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Optimizing nanoscale morphology and improving Carrier transport of PCDTBT-PCBM bulk heterojunction by cyclic carboxylate nucleating agents
摘要： In this work, four cyclic carboxylate commercial nucleating agents, bicyclo [2.2.1] heptane-2,3-dicarboxylic acid disodium salt (HPN-68L), sodium salt of hexahydrophthalic acid (HHPA-Na), sodium benzoate (Be-Na) and calcium salt of hexahydrophthalic acid (HPN-20E) were respectively added into poly[N-9’-heptadecanyl-2,7-carbazole-alt-5,5-(4’,7’-di-2-thienyl-2’,1’,3’ benzothiadi-azole)] (PCDTBT)-[6,6]-phenyl C61-butyric acid methyl ester (PCBM) blend. Atomic force microscopy (AFM) and UV-vis measurements indicate that the addition of carboxylic acid sodium salts can effectively optimize the morphology of active layer, decrease the phase domain size and increase the optical absorption intensity of PCDTBT-PCBM blends. The PCDTBT-PCBM-additive ternary devices were fabricated and found that adding carboxylic acid sodium salts can improve the hole mobility, balance the hole and electron mobility and finally increase the power conversion efficiency (PCE). Fixed the additive content as 5%, the modulation ability of the bicyclic dicarboxylic acid sodium salt HPN-68L is best, monocyclic dicarboxylic acid sodium salt HHPA-Na comes second, monocyclic carboxylic acid sodium salt Be-Na is worst. The addition of carboxylic acid calcium salt HPN-20E has no effects on the morphology and optical absorption intensity of the PCDTBT-PCBM blend, and the photoelectric properties of PCDTBT-PCBM-HPN-20E ternary device decreases in comparison with those of pristine PCDTBT-PCBM binary device. The modulation ability of cyclic carboxylate is related to its surface free energy and its location in the PCDTBT-PCBM blend. HPN-68L locates in the interfacial region between PCDTBT and PCBM, other cyclic carboxylates locates in the PCBM. Our finding suggests the addition of cyclic carboxylic acid sodium salts can be a facile approach to optimize the morphology and increase the electrical properties of organic materials for future development of organic photovoltaic devices.
关键词： PCDTBT-PCBM bulk heterojunction,carrier transport,organic photovoltaic devices,cyclic carboxylate nucleating agents,nanoscale morphology
更新于2025-09-09 09:28:46
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Formation Mechanisms of InGaAs Nanowires Produced by a Solid-Source Two-Step Chemical Vapor Deposition
摘要： The morphologies and microstructures of Au-catalyzed InGaAs nanowires (NWs) prepared by a two-step solid-source chemical vapor deposition (CVD) method were systematically investigated using scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). The detailed structural characterization and statistical analysis reveal that two specific morphologies are dominant in InGaAs NWs, a zigzag surface morphology and a smooth surface morphology. The zigzag morphology results from the periodic existence of twining structures, and the smooth morphology results from a lack of twining structures. HRTEM images and energy-dispersive X-ray spectroscopy (EDX) indicate that the catalyst heads have two structures, Au4In and AuIn2, which produce InGaAs NWs in a cubic phase crystalline form. The growth mechanism of the InGaAs NWs begins with Au nanoparticles melting into small spheres. In atoms are diffused into the Au spheres to form an Au-In alloy. When the concentration of In inside the alloy reaches its saturation point, the In precipitate reacts with Ga and As atoms to form InGaAs at the interface between the catalyst and substrate. Once the InGaAs compound forms, additional precipitation and reactions only occur at the interface of the InGaAs and the catalyst. These results provide a fundamental understanding of the InGaAs NW growth process which is critical to the formation of high-quality InGaAs NWs for various device applications.
关键词： HRTEM,Morphology,Formation mechanism,InGaAs nanowires,Microstructures
更新于2025-09-09 09:28:46
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Synthesis and Morphological Control of Mesoporous SiO2 with Cotton as Bio-Template
摘要： Mesoporous SiO2 with special short open axis-like morphology was successfully fabricated by using cotton fibers as bio-templates. Mesostructure and morphology of the samples were systematically studied by changing the cotton/SiO2 weight ratio and hydrothermal treating temperature. Textural property and morphology of the obtained mesoporous SiO2 were characterized by the combination of X-ray diffraction, N2 adsorption-desorption experiments and scanning electron microscope. Finally, batch adsorption of methylene blue was performed to detect the adsorption capacity of the cotton co-templated materials.
