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New blue phosphorescence from trifluorosulfonyl-substituted iridium complexes
摘要： For color-pure phosphorescence organic light emitting diodes (PHOLEDs), we synthesized the trifluoromethyl sulfonyl substituted ligand and two new blue Iridium complexes with perfluoro-sulfonyl group (SOCF3pic and SOCF3mpic). The both iridium complexes showed similar photophysical and thermal properties while the HOMO energy leves of two Iridium complexes slightly differnet to be -5.84 eV for SOCF3pic and -5.74 eV for SOCF3mpic, respectively. The device with the SOCF3mpic dopant exhibited higher device efficiencies of 7.17 cd/A and 3.7 % compared to that with the SOCF3pic dopant (4.03 cd/A and 2.78 %). Two-dimensional GIXD images of scattered X-ray intensity from surface to full depth for SOCF3pic-doped and SOCF3mpic-doped TCTA:4PTPS films were characterized for preferential orientation along the out-of-plane direction.
关键词： preferential orientation along the out-of-plane direction,blue phosphorescence,iridium complex,grazing incidence wide-angle X-ray diffraction,organic light emitting diodes
更新于2025-09-23 15:23:52
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A Sensing Peak Identification Method for Fiber Extrinsic Fabry–Perot Interferometric Refractive Index Sensing
摘要： Chronic liver disease is a common cause of morbidity and mortality in the United States. The most common causes of liver disease include non-alcoholic fatty liver disease (NAFLD), chronic hepatitis C virus infection, alcoholic liver disease, and chronic hepatitis B virus infection. Through a discussion of various surveillance methods as well as their strengths and weaknesses, we review the epidemiology, risk factors, and natural history of each of these diseases and discuss prevention measures that have been effective in decreasing incidence rates.
关键词： Epidemiology,Hepatitis c,Liver diseases,Non-alcoholic fatty liver disease,Prevalence,Incidence,Hepatitis b,Alcoholic
更新于2025-09-23 15:23:52
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Characterization of the morphology of titanium and titanium (IV) oxide nanolayers deposited on different substrates by application of grazing incidence X-ray diffraction and X-ray reflectometry techniques
摘要： X-ray diffraction (XRD), grazing incidence X-ray diffraction (GIXRD) and X-ray reflectometry (XRR) techniques were applied for analysis of titanium (Ti) and titanium (IV) oxide (TiO2) nanolayers with thickness of 25 nm, 50 nm and 75 nm deposited on silicon, quartz and BK7 glass substrates. The aim of studies was investigating the crystal structure and morphology of the nanolayers in dependence on the substrate type. The chemical phases of nanolayers and substrates were determined by using the XRD and GIXRD measurements. The benefits of applying low angle GIXRD and XRR analytical techniques, both for substrate and nanofilm analysis, is discussed based on theoretical calculations and simulations. Additional, analytical capabilities of the XRR technique to nanolayer and substrate morphology analysis are presented. Simulated XRR curves for titanium (Ti) and titanium (IV) oxide nanolayers are discussed depending on the substrate type as well as the substrate and nanolayer roughnesses. Experimental reflectometry curves are presented for all titanium and titanium (IV) oxide nanolayers deposited on the different substrates. As the result of the XRR analysis, the nanolayer thickness and roughness together with substrate roughness are estimated. The mean values of the Ti and TiO2 layer thickness and roughness are presented for all studied samples. The largest roughness, both for nanolayers and for substrates, is obtained for BK7 glass material. In the manuscript, sample properties, experimental setups and measurement conditions are presented in details.
关键词： Titanium nanolayers,Titanium (IV) oxide nanolayers,Layer ion modification,X-ray reflectometry,Grazing incidence X-ray diffraction,Silicon, quartz substrates
更新于2025-09-23 15:22:29
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Incorporating Incidence Angle Variation into Sar Image Segmentation
摘要： We present a new approach for incorporating incidence angle derived synthetic aperture radar (SAR) brightness variation directly into SAR image analysis. This approach is unique in that the incidence angle dependency is modeled explicitly into the probability density function rather than an image-wide pre-processing ‘correction’. It can then be used for supervised and unsupervised image analysis, and is notably able to account for a different dependency rate for each class. This has potential benefits for wide-swath SAR imagery over flat areas and ocean, wide angled airborne and UAV based SAR data, connecting narrow-beam SAR images at different acquisition angles, as well as land-based analysis with local topographic terrain angles. An initial example demonstrates unsupervised image segmentation applied to sea ice mapping for meteorological services and climate science, and is compared to the same algorithm without the incidence angle modeling.
