Silica Opal Research Articles

Radiation-Induced Paramagnetic Centers in Meso- and Macroporous Synthetic Opals from EPR and ENDOR Data

The paramagnetic defects and radiation-induced paramagnetic centers (PCs) in silica opals can play a crucial role in determining the magnetic and electronic behavior of materials and serve as local probes of their electronic structure. Systematic investigations of paramagnetic defects are essential for advancing both theoretical and practical aspects of material science. A series of silica opal samples with different geometrical parameters were synthesized and radiation-induced PCs were investigated by means of the conventional and pulsed X- and W-band electron paramagnetic resonance, and 1H/2H Mims electron-nuclear double resonance. Two groups of PCs were distinguished based on their spectroscopic parameters, electron relaxation characteristics, temperature and time stability, localization relative to the surface of silica spheres, and their origin. The obtained data demonstrate that stable radiation-induced E’ PCs can be used as sensitive probes for the hydrogen-containing fillers of the opal pores, for the development of compact radiation monitoring equipment, and for quantum technologies.

The Diversity of Archaeological Animal and Plant Remains Discovered at 18th–19th-Century Sites in Iași City (NE Romania)

Animal and plant remains recovered from two archaeological sites in Iași city (NE Romania) were analyzed in this work. The aim of this study was to contribute to the economic and environmental evaluation of an old urban settlement. The analyzed sites, both of value in archaeological preventive research, are dated to the 18th–19th centuries. The archaeozoological analysis consisted of anatomical, taxonomic, and taphonomic identifications, quantification, estimations of age at slaughter and sex, and osteometry. The results revealed that the animal remains are of domestic origin, as indicated by traces of butchering, and can be mainly described in terms of their frequencies (i.e., number of identified specimens and minimum number of individuals), selection for slaughter, morphology, and size. The results show that animal husbandry (e.g., cattle, sheep/goat, pig, and horse) had significant importance in the economy of the settlement, and cattle were preferred for consumption. Few remains were identified for wild mammals (i.e., red deer, wild boar, and hare), birds, and mollusks. The phytolith analysis indicated that some plant resources were used in the economy of this settlement. The identification of opal silica bodies revealed the presence of grasses and cultivated cereals.

Chemical activity score of siliceous rocks in development of self-cleaning cement material

The development of photocatalytically active cement materials characterized by a complex of positive properties, such as self-cleaning ability, decompose atmospheric air pollutants, eliminate unwanted odors, etc., is actual scientific direction in the field of building materials science. It is known that ‘core-shell’ compositions obtained by precipitation of photocatalyst particles on dispersed carriers (substrates) are one of the effective types of photocatalytic additives for cement systems. It should be noted that mineral raw materials of various genesis can act as a substrate. Foreign and domestic experience in obtaining ‘core-shell’ photocatalytic systems for cement materials shows that the type of photocatalytic agent carrier has a primary influence on the final parameters of the synthesized composite modifier. The purpose of this study was to establish patterns of influence of the composition of 3 types of opal-cristobalite rocks (diatomite, trepel, opoka) on their chemical activity. It was identified that the reactivity of siliceous rocks grows in the order of trepel → opoka → diatomite. Meanwhile, it was recorded that increase in the content of opal silica in the composition contributed to growth in the sedimentary rock reactivity. The obtained research results indicate the prospects of using diatomite and opoka as dispersed carriers of photocatalytic agents in the composition of self-cleaning cement concretes.

Geochemical processes and mechanisms for cesium enrichment in a hot-spring system

