Wafer-scale plasmonic metal-dielectric-metal structural color featuring high saturation and low angular dependence

Structural color has been studied through various methods due to its distinguished features of stability, durability, high information storage density and high integration. However, the artificial structural color samples do not exhibit superior performance in color saturation and low angular dependence. Here, we present an approach to acquire additive reflective color based on a metal-dielectric-metal (MDM) stack. The upper layer composed of Ag particles is perforated in a hexagonal arrangement which profits from the dielectric anodic aluminum oxide (AAO) membrane, the size and shape of the Ag particles are getting inhomogeneous as the deposition thickness of the upper layer increasing, which expands the desired absorption range of surface plasmons. The residual non-anodized Al foil serves as a highly reflective substrate for efficient color presenting through the thin-film interference in this plasmonic MDM system. As a result, the color gamut area of this MDM stack is extended 8 times in CIE chromaticity coordinates. Finally, a wafer-scale (diameter of 83 mm) badge of Harbin Engineering University (HEU) with highly saturated colors and a pattern characterized with low angle-dependent property (up to 60°) are presented, which exhibit promising prospects in commercial coloring and imaging.

New Multicolor Tungstate-Molybdate Microphosphors as an Alternative to LED Components

Due to the ongoing need to create phosphors with the appropriate emission color for the production of light emitting diodes, we decided to synthesize a series of multicolour microphosphors with tunable visible emissions, depending on the composition of dopant ions. In this work, we investigated the structure, morphology, and luminescent properties of new molybdate–tungstate phosphors co-doped with Tb3+ and Eu3+ ions. The conventional high temperature solid state method was used to prepare a series of CaMoyW1−yO4:Eu3+x/Tb3+1−x materials. In order to obtain phosphors with the most promising luminescent properties, the experiment was planned by taking into account the different composition of the matrix and the concentration of the particular dopant ions (Eu3+x/Tb3+1−x, x = 0.001, 0.003, 0.005, 0.007, 0.009). As a result, luminescent materials were obtained with a pure tetragonal crystal structure, the space group of I41/a, confirmed by X-ray diffraction (XRD). The size and shape of the particles obtained from the materials were analyzed based on scanning electron microscopy images. Luminescence spectroscopy (excitation and emission spectra, decay lifetimes) was utilized to characterize the luminescence properties of the as-prepared phosphors. The color change of the emission from green-yellow to orange-red was confirmed using the 1931 Comission Internationale de l’Eclairage (CIE) chromaticity coordinates and color correlated temperature (CCT).

White-Light-Emitting Control via Lead-free Perovskite Material

In recent years, the emerging lead-free halide perovskites are attracting great attention in the field of the optical detection and luminescence due to its inherent strong light absorption and high balanced carrier on transmission characteristics. This experiment attempts to explore the way of grinding to prepare the white light emitting materials that does not contain lead. Low dimensional lead-free copper-based halide luminescent materials are prepared by controlling the molar ratio of a series of lead-free perovskite materials Cs3Cu2I5 and CsCu2I5. As-synthesized powder samples are characterized by powder X-ray diffraction (XRD), photoluminescence spectrum (PL), photoluminescence excitation spectrum (PLE) and photoluminescence quantum yield (PLQY) and other characterization methods. We successfully prepare the white powder sample by controlling the molar ratio of reactants (CsI:CuI=1:3). We measure the Commission Internationale de l’Eclairage (CIE) chromaticity coordination of PL spectra for the samples which can be regulated by the ratio of reactants. Moreover, it is demonstrated that acetone can effectively promote the reaction of reactants. These findings make this material be a stable and environmentally friendly white luminescent material, which has the potential to be used in white LED applications.

An Explanation of Subsurface Optical Pathways through Food Myosystems and their Effect on Colorimetry

Light may pass along and across the long axes of muscle fibers in any food myosystem. Thus, incident light may be scattered in several ways before some of it reappears at the surface as diffuse reflectance. Pathways may be short if scattering is strong, or long if scattering is weak. Short pathways minimize selective absorbance by chromophores such as myoglobin, while long pathways maximize selective absorbance. Many food myosystems exhibit a post-mortem decrease in pH caused by anaerobic glycolysis with a series of microstructural changes – glycogen granules between myofibrils are lost, myofibrils shrink laterally as myofilaments move closer together, water moves from within myofibrils to the space between them, muscle fiber membranes leak and lose their electrical capacitance, and myoglobin is flushed into the fluid filled spaces between muscle fibers. These changes increase scattering of light passing across the long axes of muscle fibers. Scattering of light along muscle fibers is caused by sarcomere discs (A-bands). Interference from one or a small number of sarcomere discs may cause iridescence, but in most cases interference from numerous discs causes achromatic diffuse reflectance. Commission International de l’Éclairage (CIE) chromaticity coordinates were calculated for various subsurface optical pathways. Pathways across versus along muscle fibers had a strong effect on CIE y (r = 0.84, P < 0.01) and an even stronger effect on CIE Y% (r = 0.95, P < 0.005).

