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- 2019
- 2018
- solution deposition
- printable electronic transport layer
- multilayer OLEDs
- fully inkjet printed
- terahertz
- vector fitting
- impedance
- multilayer graphene
- Optoelectronic Information Science and Engineering
- Shenzhen China Star Optoelectronics Semiconductor Display Technology Co., Ltd.
- Nanjing University of Posts and Telecommunications
- Peking University
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Multilayer plasmonic photonic structures embedding photochromic molecules or optical gain molecules
摘要： We study the optical properties of different functional molecular systems in order to embed them in properly designed photonic structures for photochromic switching and lasing. We study the light absorption of two photochromic molecules and of 4,4’-bis[(N-carbazole)styryl]biphenyl (BSB-Cz) with density functional theory. For the photochromic diarylethene we derivate the refractive index with Kramers-Kronig relations and we design multilayer photonic structures alternating diarylethene with either poly vinyl carbazole or fluorine indium co-doped cadmium oxide (FICO) nanoparticle-based layers. For BSB-Cz we design a one-dimensional photonic crystal alternating BSB-Cz layers wit SiO2 layers and a microcavity embedding BSB-Cz between indium tin oxide (ITO) / FICO nanoparticle-based multilayers.
关键词： multilayer plasmonic photonic structures,photochromic molecules,density functional theory,Kramers-Kronig relations,optical gain molecules
更新于2025-09-23 15:19:57
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Wide-range line shape control of Fano-like resonances in all-dielectric multilayer structures based on enhanced light absorption in photochromic waveguide layers
摘要： We have succeeded in controlling the line shape of Fano-like resonances in all-dielectric multilayer structures in a wide range by UV light irradiation. Multilayer structures consisting of a waveguide layer supporting a half-leaky guided mode, a spacer layer, and another waveguide layer supporting a planar waveguide mode are known to exhibit Fano-like line shapes in attenuated total reflection spectra due to coupling between the half-leaky guided mode and the planar waveguide mode. Using a photochromic layer, i.e., a layer doped with spiropyran molecules, as one of the waveguide layers, we controlled the amount of light absorption in the waveguide layer by varying the UV irradiation dose. We demonstrated that the line shape changes dramatically depending on the UV dose, from the electromagnetically induced transparency-like to electromagnetically induced absorption-like line shape (or vice versa) passing through the Fano-like line shape. We also demonstrated that the photochromic response induced by UV irradiation in the Fano-resonant multilayer structure is enhanced by a factor of ～100 relative to that in a single photochromic layer. Our analyses based on electromagnetic calculations suggest that the dramatic line shape change and the enhanced photochromic response are the consequences of enhanced local electric fields inside the photochromic waveguide layer combined with the photoinduced increase in the imaginary part of the dielectric constant.
关键词： electromagnetically induced transparency,all-dielectric multilayer structures,Fano-like resonances,UV light irradiation,electromagnetically induced absorption,photochromic waveguide layers
更新于2025-09-23 15:19:57
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Complex Bianisotropy Effect on the Propagation Constant of a Shielded Multilayered Coplanar Waveguide Using Improved Full Generalized Exponential Matrix Technique
摘要： A theoretical study of the electromagnetic propagation in a complex medium suspended multilayer coplanar waveguide (CPW) is presented. The study is based on the generalized exponential matrix technique (GEMT) combined with Galerkin’s spectral method of moments applied to a CPW printed on a bianisotropic medium. The analytical formulation is based on a Full-GEMT, a method that avoids usual procedures of heavy and tedious mathematical expressions in the development of calculations and uses matrix-based mathematical expressions instead. These particularities are exploited to develop a mathematical model for the characterization of wave propagation in a three-layer shielded suspended CPW structure. This study is based on the development of mathematical formulations in full compact matrix-based expressions resulting in Green’s functions in a matrix form. The implemented method incorporates a new accelerating procedure developed in the GEMT which provides an initial value used to speed up searching for the exact solution in the principal computation code. This helped us to obtain accurate solutions with tolerable computing time. Good agreements have been achieved with the literature in terms of accuracy and rapid convergence. The results for di?erent cases of bianisotropy have been investigated, and particularly, the e?ect on the dispersion characteristics is presented and compared with the isotropic case.