Abstract Geothermal systems in Tibet, a crucial geothermal region in China, belong to the Mediterranean-Himalayan geothermal belt and are characterized by a broad distribution of cesium (Cs) bearing geyserite deposits. Targejia, one of the largest Cs-bearing geyserites in southern-western Tibet, contains 1.446 × 104 tons of Cs. The highest ore grade reaches 2.89 wt%, and the ore-forming process can be subdivided into mineralization stages I to V. Cs is heterogeneously distributed in geyserites. Herein, two Cs-bearing ores are investigated, with distinct characteristics of (1) low-Cs-bearing ore (amorphous silica opal-A and opal-CT type) with low Cs (average of ~0.2 wt%), Na, K, Al, and Ca contents, and (2) high-Cs-bearing ore (clay type) with high-Cs (average of ~1.40 wt%), -Na, -K, -Al, and -Ca contents. It is reported for the first time that Cs primarily exists in clay rather than in amorphous silica opal. The Cs-enrichment mechanisms are different for the above two Cs-bearing geyserite types: (1) The deprotonated –OH, surrounded by water molecules, controls the amount of Cs absorbed on the geyserite surface (Si–OH) in the low-Cs-bearing ore. (2) The variable Cs content depends on the Al content because Al substitutes Si, yielding more negative charges to absorb Cs in the high-Cs-bearing ore. Geothermal fluid loading-mass elements, such as Cs and SiO2, precipitate as amorphous silica (opal) with clay minerals. Mineral saturation index modeling was used to predict the most applicable physical parameters for ore formation. The results confirm that the ore forms at ~85 °C and a pH of ~8.5 in the Na-Cl system at stage V. The degree of Cs enrichment reduces from the latest stage V (0–4 ka) to the early stage IV (4–17 ka), and is controlled by clay dissolution, which might further relate to the climate change in Tibet’s Holocene. Fluid-rock interaction modeling shows that dissolution–reprecipitation induces a higher order of amorphous silica formation and clay dissolution at >40 °C and pH of 5–9 at stages V and III, excluding Cs from the ore.

Characterization of Geochemistry in Hydrothermal Sediments From the Newly Discovered Onnuri Vent Field in the Middle Region of the Central Indian Ridge

The recently discovered Onnuri hydrothermal vent field (OVF) is a typical off-axis ultramafic-hosted vent system, located on the summit of the dome-like ocean core complex (OCC) at a distance of ∼12 km from the ridge axis along the middle region of the Central Indian Ridge (CIR). The plume chemistry with high methane anomaly was consistent with the precursor of hydrothermal activity; however, the fundamental characteristic of the OVF system, such as the hydrothermal circulation process and source of heat, remains poorly understood. Here, we focus on the geochemical features of surface sediments and minerals collected at and around the OVF region in order to better understand this venting system. The results reveal that the OVF sediments are typified by remarkably high concentrations of Fe, Si, Ba, Cu, and Zn, derived from hydrothermal fluid and S and Mg from seawater; depleted C-S isotope compositions; and abundant hydrothermally precipitated minerals (i.e., Fe–Mn hydroxides, sulfide and sulfate minerals, and opal silica). Notably, the occurrence of pure talc and barite bears witness to strong hydrothermal activity in the OVF, and their sulfur and strontium isotope geochemistry agree with extensive mixing of the unmodified seawater with high-temperature fluid derived from the gabbroic rock within the ultramafic-dominated ridge segment. The findings reveal that the OVF is a representative example of an off-axis, high-temperature hydrothermal circulation system, possibly driven by the exothermic serpentinization of exposed peridotites. Given the widespread distribution of OCC with detachment faults, furthermore, the OVF may be the most common type of hydrothermal activity in the CIR, although the paucity of data precludes generalizing this result. This study provides important information contributing to our understanding of the ultramafic-hosted hydrothermal vent system with a non-magmatic heat source along mid-ocean ridges.

A real-time temperature responsive material based on partial inverse opal photonic crystals and cholesteric liquid crystals

In this paper, we fabricated a temperature-sensitive material with a partial inverse opal structure, which can reversibly and quickly identify small temperature changes at room temperature and show significant color differences. First, we synthesized silica microsphere and prepared silica photonic crystals (PCs), then we composited PCs with polymer. After covering the mask, we prepared partial inverse opal silica PCs template by using selective etching. The temperature-sensitive liquid crystals (LCs) composed of cholesterol oleyl carbonate (COC), cholesterol nonanoate (CPE) and cholesterol benzoate (CBZ) were filled in partial inverse opal silica PCs template. In the end, we sealed the film by methyl methacrylate (MMA) and polyethylene glycol diacrylate (PEGDA). In this way, we prepared the fast temperature-sensitive dual-opal PCs/LCs composite film, and studied the mechanism of temperature regulation on material display mode. As the temperature gone from 26 °C to 30 °C, the material changed colors rapidly from red to blue. The result showed that this PCs/LCs composite film had well temperature response performance, which can monitor slight environmental temperature change. By selective etching the material, we designed PCs film patterns. The different patterning states displayed and changed fast at different temperatures, showing that the material had a good application prospect in the fields of temperature sensor, anti-counterfeiting, and display device.

