Wide gamut, angle-insensitive structural colors based on deep-subwavelength bilayer media

AbstractWide gamut and angle-insensitive structural colors are highly desirable for many applications. Herein, a new type of lithography-free, planar bilayer nanostructures for generating structural colors is presented, which is basically composed of a deep-subwavelength, highly absorbing dielectric layer on an opaque metallic substrate. Experimental results show that a galaxy of brilliant structural colors can be generated by our structures, and which can cover ∼50% of the standard red–green–blue color space by adjusting the nanostructure dimensions. The color appearances are robust with respect to the angle of vision. Theoretical partial reflected wave analyses reveal that the structural color effect is attributed to the strong optical asymmetric Fabry–Perot-type (F–P-type) thin-film resonance interference. The versatility of the structural color properties as well as the simplicity of their fabrication processes make this bilayer structures very promising for various applications, such as security marking, information encryption, and color display, etc.

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Carbon Nanotube Gas Sensor Fabricated on Anodic Aluminum Oxide

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.124-126.1309 ◽

2007 ◽

Vol 124-126 ◽

pp. 1309-1312

Author(s):

Nguyen Duc Hoa ◽

Nguyen Van Quy ◽

Gyu Seok Choi ◽

You Suk Cho ◽

Se Young Jeong ◽

...

Keyword(s):

Carbon Nanotubes ◽

Carbon Nanotube ◽

Gas Sensor ◽

Chemical Vapor ◽

Fast Response ◽

Device Fabrication ◽

Alumina Oxide ◽

Response And Recovery ◽

New Type ◽

P Type

A new type of gas sensor was realized by directly depositing carbon nanotube on nano channels of the anodic alumina oxide (AAO) fabricated on p-type silicon substrate. The carbon nanotubes were synthesized by thermal chemical vapor deposition at a very high temperature of 1200 oC to improve the crystallinity. The device fabrication process was also developed. The contact of carbon nanotubes and p-type Si substrate showed a Schottky behavior, and the Schottky barrier height increased with exposure to gases while the overall conductivity decreased. The sensors showed fast response and recovery to ammonia gas upon the filling (400 mTorr) and evacuation.

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On expansion waves generated by the refraction of a plane shock at a gas interface

Journal of Fluid Mechanics ◽

10.1017/s0022112067001491 ◽

1967 ◽

Vol 30 (2) ◽

pp. 385-402 ◽

Cited By ~ 6

Author(s):

L. F. Henderson

Keyword(s):

Expansion Wave ◽

Plane Shock ◽

Wave System ◽

Expansion Waves ◽

Reflected Wave ◽

Expansion Fan ◽

New Type ◽

Self Similar ◽

Fixed Boundaries ◽

Mapping Theory

The paper deals with the regular refraction of a plane shock at a gas interface for the particular case where the reflected wave is an expansion fan. Numerical results are presented for the air–CH4 and air–CO2 gas combinations which are respectively examples of ‘slow–fast’ and ‘fast–slow’ refractions. It is found that a previously unreported condition exists in which the reflected wave solutions may be multi-valued. The hodograph mapping theory predicts a new type of regular–irregular transition for a refraction in this condition. The continuous expansion wave type of irregular refraction is also examined. The existence of this wave system is found to depend on the flow being self-similar. By contrast the expansion wave becomes centred when the flow becomes steady. Transitions within the ordered set of regular solutions are examined and it is shown that they may be either continuous or discontinuous. The continuous types appear to be associated with fixed boundaries and the discontinuous types with movable boundaries. Finally, a number of almost linear relations between the wave strengths are noted.

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A new type of local defects in very thin silicon dioxide films on arsenic-implanted p-type silicon

Proceedings of 5th International Symposium on the Physical and Failure Analysis of Integrated Circuits ◽

10.1109/ipfa.1995.487611 ◽

2002 ◽

Author(s):

W.S. Lau ◽

K.S. Pey ◽

W.T. Ng ◽

V. Sane ◽

J.M.C. Heng ◽

...