关键词： Cotton,SBA-15,Morphology control,Bio-template
更新于2025-09-09 09:28:46
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Incorporation of ZnO Nanostructures in MIS Architecture through Chemical Routes
摘要： Because it’s physical properties, ZnO is considered a potential semiconductor compound for fabricating electronic and optoelectronic functional devices. In this regard, several growth techniques have been developed in order to meet the requirements of commercial devices based in this material. On the pathway for improving the performance of the current devices, low-dimensional ZnO structures seem a promising alternative. Here, we report the process to obtain a metal-insulator-semiconductor (MIS) structure based on ZnO nanostructures grown on the surface of an anodized aluminum substrate (Al2O3/Al) by chemical routes.
关键词： SEM,morphology,MIS,ZnO,XRD
更新于2025-09-09 09:28:46
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LiDAR Validation of a Video-Derived Beachface Topography on a Tidal Flat
摘要： Increasingly used shore-based video stations enable a high spatiotemporal frequency analysis of shoreline migration. Shoreline detection techniques combined with hydrodynamic conditions enable the creation of digital elevation models (DEMs). However, shoreline elevations are often estimated based on nearshore process empirical equations leading to uncertainties in video-based topography. To achieve high DEM correspondence between both techniques, we assessed video-derived DEMs against LiDAR surveys during low energy conditions. A newly installed video system on a tidal flat in the St. Lawrence Estuary, Atlantic Canada, served as a test case. Shorelines were automatically detected from time-averaged (TIMEX) images using color ratios in low energy conditions synchronously with mobile terrestrial LiDAR during two different surveys. Hydrodynamic (waves and tides) data were recorded in-situ, and established two different cases of water elevation models as a basis for shoreline elevations. DEMs were created and tested against LiDAR. Statistical analysis of shoreline elevations and migrations were made, and morphological variability was assessed between both surveys. Results indicate that the best shoreline elevation model includes both the significant wave height and the mean water level. Low energy conditions and in-situ hydrodynamic measurements made it possible to produce video-derived DEMs virtually as accurate as a LiDAR product, and therefore make an effective tool for coastal managers.
关键词： erosion,beach morphology,video monitoring,Atlantic Canada,mobile terrestrial LiDAR,shoreline detection
更新于2025-09-09 09:28:46
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Purposive Assembling of Poly(3-hexylthiophene) onto Chemically Treated Multi-Wall Carbon Nanotube versus Reduced Graphene Oxide
摘要： Surfaces of multi-walled carbon nanotubes (CNTs) and reduced graphene oxide (rGO) nanosheets were chemically modified to design distinct donor-acceptor nano-hybrids having different morphologies and orientations. In unmodified CNTs and their derivatives functionalized with 2-hydroxymethyl thiophene (CNT-f-COOTh) and grafted with poly(3-dodecylthiophene) (CNT-g-PDDT), double-fibrillar, shish-kebab, and stem-leaf nanostructures were decorated. Furthermore, rGO nanosheets functionalized with 2-thiophene acetic acid (rGO-f-TAA) and grafted with poly(3-dodecylthiophene) (rGO-g-PDDT) were prepared to study differences in CNT and rGO supramolecules. Three types of orientations subsuming face-on, edge-on, and flat-on were detected in nano-hybrids based on CNT and rGO. Morphology (fibrillar) and orientation (face-on) of poly(3-hexylthiophene) (P3HT) assemblies were similar onto unmodified CNT and rGO nanostructures. Although patternings of P3HT chains were completely different onto functionalized CNT and rGO (shish-kebab versus nanocrystal decorated nanosheets), edge-on orientation was detected in CNT-f-COOTh/P3HT and rGO-f-TAA/P3HT nano-hybrids. In CNT-g-PDDT/P3HT and rGO-g-PDDT/P3HT systems, P3HT chains were extendedly assembled onto grafted carbonic materials; however, their different natures reflected stem-leaf and patched-like configurations, respectively. For unmodified, functionalized, and grafted CNT and rGO patterned with P3HT chains, a photoluminescence quenching was detected for a donor-acceptor nature. Owing to flat-on oriented P3HTs, the best photoluminescence quenching, thereby the best donating-accepting features were detected for CNT-g-PDDT/P3HT and rGO-g-PDDT/P3HT supramolecules.