A highly sensitive and reproducible multiplex mycotoxin SERS array based on AuNPs-loaded inverse opal silica photonic crystal microsphere

A highly sensitive and reproducible multiplex mycotoxin SERS array has been established based on gold nanoparticles (AuNPs)-loaded inverse opal silica photonic crystal microsphere (SIPCM). Three types of Raman nanotags were synthesized by covalently grafting different antibodies and non-covalently loading different organic dyes onto the AuNPs for coding corresponding mycotoxins. To enhance Raman signal, AuNPs were loaded on the surface of SIPCM to create hot-spots once the Raman nanotags came closely. The maximal electric field enhancing effect in SIPCM with AuNP dimer could reach to 8 times. The assay principle was based on the competition immunoassay between the mycotoxins in sample and the artificial antigens immobilized on the surface of SIPCM. The three Raman nanotags could be integrated into an array to qualitatively and quantitatively detect multiplex mycotoxins in a sample. Such SERS-based assay displayed wide linear detection ranges of 0.001–10 ng/mL for ochratoxin A (OTA), 0.001–10 ng/mL for fumonisin B1 (FB1), and 0.1–1000 ng/mL for deoxynivalenol (DON), and low limits of detection (LOD) of 2.46 pg/mL for OTA, 0.20 pg/mL for FB1, and 68.98 pg/mL for DON. The recovery rates of the new method were measured to be 77.68–104.69% for OTA, 76.39–117.73% for FB1, and 70.95–113.16% for DON, in agreement with that of the classical ELISA method. The SERS-based method shows obvious advantages over fluorescence label or enzyme catalytic chemiluminescence methods, having a great application potential in rapidly screening multiplex mycotoxins in real samples.

Micro Humidity Sensor Based on a GaN Chip With Silica Opal

The fabrication of a micro humidity sensor based on a GaN chip with silica opal is reported. The GaN chip containing InGaN/GaN multi-quantum well provides the two key functions of light emission and detection and the emitted light can be directly coupled into and out of the humidity-sensitive opal through the transparent sapphire substrate. The novel chip-scale integration scheme fully eliminates the complex assembly of external optical elements. The measured photocurrent signal quantitatively reflects the humidity change and has a linear relation of 0.24 μA/% over a wide humidity range of 10-90 %. The developed micro-sensor possesses the advantages of compact size, low cost, high repeatability, and ease of integration and operation, which paves the way for its widespread adoption in humidity sensing.

Omnidirectional, Broadband, and Polarization‐Independent Near‐Perfect Light Absorption from Surface Plasmonic Excitation of a Corrugated Au–SiO2–Au Structure Fabricated with a Self‐Assembled Silica Opal Template

A corrugated metal–insulator–metal (cMIM) structural design for omnidirectional, broadband, and polarization‐independent near‐perfect light absorption (NPA) is proposed and demonstrated. The optimal structure consists of a (6 nm Au layer)–(70 nm SiO2 layer)–(90 nm Au layer) MIM structure on top of a self‐assembled silica opal template, which consists of monodisperse SiO2 nanospheres with an average diameter of 295 nm. The optical measurement demonstrates greater than 95% absorption for this optimal cMIM structure with incident light with wavelengths between 400 and 800 nm, and the incident angle varies from normal incidence to 60° off normal for both TE and TM polarizations. For the figure of merit (FOM) of the device performance, the spectral averaged absorption at normal incidence is calculated. The optimal cMIM structure demonstrates an FOM of 99.2%. Numerical simulations with rigorous coupling wave analysis (RCWA) and the finite difference time domain (FDTD) method to simulate the interaction between the incident light and the cMIM structure is carried out. The results qualitatively reproduce the structural dependence of the absorption of cMIM structures. They further indicate that multiple modes of surface plasmon polariton (SPP) excitation at various wavelengths are responsible for the NPA of the cMIM structure.