Keyword(s):

Silicon Dioxide ◽

Type Silicon ◽

Silicon Dioxide Films ◽

New Type ◽

Thin Silicon ◽

Local Defects ◽

P Type

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A Bi7.38Cr0.62O12+x crystal as a novel visible-light-active photocatalyst up to ∼650 nm

RSC Advances ◽

10.1039/c7ra03058d ◽

2017 ◽

Vol 7 (46) ◽

pp. 28797-28801 ◽

Cited By ~ 2

Author(s):

W. X. Liao ◽

X. L. Zhao ◽

T. S. Wang

Keyword(s):

Photocatalytic Activity ◽

Visible Light ◽

Photoelectric Response ◽

Excellent Photocatalytic Activity ◽

Visible Light Active ◽

Type Semiconductor ◽

New Type ◽

P Type

A new type of Bi-based p-type semiconductor, Bi7.38Cr0.62O12+x, has a strong photoelectric response until 647.4 nm and an excellent photocatalytic activity for decomposition and O2 production.

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Stomatocyte structural color-barcode micromotors for multiplex assays

National Science Review ◽

10.1093/nsr/nwz185 ◽

2019 ◽

Vol 7 (3) ◽

pp. 644-651 ◽

Cited By ~ 5

Author(s):

Lijun Cai ◽

Huan Wang ◽

Yunru Yu ◽

Feika Bian ◽

Yu Wang ◽

...

Keyword(s):

Biomedical Applications ◽

Colloidal Crystal ◽

Structural Color ◽

Multiplex Detection ◽

Color Coding ◽

Functional Elements ◽

Structural Colors ◽

Multiplex Assays ◽

Magnetic Elements ◽

Extracting Solvent

Abstract Artificial micromotors have a demonstrated value in the biomedical area. Attempts to develop this technology tend to impart micromotors with novel functions to improve the values. Herein, we present novel structural color-barcode micromotors for the multiplex assays. We found that, by rapidly extracting solvent and assembling monodispersed nanoparticles in droplets, it could form stomatocyte colloidal crystal clusters, which not only showed striking structural colors and characteristic reflection peaks due to their ordered nanoparticles arrangement, but also provided effective cavities for the integration of functional elements. Thus, the micromotors with catalysts or magnetic elements in their cavities, as well as with the corresponding structural color coding, could be achieved by using the platinum and ferric oxide dispersed pre-gel to fill and duplicate the stomatocyte colloidal crystal clusters. We have demonstrated that the self-movement of these structural color-barcode micromotors could efficiently accelerate the mixing speed of the detection sample and greatly increase the probe–target interactions towards faster and more sensitive single or multiplex detection, and the magnetism of these barcode micromotors enables the flexible collection of the micromotors, which could facilitate the detection processes. These features make the stomatocyte structural color-barcode micromotors ideal for biomedical applications.

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Developing an Automatic Color Determination Procedure for the Quality Assessment of Mangos (Mangifera indica) Using a CCD Camera and Color Standards

Foods ◽

10.3390/foods9111709 ◽

2020 ◽

Vol 9 (11) ◽

pp. 1709

Author(s):

Khanitta Ratprakhon ◽

Werner Neubauer ◽

Katharina Riehn ◽

Jan Fritsche ◽

Sascha Rohn

Keyword(s):

Vision System ◽

Mangifera Indica ◽

Color Space ◽

Evaluation Process ◽

Ccd Camera ◽

Optimal Level ◽

Blue Color ◽

Color Code ◽

Color Determination

Color is one of the key sensory characteristics in the evaluation of the quality of mangos (Mangifera indica) especially with regard to determining the optimal level of ripeness. However, an objective color determination of entire fruits can be a challenging task. Conventional evaluation methods such as colorimetric or spectrophotometric procedures are primarily limited to a homogenous distribution of the color. Accordingly, a direct assessment of the mango quality with regard to color requires more pronounced color determination procedures. In this study, the color of the peel and the pulp of the mango cultivars “Nam Dokmai”, “Mahachanok”, and “Kent” was evaluated and categorized into various levels of ripeness using a charge-coupled device (CCD) camera in combination with a computer vision system and color standards. The color evaluation process is based on a transformation of the RGB (red, green, and blue) color space values into the HSI (hue, saturation, and intensity) color system and the Natural Color Standard (NCS). The results showed that for pulp color codes, 0560-Y20R and 0560-Y40R can be used as appropriate indicators for the ripeness of the cultivars “Nam Dokmai” and “Mahachanok”. The peels of these two mango cultivars present two distinct colors (1050-Y40R and 1060-Y40R), which can be used to determine the fruit maturity during the post-ripening process. However, in the case of the cultivar “Kent”, peel color detection was not an applicable approach for determining ripeness; thus, the determination of the pulp color with the color code 0550-Y20R gave promising results.