Spectroscopic Properties of Alumina Borosilicate Glassesw Alkaline Oxides Doped with Sm2O3 for Display Laser Emission

This research investigates the influence of the concentration of Sm+ 3 ions on the features of a new borosilicate glass system with the composition 50B2O3– 14SiO2- 20Li2O– 15Na2O– 1.0Al2O3-x(Sm2O3), where x = 100, 200, 300, 400, and 500 ppm. The glasses are characterized by XRD, FTIR, UV- Vis- NIR, and photoluminescence spectra. The XRD results proved that all prepared glass has amorphous nature. Moreover, it was found that the value of density, ρ, and refractive index,n, increase with increasing of Sm+ 3 content. Otherwise, the value of molar volume, optical energy gap, and boron-boron distance decrease by increasing sm+ 3 concentration. The structure of glasses studied was investigated by computing \(Internuclear \left({r}_{i}\right)\), Polaron radius \(\left({r}_{p}\right)\), field strength \(\left(F\right)\) and the deconvolution of FTIR spectra. Judd-Ofelt theory applied to clarify the structural changes and nature of the bonds of prepared glasses. Moreover, A spectroscopic quality factor, the branching ratio (βr), and lifetime (τ) are calculated via the parameters of Judd-Ofelt. The color chromaticity of the present glasses evidenced that the emission was in the white-reddish orange region under 402nm excitation depended on the concentration of Sm3+ ions incorporated into the host glasses. From photoluminescence emission, stimulated emission cross-section, and CIE chromaticity leads to these glasses are promising for light-emitting diode (LED) as; laser material in a wide range.

Synthesis and Characterization of a Novel Sm+3 Activated NaCdVO4 Phosphors for Red Emitting Material

Sm3+ activated NaCdVO4 phosphors were prepared by the simple solid-state reaction method. X-ray diffraction, dispersive energy (EDS), scanning electron microscope (SEM), infrared as well as photoluminescence (PL) techniques were used to characterize obtained samples. Irregular and non-uniform structures were observed by SEM. EDS spectra confirmed the presence of Na, Cd, V, O and Sm elements in each sample. Uuder 405nm excitation, the NaCd1 − xVO4: xSm (x = 0.01, 0.03 and 0.05) exhibits a bright red emission consisting mainly of four wavelength peaks at 556, 593, 650 and 700 nm. The highest emission intensity was found with a composition of x = 0.05. The analysis of PL spectra suggest that studied samples can be used as a red emitting phosphors candidates for fabrication of white LEDs. The CIE chromaticity coordinates of prepared samples were close to the blue-emitting phosphors for NaCdVO4 and red-emitting ones for NaCd0.99Sm0.01VO4, NaCd0.97Sm0.03VO4, and NaCd0.95Sm0.05VO4. The band gap energies of phosphors were calculated from reflectance data using K-M function.

Design and fabrication of a semi-transparent solar cell considering the effect of the layer thickness of MoO3/Ag/MoO3 transparent top contact on optical and electrical properties

We conducted the present study to design and manufacture a semi-transparent organic solar cell (ST-OSC). First, we formed a transparent top contact as MoO3/Ag/MoO3 in a dielectric/metal/dielectric (DMD) structure. We performed the production of an FTO/ZnO/P3HT:PCBM/MoO3/Ag/MoO3 ST-OSC by integrating MoO3/Ag/MoO3 (10/$$d_{m}$$ d m /$$d_{{od}}$$ d od nm) instead of an Ag electrode in an opaque FTO/ZnO/P3HT:PCBM/MoO3/Ag (–/40/130/10/100 nm) OSC, after theoretically achieving optimal values of optical and electrical parameters depending on Ag layer thickness. The transparency decreased with the increase of $$d_{m}$$ d m values for current DMD. Meanwhile, maximum transmittance and average visible transmittance (AVT) indicated the maximum values of over 92% for $$d_{m} ~$$ d m = 4 and 8 nm, respectively. For ST-OSCs, the absorption and reflectance increased in the visible region by a wavelength of longer than 560 nm and in the whole near-infrared region by increasing $$d_{m}$$ d m up to 16 nm. Moreover, in the CIE chromaticity diagram, we reported a shift towards the D65 Planckian locus for colour coordinates of current ST-OSCs. Electrical analysis indicated the photogenerated current density and AVT values for $$d_{m} = 6$$ d m = 6 nm as 63.30 mA/cm2 and 38.52%, respectively. Thus, the theoretical and experimental comparison of optical and electrical characteristics confirmed that the manufactured structure is potentially conducive for a high-performance ST-OSC.