Origin and implications of early diagenetic quartz in the Mississippian Bowland Shale Formation, Craven Basin, UK

Silica cementation exerts a key control on the compaction and geotechnical properties of mudstones, and by extension, the style of hydrocarbon and/or mineral systems present in a given sedimentary basin. Integrated microscopic and bulk geochemical observations demonstrate that siliceous mudstones in the Bowland Shale Formation, a target for UK shale gas extraction, exhibit abundant dispersed, discrete, μm-scale quartz cements, and exhibit silica enrichment (‘excess’) above a local detrital Si/Al threshold of 2.5. Dissolution of siliceous radiolarian tests during early diagenesis is identified as the main source of silica (opal A) required for quartz precipitation, either via opal CT or directly to quartz, and potentially generated as a product of anoxic marine ‘weathering’ (dissolution) of reactive silicates during early diagenesis. Excess silica correlates with free hydrocarbons (S1) normalised to total organic carbon (oil saturation index; OSI); we propose early diagenetic quartz precipitation suppressed pore collapse (‘buttress effect’), retaining the pore space capacity to host oil. Quartz precipitation was likely catalysed, for example via low porewater pH, elevated Al and/or Fe oxide content, and/or abundant labile organic matter. Juxtaposition of siliceous mudstones and mudstones lacking quartz cement indicates silica was immobile beyond the bed scale. Thus metre-scale siliceous packages likely represent more prospective units within the Bowland Shale (in terms of unconventional hydrocarbons), on the basis of early diagenetic biogenic-derived quartz cementation leading to improved hydrocarbon storage capacity coupled to enhanced brittleness. These findings are relevant for shale oil and shale gas systems, specifically where oil retained in pores subsequently cracks to generate gas. These findings also suggest the Bowland Shale is a sub-class of black shale, defined by the potential to host a relatively large volume of early diagenetic fluids, derived from anoxic bottom waters, which were potentially S- and/or metal-bearing. This is potentially relevant for understanding the genesis of adjacent and related Pb-Zn mineral deposits.

Phase and Mineralogical Transformations of Opal Clays in the Production of Ceramic Bricks

Due to a wide range of studies, it has been established that siliceous clays can be an alternative source of raw materials for the production of various types of structural ceramics. Their wide occurrence contributes to their usage in industrial production. Siliceous clays have a specific mineralogical composition and were previously considered only as an additive to increase the plasticity of the main raw material. The chemical composition, properties of green and fired siliceous clays of the Malchevsky deposit has been studied in detail. They consist of 67-70% silica, 13-15% alumina, and 1-3% alkaline earth oxides. The main minerals are opal silica and beidellite. These thermographs confirm the presence of montmorillonite, zeolites, mica and hydromica, opal silica and quartz. It is established that siliceous clays belong to the groups of medium dispersed and highly plastic raw materials. Despite the increased molding moisture and great shrinkage, they are moderately sensitive to drying and allow you to get molding masses with high binding property. At the firing temperature of 1000-1020 ° C, the brick is free from defects, the strength grade is M200-250, and the frost resistance is F75. There are X-ray data of siliceous clays burned at temperatures of 900, 950, 1000, 1050, 1100° C. Significant phase transformations become noticeable at a temperature of 1000° C, when the process of transition of amorphous opal silica to cristobalite begins. At 1050° C, the formation of a glass phase begins. The results obtained suggest that the main phases of the fired material based on siliceous clays are quartz and cristobalite with a low degree of structural perfection and the formation of the microstructure occurs in the interval 1000-1100° C. So, siliceous clays can be considered as the main and additional material for the production of various types of structural ceramics.

In situ encapsulation of Co/Co3O4 nanoparticles in nitrogen-doped hierarchically ordered porous carbon as high performance anode for lithium-ion batteries

This work explores the fabrication of Co/Co3O4 nanoparticles encapsulated in nitrogen-doped hierarchically ordered porous carbon (Co/Co3O4/NHPC) and investigates their electrochemical performance for lithium-ion batteries (LIBs). Co/Co3O4/NHPC is obtained from a typical dual-template (silica opal is employed as a hard template and F127 (EO106PO70EO106) acts as a soft template to guide the mesoporous structure) by taking advantage of resol (phenol/formaldehyde) as carbon source, dicyandiamide as nitrogen source, and cobalt nitrate as cobalt source. We have optimized the performance of Co/Co3O4/NHPC composite base on the contents of Co/Co3O4 in composite. 0.6-Co/Co3O4/NHPC (0.6 g cobalt nitrate in precursor solution) demonstrates a high discharge capacity (1823 mAh g−1 after 200 cycles at 0.2 A g−1), excellent cycling stability, and high-rate capability (1313/1056/576 mAh g−1 after 500 cycles at 2/5/10 A g−1). This outstanding LIB anode performance can be attributed to the hierarchically ordered porous carbon that could effectively provide rapid diffusion path way for electrolyte and metallic Co that could accelerate the transmission of electrons.