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Anisotropic structural color particles from colloidal phase separation

Science Advances ◽

10.1126/sciadv.aay1438 ◽

2020 ◽

Vol 6 (2) ◽

pp. eaay1438 ◽

Cited By ~ 21

Author(s):

Huan Wang ◽

Yuxiao Liu ◽

Zhuoyue Chen ◽

Lingyu Sun ◽

Yuanjin Zhao

Keyword(s):

Colloidal Crystal ◽

Structural Color ◽

Inverse Opal ◽

Phase Separations ◽

Structural Colors ◽

Structure Morphology ◽

Dynamic Cell ◽

Cell Monitoring ◽

Colloid Nanoparticles ◽

Component Phase

Structural color materials have been studied for decades because of their fascinating properties. Effects in this area are the trend to develop functional structural color materials with new components, structures, or morphologies for different applications. In this study, we found that the coassembled graphene oxide (GO) and colloid nanoparticles in droplets could form component phase separations, and thus, previously unknown anisotropic structural color particles (SCPs) with hemispherical colloidal crystal cluster and oblate GO component could be achieved. The anisotropic SCPs, as well as their inverse opal hydrogel derivatives, were endowed with brilliant structural colors and controllable capabilities of fixation, location, orientation, and even responsiveness due to their specific structure, morphology, and components. We have also demonstrated that the anisotropic hydrogel SCPs with these features were ideal candidates for dynamic cell monitoring and sensing. These properties indicate that the anisotropic SCPs and their derivatives have huge potential values in biomedical areas.

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Direction-Independent Band Gaps Extension Based on Thue-Morse Photonic Heterostructures Containing Negative-Index Materials

Materials Science Forum ◽

10.4028/www.scientific.net/msf.675-677.1077 ◽

2011 ◽

Vol 675-677 ◽

pp. 1077-1080 ◽

Cited By ~ 1

Author(s):

Ou Yang Hong ◽

Xin Hua Deng

Keyword(s):

Optical Fibers ◽

Transverse Electric ◽

Negative Index ◽

Reflection Band ◽

Negative Index Materials ◽

One Dimensional ◽

Fabry Perot ◽

Potential Applications ◽

New Type ◽

Positive Index

The band structure and photonic spectrum of one dimensional Thue-Morse quasicrystal composed by negative-index materials and positive-index materials are studied. We show that a new type of the omnidirectional reflection band (ORB) exists in Thue-Morse photonic heterostructures. Compared to a single Thue-Morse quasicrystal, the frequency range of the ORB in a Thue-Morse photonic heterostructure can be notably enlarged, and the width and location of the ORB do not change with Thue-Morse order. The lower edge of the ORB depends only on transverse electric (TE) polarization, while the higher edge of the ORB depends only on transversemagnetic (TM) polarization. These results imply potential applications in improving planar microcavities, optical fibers, and Fabry–Perot resonators, etc.

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More Colorful than Ever!

Microscopy Today ◽

10.1017/s1551929512001022 ◽

2012 ◽

Vol 21 (1) ◽

pp. 8-9

Author(s):

Stephen W. Carmichael

Keyword(s):

Mate Choice ◽

Energy Cost ◽

Biological Material ◽

Nutritional Value ◽

Food Source ◽

Visible Spectrum ◽

Structural Color ◽

Blue Color ◽

Equatorial Africa ◽

Anatomical Arrangement

In nature, color can be imparted to a feature either by a pigment or a structure that selectively reflects a part of the visible spectrum. The latter is called structural color, and it may be brighter than a pigment. Structural color is often used by animals for signaling, mimicry, and/or mate choice. In plants, mainly fruits, structural color is probably used for mimicry. Silvia Vignolini, Paula Rudall, Alice Rowland, Alison Reed, Edwidge Moyroud, Robert Faden, Jeremy Baumberg, Beverley Glover, and Ullrich Steiner described the anatomical arrangement within the outer layers (epicarp) of a blue fruit found in equatorial Africa that results in a blue color more intense than that of any previously described biological material! Although this fruit (Figure 1) has no nutritional value, by imitating the appearance of a fresh nutritious fruit, it avoids the energy cost of producing pulp yet can be dispersed by birds. And not only can it imitate a food source, it is probably also dispersed by birds who use it to decorate their nests in order to attract mates.

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