In situ electron beam irradiated rapid growth of bismuth nanoparticles in bismuth-based glass dielectrics at room temperature

In this study, in situ control growth of bismuth nanoparticles (Bi(0) NPs) was demonstrated in bismuth-based glass dielectrics under an electron beam (EB) irradiation at room temperature. The effects of EB irradiation were investigated in situ using transmission electron microscopy (TEM), selected-area electron diffraction and high-resolution transmission electron microscopy. The EB irradiation for 2-8 min enhanced the construction of bismuth nanoparticles with a rhombohedral structure and diameter of 4-9 nm. The average particle size was found to increase with the irradiation time. Bismuth metal has a melting point of 271 A degrees C and this low melting temperature makes easy the progress of energy induced structural changes during in situ TEM observations. This is a very useful technique in nano-patterning for integrated optics and other applications

Single-Step Synthesis and Surface Plasmons of Bismuth-Coated Spherical to Hexagonal Silver Nanoparticles in Dichroic Ag:Bismuth Glass Nanocomposites

Here, we report for the first time the synthesis of bismuth-coated silver nanoparticles in dichroic bismuth glass nanocomposites by a novel and simple one-step melt quench technique without using any external reducing agent. The metallic silver nanoparticles (Ag NPs) were generated first, and subsequently, metallic bismuth was deposited on the Ag NPs and formed a thick layer. The reduction of Bi(3+) to Bi(o) and subsequently its deposition on the Ag NPs (which were formed earlier than Bi(o)) in the K(2)O-Bi(2)O(3)-B(2)O(3) (KBB) glass system have been explained by their standard reduction potentials. The UV-vis absorption spectra show a prominent surface plasmon resonance (SPR) absorption band at 575 nm at lower concentrations (up to 0.01 wt%); three bands at 569, 624 and 780 nm at medium concentration (0.02-0.03 wt%); and two weak bands at 619 and 817 nm at highest concentration (0.06 wt%) of silver. They have been explained by the electrodynamics theories. TEM images reveal the conversion of spheroidal (5-15 nm) to hexagonal (10-35 nm) shaped Ag NPs with the increase in concentration of silver (up to 0.06 wt%). SAED pattern confirms the crystalline planes of rhombohedral bismuth and cubic silver. Thermal treatment at 360 A degrees C, which is the glass transformation temperature (T (g)) of the sample containing lower concentration of silver (0.007 wt%), shows red-shifted SPR band due to increase in size of NPs. Whereas the sample containing higher concentration (0.06 wt%) of silver under similar treatment exhibited changes in SPR spectral profile happened due to conversion to spherical NPs from hexagonal shape and reduction in size (10-20 nm) of NPs after heat treatment for 65 h. HRTEM images corroborate the different orientations of the NPs. FESEM images reveal hexagonal disk like structure having different orientations. Dichroic nature of the nanocomposites has been explained with the size and shape of Ag nanoparticles. We believe that this work will create new avenues in the area of nanometal-glass hybrid nanocomposites and the materials have significant applications in the field of optoelectronics and nanophotonics

Photoluminescence enhancement of Eu(3+) by energy transfer from Bi(2+) to Eu(3+) in bismuth glass nanocomposites

Bi(2+)-enhanced photoluminescence of Eu(3+) doped Bi(0)-bismuth glass nanocomposites are demonstrated here. The generation of bismuth nanoparticles (NPs) and its typical surface plasmon resonance at 460 nm are controlled by the oxidative method instead of the conventional reduction technique during melt-quench processing. TEM images evidence the presence of spherical Bi(0) NPs of 10-15 nm sizes and SAED pattern reveals their crystalline rhombohedral phase formation. The enhanced photoluminescence of Eu(3+) is found to occur at 613 and 703 nm due to (5)D(0 ->)(7)F(2) and (5)D(0)->(7)F(4) transitions respectively. We believe that it has happened due to energy transfer from Bi(2+) to Eu(3+)

Controlled oxidative synthesis of Bi nanoparticles and emission centers in bismuth glass nanocomposites for photonic application