Formation of Hydrophilic and Hydrophobic Surfaces on Plastics by a Facile Method Using a Silica Opal

A facile method for forming both hydrophilic and hydrophobic surfaces is proposed here. Synthetic opal composed of mono-sized spheres of 250–290 nm was placed in contact with plastic substrates at ...

Removal of hexavalent chromium ion from aqueous solution using nanoscale zero-valent iron particles immobilized on porous silica support prepared by polymer template method

Porous silica supported nanoscale zero-valent iron was prepared by a polymer template method in order to effectively remove a hexavalent chromium ion (Cr(VI)) in an aqueous solution. It did not show a deterioration of Cr(VI) removal efficiency, which could be caused by the surface oxidation and agglomeration of nanoscale zero-valent iron (NZVI) particles. Porous silica by the polymer template method showed quite unique structure, which we named as quasi-inverse opal silica (QIOS), and it showed high surface area (375.4m2/g) and fine pore size (76.5 nm). NZVI immobilized on the surface of QIOS (NZVI@QIOS) was added to an aqueous Cr(VI) solution at 0.025 g/L, and it showed over 96% Cr(VI) removal efficiency. Such a high removal efficiency of Cr(VI) was maintained over two weeks after preparation (92% after 16 days). Morphology of porous silica supported nanoscale zero-valent iron was analyzed by TEM and FE-SEM. Identification of the reaction compounds produced by the reaction of Cr(VI) and zero-valent iron (Fe(0)) was made by the application of XPS.

Lunar and Martian Silica

Silica polymorphs, such as quartz, tridymite, cristobalite, coesite, stishovite, seifertite, baddeleyite-type SiO2, high-pressure silica glass, moganite, and opal, have been found in lunar and/or martian rocks by macro-microanalyses of the samples and remote-sensing observations on the celestial bodies. Because each silica polymorph is stable or metastable at different pressure and temperature conditions, its appearance is variable depending on the occurrence of the lunar and martian rocks. In other words, types of silica polymorphs provide valuable information on the igneous process (e.g., crystallization temperature and cooling rate), shock metamorphism (e.g., shock pressure and temperature), and hydrothermal fluid activity (e.g., pH and water content), implying their importance in planetary science. Therefore, this article focused on reviewing and summarizing the representative and important investigations of lunar and martian silica from the viewpoints of its discovery from lunar and martian materials, the formation processes, the implications for planetary science, and the future prospects in the field of “micro-mineralogy”.

What is Your “Phytolith Load”? An Examination of the Potential for Cross-Contamination During Phytolith Extraction

Phytoliths—amorphous opal silica bodies that form in living plant tissues—are assumed to be stable components of a soil matrix, minimally impacted by normal physical forces. This stability enables archaeologists to access an archive of prior vegetative landscapes when discrete horizons are recovered. However, there is a small chance of phytoliths moving in a laboratory setting via aeolian forces, especially after they have been isolated from other materials such as clay, organics, and carbonates, and when multiple samples are being processed simultaneously. As a result, an assessment of contamination risk on sample extraction is necessary for interpreting the results of phytolith analyses. We designed a study to test the potential for contamination on slides in two different locations of the phytolith laboratory. The results of our study inform how we can improve on phytolith processing protocols and analyses to reduce the potential effect of cross-contamination between samples.

Taxonomic assessment of opal phytoliths from grasses of deltaic West Bengal, India

In the present study, taxonomic potential of opal phytoliths was examined in grasses from lower Gangetic delta, West Bengal, India. The study revealed that finer classification of phytoliths can increase the efficacy of opal silica as taxonomic proxy by minimizing the influences of multiplicity and redundancy. We isolated 187 phytolith sub‐morphotypes, categorized under 10 major groups, from 110 grass species belonging to 45 genera, 21 sub‐tribes, 13 tribes and 7 subfamilies. Cluster and correspondence analyses showed that all the significantly represented subfamilies can be clearly distinguished on the basis of either principal morphotypes or sub‐morphotypes. However, genus/species level discrimination may only be possible by deploying phytolith based identification key developed by utilizing detailed grass phytolith micro‐morphometry and frequency attributes. We conclude that grass phytolith characteristics provide useful and significant information for distinguishing grass taxa of deltaic West Bengal.