关键词： Muller’s method,dispersion characteristics,chiral,acceleration procedure,complex propagation constant,full-GEMT,multilayer CPW structure,Tellegen
更新于2025-09-23 15:19:57
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Prediction of Ia??V Characteristic Curve for Photovoltaic Modules Based on Convolutional Neural Network
摘要： Photovoltaic (PV) modules are exposed to the outside, which is affected by radiation, the temperature of the PV module back-surface, relative humidity, atmospheric pressure and other factors, which makes it difficult to test and analyze the performance of photovoltaic modules. Traditionally, the equivalent circuit method is used to analyze the performance of PV modules, but there are large errors. In this paper—based on machine learning methods and large amounts of photovoltaic test data—convolutional neural network (CNN) and multilayer perceptron (MLP) neural network models are established to predict the I–V curve of photovoltaic modules. Furthermore, the accuracy and the fitting degree of these methods for current–voltage (I–V) curve prediction are compared in detail. The results show that the prediction accuracy of the CNN and MLP neural network model is significantly better than that of the traditional equivalent circuit models. Compared with MLP models, the CNN model has better accuracy and fitting degree. In addition, the error distribution concentration of CNN has better robustness and the pre-test curve is smoother and has better nonlinear segment fitting effects. Thus, the CNN is superior to MLP model and the traditional equivalent circuit model in complex climate conditions. CNN is a high-confidence method to predict the performance of PV modules.
关键词： convolutional neural network,photovoltaic module,current–voltage curve,multilayer perceptron
更新于2025-09-23 15:19:57
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Machine learning-based mapping of micro-topographic earthquake-induced paleo Pulju moraines and liquefaction spreads from a digital elevation model acquired through laser scanning
摘要： The advent of public open source airborne laser scanning-produced digital elevation models (ALS DEM) has provided new perspectives on glacial geomorphology in the Nordic countries. Seismically-induced micro-topographic paleo-landforms can now be identified and mapped throughout the former Fennoscandian Ice Sheet, allowing spatial safety assessment for nuclear waste disposal. Automated machine learning techniques enable recognition of these fine-scale geomorphological features efficiently and in a consistent way nationwide. The current study focuses on automated recognition of paleo liquefaction spreads and Pulju moraines in northern Finland. Geomorphometric variables in different cell sizes were first derived from the 2 m ALS DEM by Gabor and principal curvature filtering to emphasize the elevational multi-scale texture of these paleo-seismic landforms. The Gabor textural variables were considered as a baseline method and the principal curvature features, including maximum and minimum curvature, were used because they have previously been proven critical in recognition of concave and convex elongated features. Both sets of raster variables were then turned into histogram-based features and input into a non-linear supervised multilayer perceptron early-stop committee which is a neural network classifier. The leave-one-out cross-validation performance results indicated principal curvature features to be highly successful with 94% accuracy. Principal curvatures provided a clear improvement to Gabor based features which provided significantly lower accuracies between 83?85%. The study demonstrates the high success of supervised neural network-based classification of ALS DEM data and derived textural features capturing the multi-scale nature of the micro-topographic liquefaction spreads and Pulju moraines. The approach could be utilized for time-efficient mapping of these paleo-seismic geomorphologies to complete paleo-seismic databases in formerly glaciated regions.
关键词： rotation invariant,histogram-based features,leave-one-out cross-validation,principal curvature,area invariant,multilayer perceptron,landforms,paleo-seismology,geomorphology,Gabor filter,Pulju moraine,liquefaction spreads
更新于2025-09-23 15:19:57
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Double-mode absorption in double-defect photonic crystal with one graphene multilayer
摘要： In order to realize the double-mode absorption, double-defect photonic crystal is formed. For the upper defect, the graphene multilayer is placed on the top of photonic crystal acting as the surface defect, while for the one below, the pure dielectric destroying the periodicity of photonic crystal services as the internal defect. Depending on FP resonance, two modes achieve perfect absorption at critical coupling. Merely, the mode-dependences are different, so that these modes have different distinctly Q factors and can be tuned independently by changing the chemical potential of graphene and the size of defect. Combining the angle response, the independence-tuning of modes becomes more flexible. Besides, both of modes’ frequencies and amplitudes are enslaved to the layer number of graphene. And the period of photonic crystal affects directly the peak–peak distance and modes number.
关键词： Double-mode absorption,Double-defect photonic crystal,FP resonance,Critical coupling,Graphene multilayer
更新于2025-09-23 15:19:57
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Beryllium-Based Multilayer Mirrors and Filters for the Extreme Ultraviolet Range
摘要： This paper presents the first results of systematic studies of beryllium as a material for multilayer mirrors (MLM) and transmission filters (TF) for the EUV spectral range. The objective for the study is the need for the increase in reflectivity and spectral resolution of MLMs for studying the Sun's corona. We investigated Mo/Be (working wavelength is 13.2 nm), Be/Al and Be/Si/Al (17.1 and 30.4 nm) multilayers, as well as free-standing Be films. It was shown that the Be-containing MLMs have significant advantage in reflectivity while their spectral pass-band is similar to beryllium-free MLMs. Observation of the MLMs in the course of 20 months has not revealed any significant decrease in the reflection coefficient. Effect of the silicon interlayers on reflectance of Be/Al MLM is explained. Investigation of a free-standing beryllium filter of the 160 nm thickness showed that its mechanical strength is approximately at the same level as that of the aluminum filter with the same thickness. There is also high stability of the transmittance.