Here we demonstrate an oxidative process to control metallic bismuth (Bi(0)) nanoparticles (NPs) creation in bismuth glass nanocomposites by using K(2)S(2)O(8) as oxidant and enhanced transparency of bismuth glasses. Formation of Bi(0) NPs has been monitored by their distinct surface plasmon resonance (SPR) band at 460 nm in the UV-visible absorption spectra. It is further confirmed by the transmission electron microscopy (TEM) images which disclose the formation of spherical Bi(0) NPs whereas the selected area electron diffraction (SAED) pattern reveals their crystalline rhombohedral phase. These glasses are found to exhibit visible and near infrared (NIR) luminescence bands at 630 and 843 nm respectively on excitation at 460 nm of the SPR band. It is realized that the luminescence center of bismuth species is an uncertain issue, however, it is reasonable to consider that the emission band at 630 nm is due to the combination of (2)D(5/2) -> (4)S(3/2) of Bi(0) and (2)P(3/2) (1) -> (2)P(1/2) of Bi(2+) transitions, and that of NIR emission band at 843 nm is attributed to the (2)D(3/2) -> (4)S(3/2) of Bi(0) transition. (C) 2011 Elsevier B.V. All rights reserved

Effects of TiO(2)-SiO(2) fillers on thermal and dielectric properties of bismuth glass microcomposite dielectrics for plasma display panel

The combined effects of TiO(2) and SiO(2) fillers on thermal and dielectric properties of new lead-free environmental friendly zinc bismuth borate, ZnO-Bi(2)O(3)-B(2)O(3) (ZBIB) glass microcomposite dielectrics have been investigated from the viewpoint of application as rear glass dielectric layer of plasma display panels (PDPs). The interaction of fillers with glass occurred during firing has also been explored by XRD, SEM and FTIR spectroscopic analyses. All the properties are found to be regulated by the covalent character (a fundamental property) of resultant microcomposite dielectrics. In this work, the co-addition of TiO(2)-SiO(2) filler to ZBIB glass is found to be more effective to adjust the required properties to employ with PD200 glass substrate in PDP technology

The State-of-the-Art in Air Pollution Monitoring and Forecasting Systems using IoT, Big Data, and Machine Learning

The quality of air is closely linked with the life quality of humans, plantations, and wildlife. It needs to be monitored and preserved continuously. Transportations, industries, construction sites, generators, fireworks, and waste burning have a major percentage in degrading the air quality. These sources are required to be used in a safe and controlled manner. Using traditional laboratory analysis or installing bulk and expensive models every few miles is no longer efficient. Smart devices are needed for collecting and analyzing air data. The quality of air depends on various factors, including location, traffic, and time. Recent researches are using machine learning algorithms, big data technologies, and the Internet of Things to propose a stable and efficient model for the stated purpose. This review paper focuses on studying and compiling recent research in this field and emphasizes the Data sources, Monitoring, and Forecasting models. The main objective of this paper is to provide the astuteness of the researches happening to improve the various aspects of air polluting models. Further, it casts light on the various research issues and challenges also.Comment: 30 pages, 11 figures, Wireless Personal Communications. Wireless Pers Commun (2023

Bismuth Oxide and Bismuth Oxide Doped Glasses For Optical and Photonic Applications

Glasses formed with heavy metal (atomic weight >100) oxides (HMO) have received significant attention because of their interesting physical and optical properties. In this perspective, bismuth (atomic weight = 209) oxide containing glasses is one of the most important members of this family. Bismuth oxide glasses are very useful for exploiting as lead-free, low-softening point, high refractive index, high density and radio shielding glasses. These glasses have long infrared cut-off, which makes them ideal candidates for optical transmission in the infrared to visible region. Thus there has been an increasing interest in the studies of synthesis, microstructure, physical and optical properties of bismuth oxide containing glasses and bismuth oxide doped glasses. Optical absorption studies of bismuth oxide glasses yield important information regarding their electronic states. The synthesis of size-controlled, spherical Bi nanoparticles and strategies for generation of various shaped Bi nanoparticles in glass matrix is again a very attractive area for nanomaterial research. Moreover, the generation of surface plasmon resonance due to various shape and sizes bismuth nanoparticles is yet again open a very fascinating research area for plasmonic, nanophotonic and optoelectronic applications. Recent advances have sparked intense interest in bismuthdoped optical materials. Their broadband photoluminescence near infrared (NIR) has been established in many glasses. The bismuth oxide doped fibre lasers and amplifiers have created up to now to cover the spectral region 1100 to 1550 nm. The current trends show that the bismuth oxide and its doped glasses are very attractive and important optical materials for various scientific as well as technological applications