Surface imprinted conducting polymer patterns electrochemically grown from gold pinhole arrays on 2D inverse silica opals and their effective use in aspartame detection

This paper introduces a novel method to electrochemically grow surface imprinted poly(3-TAA-co-EDOT) patterns from a gold pinhole array inside an inverse silica opal monolayer for the detection of aspartame. Using colloidal lithography, the designed 2D silica opal photonic crystal acts as an insulating porous mask with exposed gold pinhole arrays to form molecularly imprinted conducting polymers (MICPs). As the number of cyclic voltammetry (CV) cycles is increased, the MICPs grew toward the silica inner wall retaining the imprinted pillar array formed on the gold pinholes. For all three types of MICP films investigated (i.e., CV1, CV3, and CV5), artificial recognition sites were successfully generated after aspartame extraction; aspartame adsorption was then investigated using quartz crystal microbalance measurements. In the case of MICP-CV5, all of its sensing properties such as sensing response (Δf), imprinting effect (If), and selectivity were found to be superior to those measured for the other polymers (i.e., MICP-CV1 and −CV3). Furthermore, the MICP-CV5 film demonstrated significantly enhanced sensing behavior relative to 2D inverse porous MICP (p-MICP) films with similar surface morphologies, which were grown electrochemically by conventional polystyrene colloidal lithography. Overall, the results presented herein clearly demonstrate that this novel lithographical method leads to an increased number of imprinting sites in MICP structures, which impart the resultant polymers with enhanced sensing properties.

Authigenic siliceous-carbonate concretions in Cenomanian–Turonian carbonates of southern Croatia; geochemical and biotic record

Numerous regular and irregularly shaped concretions were discovered in southern Croatia within the Upper Cretaceous carbonate deposits, which consist mostly of bioclastic wackestones and packstones. The size of the concretions varies from 2 to 25 cm in diameter for the regular, and up to 40 cm in length for the irregular ones. The concretions have different internal structures and compositions, which vary from those of the host rocks. Some concretions are entirely siliceous, while others exhibit alternating opal silica and carbonate-rich zones. Silica is derived from opal-A secreting marine biota, mostly sponges, whose spicules can be found within the concretions and in the surrounding limestones. The regular shape and alterations of zones are the result of the diffusive supply and fast “consummation” of silica at the growth site. Determined fossil community and bitumen found in the surrounding limestones indicate deposition in the oxygen-depleted deep-marine environment of the Adriatic Carbonate Platform, which belongs to the Sveti Duh Formation (latest Cenomanian–Early Turonian). The carbon isotope composition of the concretions corresponds to the globally known Cenomanian–Turonian ‘Oceanic Anoxic Event’ (OAE 2).

Fabrication and simulation of inverse poly(ferrocenylmethylvinylsilane)/silica opal structures and their optical properties

Photonic crystal structures were fabricated by the formation of periodic arrays of poly(ferrocenylsilane) (PFS) derivations and silica spheres. Here, we present the primary steps of a simulation-driven design of photonic crystal based on PFS as a potentially stimuli-responsive polymer, which can present predesigned color when subjected to the visible light. The poly(ferrocenylmethylvinylsilane) (PFMVS) was synthesized by photolytic anionic ring opening polymerization of methylvinylsila[1]ferrocenophane monomer under controlled condition and monodisperse silica spheres were synthesized by the Stober process. Bare silica opal was prepared by the convective self-assembly process of different sizes of silica spheres on glass substrate followed by infiltration of PFMVS to obtain PFMVS/silica opal and finally removal of the silica spheres by acid washing to attain the inverse PFMVS opal. The particle size of silica spheres along with the refractive indices contrast of different components forming photonic crystal played an important role in obtaining the maximum reflectance wavelength of the desired opal. Photonic crystal prepared by 210, 270, and 330 nm monodisperse silica spheres represents the blue, green, and red color, respectively. Simulation analyses of these opal structures were investigated by using the plane-wave expansion (PWE) method to assess the photonic crystal behavior versus the visible light. According to the simulation results, the photonic crystal structure was designed. The experimental reflectance outcomes of the three opal structures were in good agreement with the simulation analysis.