关键词： Multilayers,Multilayer Design,X-ray Mirrors,Space Optics
更新于2025-09-19 17:15:36
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A single light spot GC detector employing localized surface plasmon resonance of porous Au@SiO <sub/>2</sub> nanoparticle multilayer
摘要： This paper describes the synthesis of a nano-porous multilayered film consisting of Au@SiO2 nanoparticles. This film was used to miniaturize the size of a localized surface plasmon resonance (LSPR)-based capillary gas chromatograph (GC) detector. A layer-by-layer (LbL) approach with proper surface reaction sequences was used to create a multilayer structure that consisted of as many as five layers of Au@SiO2 nanoparticles. The center wavelength of LSPR was shifted from 520 to 634 nm due to the approximation of additional layers of nanoparticles. The vapor response time for this Au@SiO2 multilayer LSPR sensor was identical to that of an Au nanoparticle monolayer, which confirmed that this multilayer structure has a high level of gas permeability. The multilayer was synthesized inside a glass capillary for use as a GC detector. Due to the enhancement of absorbance, the gas chromatographic signal was obtained via a single spotlight that penetrated one side of the glass capillary and was then reflected by a silver mirror coated on the opposite side. The detection limits were ≤20 ng for cyclohexanone and m-xylene.
关键词： gas chromatography,localized surface plasmon resonance,multilayer film,miniaturization,Au@SiO2 nanoparticles,VOC detection
更新于2025-09-19 17:15:36
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Optimized properties of innovative ElectroChromic Device using ITO / Ag / ITO electrodes
摘要： The "Dielectric/Metal/Dielectric" (DMD) stacked films being used as transparent and conductive (TC) electrodes, have demonstrated excellent application in the ElectroChromic (EC) process and devices. In this work, multilayers (IAI) made of 50 nm of Indium Tin Oxide (ITO) / 5 nm of metallic silver (Ag) / 30 nm of ITO that exhibit band-gap, low resistance of 7.4 ? and the high figure of merit of 9.9×10-3 ?-1 were introduced in a complete five-layer Glass / IAI / NiOx / LiClO4-PC-PMMA / WO3 / IAI / Glass ElectroChromic Device (ECD). The single IAI electrode as well as the two actives EC layers Glass / IAI / NiOx and Glass / IAI / WO3 were firstly characterized for their TC and EC properties respectively. Then, the EC properties of the complete five-layer ECD were analyzed. Fast response time (2.02 s for the bleaching and 2.25 s for complete coloration), wide optical modulation in the visible light region (~55% at 550 nm), long lifetime (more than 6000 s), large capacity and good stability as well as high coloration efficiency (31.7 cm2 C–1) were obtained. The improved EC performance of ECD were related to the good electrical and optical properties of IAI electrode.
关键词： Electrochromic characteristics,Electrochromic devices,Multilayer,Polymer gel electrolyte,Transparent conductive materials
更新于2025-09-19 17:15:36
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Effect of two-step post-treatment on optical properties, microstructure, and nanosecond laser damage threshold of HfO <sub/>2</sub> /TiO <sub/>2</sub> /SiO <sub/>2</sub> multilayer high reflection films
摘要： HfO2/TiO2/SiO2 periodic multilayer high reflection films deposited by an electron beam are post-treated by two-step post-treatment and thermal annealing post-treatment, respectively. The optical properties, microstructures, surface morphologies, and laser-induced damage threshold (LIDT) of the films are studied comparatively. The results show that the two-step post-treatment enhances the high reflection films’ density and reduces the film surface roughness and the defects of the film. The test results show that the LIDT of HfO2/TiO2/SiO2 high reflection films treated by two-step post-treatment reaches 32.8 J/cm2, which is 110.26% higher than that of the untreated film. Compared with the HfO2/TiO2/SiO2 high reflection films after thermal annealing post-treatment, the LIDT increased nearly 27.6% after two-step post-treatment. Two-step post-treatment of high reflection films can effectively remove the defects on the surface of the film, reduce the oxygen vacancies inside the film, and further increase the laser damage threshold of the high reflection films.
关键词： laser-induced damage threshold,HfO2/TiO2/SiO2,two-step post-treatment,thermal annealing,multilayer high reflection films
更新于2025-09-19 17:13:59