in order to increase its hiding capacity and compression ratio. First, the proposed work modifies the Move to Front (MTF) encoding technique to hide the secret data and also to increase the similarity among the element of the cover media. Then, LZW encoding technique is applied on the resultant cover data to obtain LZW codes, which are used to hide further secret data. Experimental results show that the proposed scheme has significantly increased the data hiding capacity and have good embedding and extraction speed in comparison to other state of the art schemes.
Multimedia Tools and Applications - Computer-aided diagnosis (CAD) of schizophrenia based on the analysis of brain images, captured using functional Magnetic Resonance Imaging (fMRI) technique, is... 相似文献