Effects of Bi3+ Ion-Doped on the Microstructure and Photoluminescence of La0.97Pr0.03VO4 Phosphor

The objective of this paper is to enhance the emission intensity of La0.97Pr0.03VO4 single-phased white light emitting phosphor. The Bi3+ ion-doped La0.97Pr0.03VO4 single-phased white light emitting phosphors are synthesized using a sol-gel method. The structure and photoluminescence properties of (La0.97-yBiy)Pr0.03VO4 (y = 0-0.05) phosphor are also examined. The XRD results show that the structure of La0.97Pr0.03VO4 phosphors with different concentrations of Bi3+ ion doping keeps the monoclinic structure. The SEM results show that the phosphor particles become smoother when the Bi3+ ion is doped. The excitation band for La0.97Pr0.03VO4 phosphor exhibits a blue shift from 320 nm to 308 nm as the Bi3+ ion contents are increased. The maximum emission intensity is achieved for a Bi3+ ion content of 0.5 mol%, which is about 30% greater than that with no Bi3+ ion doped. The CIE chromaticity coordinates are all located in the near white light region for different Bi3+ ion-doped La0.97Pr0.03VO4 phosphors.

Luminescence Studies of Transition Metal (Cu+ and Ag+ Ions) Activated Alkali Zinc Mixed Phosphate

Because of the importance of inorganic phosphates in the solid-state lighting industry, KZnPO4 doped with some transition metal dopant ions like Cu+ and Ag+ ions were prepared by low-cost co-precipitation method at room temperature followed by annealing at a high temperature around 6500C. The prepared phosphors were characterized by X-ray diffraction. In the case of a Photoluminescence study for KZnPO4 doped with Cu+, the emission was observed at 425 nm, which corresponds to the emission of Cu+ ion. In the case of Ag+ doped KZnPO4, weak emission was observed at 420 nm, which is assigned to the emission of Ag+ ions. CIE chromaticity coordinate of KZnPO4 doped with Cu+ and Ag+ ions phosphor was also evaluated via using OSRAM SYLVANIA color calculator and colour purity of concentration was nearly 95% of Cu+ and Ag+ ions. The obtained outcomes revealed that the prepared phosphor shows potential application in the field of solid-state lighting.

Y2O3:Eu3+ Nanophosphor-Coated Mica or TiO2/Mica as Red-Emitting Pearl Pigment: Coating Factors, Luminescent and Gloss Properties

Red-emitted Y2O3:Eu3+ nanophosphor coated on a mica flake (Y2O3:Eu@MF) or on TiO2 having a rutile crystalline mica flake (Y2O3:Eu@TMF) has been prepared by an electrostatic interaction with the wet-coating method for the purpose of a pigment with luminescent and gloss properties. Aggregated Y2O3:Eu3+, prepared by the template method, was dispersed into nanosol by a controlled bead-mill wet process. The (+) charged Y2O3:Eu3+ nanosol was effectively coated on the (-) charged mica flake (MF) or the TiO2/mica flake (TMF) by an electrostatic interaction between the Y2O3:Eu3+ nanoparticles and MF or TMF at pH 6–8. The coating factors of Y2O3:Eu@MF were also studied and optimized by controlling the pH, stirring temperature, calcination temperature, and coating amount of Y2O3:Eu3+. The Y2O3:Eu3+ was partially coated and optimized on the MF or TMF surface with a coating coverage of about 40–50% or 60–70%, respectively. Y2O3:Eu@MF and Y2O3:Eu@TMF were exhibiting the luminescent property of a red color under a 254 nm wavelength, and had a color purity of over 95% according to CIE chromaticity coordinates. These materials were characterized by X-ray diffraction, FE-SEM, zeta potential, and a fluorescence spectrometer. These materials with luminescent and gloss properties prepared in this work potentially meet their applications for security purposes.