关键词： Terrain Correction,Sentinel-1,Wide-swath imagery,Synthetic Aperture Radar,Incidence Angle Correction
更新于2025-09-23 15:21:21
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Organic solar cells probed with advanced neutron scattering techniques
摘要： Neutron scattering techniques provide unique insights into the active layer morphology of organic solar cells. The nanoscale morphology, the thin film vertical composition, and the intermixing on a molecular level, which all strongly have an impact on the performance of organic solar cells, can be probed with neutrons. In addition to the static structure, also fast dynamics occurring in the active material is accessible with neutrons. This perspective letter highlights the power of grazing incidence small angle neutron scattering and quasi-elastic neutron scattering experiments after shortly introducing into the working principle of organic solar cells.
关键词： neutron scattering,grazing incidence small angle neutron scattering,morphology,quasi-elastic neutron scattering,organic solar cells
更新于2025-09-23 15:21:01
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Binary Superlattices of Infrared Plasmonic and Excitonic Nanocrystals
摘要： Self-assembled superlattices of nanocrystals offer exceptional control over the coupling between nanocrystals, similar to how solid-state crystals tailor the bonding between atoms. By assembling nanocrystals of different properties (e.g., plasmonic, excitonic, dielectric, or magnetic), we can form a wealth of binary superlattice metamaterials with new functionalities. Here, we introduce infrared plasmonic Cu2?xS nanocrystals to the limited library of materials that have been successfully incorporated into binary superlattices. We are the first to create a variety of binary superlattices with large excitonic (PbS) nanocrystals and small plasmonic (Cu2?xS) nanocrystals, both resonant in the infrared. Then, by controlling the surface chemistry of large Cu2?xS nanocrystals, we produced structurally analogous superlattices of large Cu2?xS and small PbS nanocrystals. Transmission electron microscopy (TEM) and grazing-incidence small-angle X-ray scattering (GISAXS) were used to characterize both types of superlattices. Furthermore, our unique surface modification of the large Cu2?xS nanocrystals also prevented them from chemically quenching the photoluminescence of the PbS nanocrystals, which occurred when the PbS nanocrystals were mixed with unmodified Cu2?xS nanocrystals. These synthetic achievements create a set of binary superlattices that can be used to understand how infrared plasmonic and excitonic nanocrystals couple in a variety of symmetries and stoichiometries.
关键词： infrared quantum dots,nanocrystals,self-assembly,supracrystal,metamaterial,binary superlattice,grazing-incidence small-angle X-ray scattering (GISAXS)
更新于2025-09-23 15:21:01
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Characterization of Lattice Parameters Gradient of Cu(In1-xGax)Se2 Absorbing Layer in Thin-Film Solar Cell by Glancing Incidence X-Ray Diffraction Technique
摘要： In or Ga gradients in the Cu(In1-xGax)Se2 (CIGS) absorbing layer lead to change the lattice parameters of the absorbing layer, giving rise to the bandgap grading in the absorbing layer which is directly associated with the degree of absorbing ability of the CIGS solar cell. We tried to characterize the depth profile of the lattice parameters of the CIGS absorbing layer using a glancing incidence X-ray diffraction (GIXRD) technique, and then allows to determine the In or Ga gradients in the CIGS absorbing layer, and to investigate the bandgap grading of the CIGS absorbing layer. When the glancing incident angle increased from 0.50 to 5.00°, the a and c lattice parameters of the CIGS absorbing layer gradually decreased from 5.7776(3) to 5.6905(2) ?, and 11.3917(3) to 11.2114(2) ?, respectively. The depth profile of the lattice parameters as a function of the incident angle was consistent with vertical variation in the composition of In or Ga with depth in the absorbing layer. The variation of the lattice parameters was due to the difference between the ionic radius of In and Ga co-occupying at the same crystallographic site. According to the results of the depth profile of the refined parameters using GIXRD data, the bandgap of the CIGS absorber layer was graded over a range of 1.222 to 1.532 eV. This approach nondestructively guess the bandgap depth profile through the refinement of the lattice parameters using GIXRD data on the assumption that the changes of the lattice parameters or unit-cell volume follow a good approximation to Vegard’s law.