Oxidative control of surface plasmon resonance of bismuth nanometal in bismuth glass nanocomposites

We demonstrate here a novel oxidative process to control the metallic bismuth (Bi degrees) nanoparticles (NPs) formation in bismuth glass nanocomposites by using KClO(4) and KNO(3) as oxidant instead of usual reducing technique. The formation of Bi degrees NPs has been monitored by its distinctive surface plasmon resonance (SPR) band at 460 nm in the UV-vis absorption spectra. It is further confirmed by the TEM images of Bi degrees NPs using KNO(3) and KClO(4) which show the formation of spherical Bi degrees NPs of 2-15 nm sizes and the SAED pattern reveals their crystalline rhombohedral phase. Using this technique it is possible to control the SPR band of nanobismuth (Bi degrees) in bismuth glasses. (C) 2009 Elsevier B.V. All rights reserved

Mechanochemical Synthesis of Nano Calcium Silicate Particles at Room Temperature

Nano-sized calcium silicate powders were synthesized at room temperature by the new mechanochemical method using a high energy planetary ball mill. The formation of calcium silicate from its raw materials (calcium carbonate and de-hydrated silica gel) was monitored by the XRD analysis with progression of ball milling. It is observed that the synthet-ic process comes to an end through the following three sequential stages: comminution of raw materials, recombination of comminuted raw materials to final product, and comminution of final product to smaller sizes. The nanostructure of the synthesized powder was realized by the FESEM photomicrograph, TEM image and XRD analyses. These analytical observations have revealed that the nano-sized polycrystalline calcium silicate particles are formed after about 6 h of ball milling and they are spheroidal in shape. The average particle size of the as-generated calcium silicate nanocrys-talline powders is found to be around 21 nm which decreases with increasing ball milling but increases with annealing at elevated temperature

Synthesis and characterization of low softening point high Bi(2)O(3) glasses in the K(2)O-B(2)O(3)-Bi(2)O(3) system

Synthesis of a new series of lead free low softening point (<470 degrees C) high Bi(2)O(3) (40-90 mol%) glasses in the K(2)O-B(2)O(3)-Bi(2)O(3) system by the melt-quench technique has been demonstrated here. Their structural, optical, thermal, electrical and other physical properties have been evaluated by X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), FT-infrared reflection (FTIRR) spectroscopy, UV-Visible spectroscopy, dilatometer, LCR meter, etc. techniques. The glass softening point, glass transition temperature and glass deformation temperature are found to vary in the ranges 410-465 degrees C, 354-409 degrees C and 376-427 degrees C respectively which are found to correlate well with the boron anomaly phenomenon (as revealed by FTIRRS) with gradual addition of Bi(2)O(3) in the glass matrix. The coefficient of thermal expansion shows a decreasing trend from 153 down to 109 x 10(-7) K(-1) whereas the dielectric constant increases from 21 to 34 with the increase in Bi(2)O(3) content. The theoretical optical basicity is found to increase from 0.93 to 1.15 while the optical band gap decreases from 2.86 down to 2.30 eV with the addition of Bi(2)O(3). The formation of metallic bismuth in these glasses during melting in air has been confirmed by the XRD, TEM, selected area electron diffraction (SAED) and high resolution TEM (HRTEM) analyses. The formation of a Bi(2)O(3) rich secondary phase in the glasses and their particle size distribution have been examined by the FESEM photomicrograph analysis. (C) 2011 Elsevier Inc. All rights reserved