关键词： donor-acceptor,morphology,rGO,nano-hybrid,CNT
更新于2025-09-09 09:28:46
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Low-temperature synthesis of potassium triniobate (KNb3O8) ceramic powder by a novel aqueous organic gel route
摘要： Potassium triniobate (KNb3O8) ceramic powder has been synthesized by a novel aqueous organic gel route relatively at low calcination temperature above 700 °C. Initially, homogeneous K-Nb precursor gels were prepared using the starting materials K-EDTA and Nb-citrate complex. Afterward, the mixture in stoichiometric ratio of K, Nb, and citric acid produced a pale yellow viscous like gel from which precursor powder was obtained after prolonged heating at 80 °C. The X-ray diffraction patterns reveal the formation of nearly single crystalline phase of KNb3O8 powder calcinated from 750 to 800 °C. Furthermore, the particle size of KNb3O8 powder is also estimated in the nano range using XRD data by the Debye-Scherrer formula. The microstructure, compositional homogeneity, and EDS analysis were performed by scanning electron microscopy that confirmed the fine, almost homogeneous agglomerate microstructure of synthesized ceramics. Thermal analysis showed about 90.3% weight loss of the precursor powder which was mainly responsible for the decomposition of the organic and some other substances. FTIR analysis ensured characteristic absorption bands for the formation of KNb3O8 ceramic powder.
关键词： Thermal analysis,KNb3O8 ceramic powder,Phase and morphology analysis,Aqueous organic gel method
更新于2025-09-09 09:28:46
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Reconstructing granular particles from X-ray computed tomography using the TWS machine learning tool and the level set method
摘要： X-ray computed tomography (CT) has emerged as the most prevalent technique to obtain three-dimensional morphological information of granular geomaterials. A key challenge in using the X-ray CT technique is to faithfully reconstruct particle morphology based on the discretized pixel information of CT images. In this work, a novel framework based on the machine learning technique and the level set method is proposed to segment CT images and reconstruct particles of granular geomaterials. Within this framework, a feature-based machine learning technique termed Trainable Weka Segmentation is utilized for CT image segmentation, i.e., to classify material phases and to segregate particles in contact. This is a fundamentally different approach in that it predicts segmentation results based on a trained classifier model that implicitly includes image features and regression functions. Subsequently, an edge-based level set method is applied to approach an accurate characterization of the particle shape. The proposed framework is applied to reconstruct three-dimensional realistic particle shapes of the Mojave Mars Simulant. Quantitative accuracy analysis shows that the proposed framework exhibits superior performance over the conventional watershed-based method in terms of both the pixel-based classification accuracy and the particle-based segmentation accuracy. Using the reconstructed realistic particles, the particle-size distribution is obtained and validated against experiment sieve analysis. Quantitative morphology analysis is also performed, showing promising potentials of the proposed framework in characterizing granular geomaterials.
关键词： Machine learning,Shape reconstruction,3D particle morphology,X-ray computed tomography,Level set
更新于2025-09-09 09:28:46
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Surface Morphology Effects on Photocatalytic Activity of Metal Oxides Nanostructured Materials Immobilized onto Substrates
摘要： Structure, shape and surface morphology of the material are directly determined by the substrate and growth method used for material fabrication of nanostructured metal oxides. Those characteristics play a crucial role in the photocatalytic activity of the material. This paper presents a short review of some of the most recent relevant publications regarding pure and doped nanostructured metal oxides used for photocatalytic applications focusing on the structure, shape and surface morphology of the material effects on photocatalytic activity. The cases of TiO2, ZnO and CuO metal oxides as well as various semiconductors and metal doping were reviewed. It was concluded that, according to the reviewed communications, the most important surface parameters affecting photocatalytic activity are surface area, surface to volume ratio, nanocrystallites size and crystallinity regardless the material. In particular, for each material, more surface parameters may be of significance.
关键词： Surface Morphology,Photocatalytic Activity,Metal Oxides
更新于2025-09-09 09:28:46
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Effect of Different Anions Upon the WO <sub/>3</sub> Morphology and Structure
摘要： In this study the effects of various anions (SO2? 4 , ClO? 4 and PO3? 4 ) were investigated on the hydrothermal treatment of WO3 from Na2WO4 and HCl at 180 and 200 °C. The products were analyzed by XRD and SEM. With the usage of SO2? 4 the obtained product was hexagonal (h-) WO3 in the form of nanorods at both temperatures. Applying ClO? 4 resulted in a mixture of WO3 · 0.33H2O and small amount of m-WO3 at 180 °C and pure WO3 · 0.33H2O at 200 °C. The morphology was consisted of cuboid shapes arranged into spherical structures at 180 °C and longitudinal ones at 200 °C. By the application of PO3? 4 no product formed at either temperature. Using the combination of SO2? 4 and ClO? 4 the product was h-WO3 at both 180 and 200 °C with rod-like crystals; thus, the effect of ClO? 4 was overdominated by the SO2? 4 ions. Utilization of PO3? 4 together with SO2? 4 , and/or ClO? 4 to the reaction mixture completely blocks the hydrothermal formation of solid products by forming water soluble phosphotungstic acids.
关键词： PO3? 4,Hydrothermal Treatment,SO2? 4,ClO? 4,Structure,Morphology,Tungsten Oxides
更新于2025-09-09 09:28:46