关键词： Vegard’s law,Cu(In1-xGax)Se2 absorbing layer,Depth profile,Bandgap grading,Glancing incidence X-ray diffraction technique
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Angular Dependence of Textured Bifacial Silicon Heterojunction Solar Cells for High Latitudes
摘要： Bifacial photovoltaics at high latitudes can achieve up to 25-45% bifacial gain due to high-albedo snow cover and high proportion of diffuse light. We studied the angular performance of bifacial silicon heterojunction solar cells with various textures to understand high-latitude effects on optical losses. For cone and pyramid-patterned designs, efficiency decreases at high angles, primarily due to increased reflectivity, although longer path length through front-surface films also increases UV losses for all surface types. At 80° incidence and 25°C, a <7% reduction in short-circuit current due to change in external quantum efficiency is observed for random pyramid textured surfaces. Simulation is compared to measured external quantum efficiency for a silicon heterojunction cell, and similar trends are observed with increasing angle of incidence. A relative reduction of <1% in short-circuit current is also observed when moving from an air mass of 1.5 to 5 at high angles of incidence. These results will inform future solar heterojunction designs for this application and be applied to refine annual energy yield calculations.
关键词： photovoltaic cells,bifacial photovoltaics,indium-tin-oxide,amorphous silicon,ray tracing,silicon solar cell,texture,angle of incidence,heterojunction cell,air mass
更新于2025-09-23 15:19:57
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Interfacial engineering and film-forming mechanism of perovskite films revealed by synchrotron-based GIXRD at SSRF for high-performance solar cells
摘要： Organic-inorganic hybrid perovskites as promising light-harvesting materials have been the focus of scientific research and development of photovoltaics recently. Especially, metal halide perovskites currently become one of the most competitive candidates for the fabrication of solar cells with record certified efficiency over 25%. Despite the high efficiency, many fundamental questions remain unclear and need to be addressed at both the material and device levels, such as weaker stability, poorer reproducibility, easier degradation influenced by water, oxygen, thermal factors, and so on. Based on recent reports, interfacial engineering plays a crucial role in controlling the behavior of the charge carriers and in growing high quality, defect-free perovskite crystals, therefore helping to enhance device performance and operational stability. However, little attention has been paid to the interface interaction mechanism among carrier transport layers and perovskite active layer. It is extremely urgent to explore the perovskite interfaces in details and to find out how its interface structure is relative to the efficiency and hysteresis in perovskites solar cells. Based on the Shanghai Synchrotron Radiation Facility (SSRF), we have established an advanced perovskite photovoltaic device preparation and in-line test system, developed a series of unique surface diffraction analysis methods based on ex situ and in situ grazing incidence X-ray diffraction (GIXRD), and reported a large number of novel synchrotron radiation results on crystallization of the perovskite photovoltaics films. Our main investigations are aimed to deeply in-situ study the perovskite film growth dynamics using synchrotron radiation GIXRD technology in combination with a customized mini online glove box (c(H2O,O2)<1 ppm) and temperature-humidity control equipment, and so on., which should provide solid theoretical background and point to the useful direction for designing and fabricating high-performance perovskites solar cells. Moreover, a multi-functional joint characterization technology that in-situ GIXRD simultaneously combines with conventional characterization methods at synchrotron radiation beamline station must be put on the agenda in future research, which greatly promotes much more comprehensive and intuitive understanding of the nucleation, microcrystallization, and degradation mechanisms of perovskite heterojunction films, and therefore further optimizing their chemical synthesis strategies at the molecular level for functional materials.
关键词： Growth dynamics,Perovskites solar cells,Device performance,Grazing incidence X-ray diffraction,In-situ study
更新于2025-09-23 15:19:57
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Dynamics of Instability in Plasmonic Response of Nanostructured Gold Thin Films on Ambient Ageing
摘要： Instability in the plasmonic response of nanostructured gold (Au) thin films on ambient ageing has been investigated. Different types of Au nanostructures (island, percolated, and continuous thin film) are obtained at the early stage of thin film growth by variation in film thickness using sputtering technique. Absorbance spectra of as-deposited island Au film shows a systematic blue-shift in the localized surface plasmon resonance (LSPR) peak position on ageing. The rate of blue-shift in the LSPR peak position is fitted with single-exponential decay function to analyze the dynamics of the plasmonic response. The as-deposited percolated Au film displays a transformation of broadened plasmonic response into a wavelength independent absorbance profile on ageing. The immersion of a new plasmonic band in the absorbance spectra is noted for continuous Au thin film on ageing. The change in plasmonic responses of nanostructured Au thin films on ambient ageing is found to be directly correlated with the re-organization of the surface morphology. Finally, ageing-induced solid-state dewetting and crystallization are found to be the main responsible processes of the underlying mechanism for morphological re-organizations, leading to change in the plasmonic response of the nanostructured Au thin films.
关键词： X-ray reflectivity,Grazing incidence X-ray diffraction,Localized surface plasmon resonance,Thin film ageing,Transmission electron microscopy
更新于2025-09-23 15:19:57