Properties Of Bismuth Research Articles

Nonlinear optical studies of Bismuth-doped Titanium di-oxide colloids achieved by femtosecond Z-Scan technique

In this paper, we explored the nonlinear optical (NLO) properties of Bismuth (Bi) doped titanium dioxide (TiO2) nanoparticle (NP) colloids in ethanol, with laser pulses of duration ∼ 150 femtoseconds (fs). The Bi-doped TiO2 NPs were synthesized via the chemical route, sol-gel method. The increased photo response of TiO2 upon doping it with metals has become a burning issue to extend the applications of metal-doped TiO2 NPs as integral parts in solar cells, catalysts, phototherapy, etc. The bandgap of anatase TiO2 NPs was observed to be reduced to 2.89 eV upon doping Bi. The modified band structure of the Bi-doped TiO2 NPs demonstrates novel chemical, mechanical, and optical properties. NLO studies were conducted on Bismuth-doped TiO2 NPs submerged in ethanol employing femtosecond laser input pulses with incoming wavelengths 700, 750, 800, 850, 900, and 950 nm. It has been detected that open aperture (OA) studies performed at an input peak intensity of 100 MW/cm2 on Bi-doped TiO2 NPs in ethanol were exhibiting complex NLO behavior, i.e., reverse saturable absorption (RSA) in saturable absorption (SA) and SA in RSA with mostly effective two-photon absorption (1 + 1) coefficients. Particularly, at ∼800 nm, the behavior observed was so complex, i.e., RSA in SA in RSA in SA, with an effective 3 PA (2 + 1) co-efficient (γ) ∼6.5 × 10−24 m3/W2. The closed aperture (CA) studies at ∼37 MW/cm2 exhibited self-defocusing effects, i.e., an intensity-dependent refractive index (n2) with a negative signature.

First-Principle Prediction of a Ground State Crystal Properties of a One-dimensional Nanotube-like Structure on Bismuth

First-principle calculations and density functional theory (DFT) have been combined to comparatively investigate the band structure, phonon spectrum, and optical and elastic properties of one-dimensional nanotube-like Bi. Our calculation reveals that Bi exhibits metallic properties, based on the valence band top (VBT) that lies above the conduction band bottom (CBB), and this is known as a negative bandgap. The optical bandgap is found to be very small, with a value of 257[Formula: see text]meV. The absorption coefficient is observed to be very high, up to [Formula: see text][Formula: see text]cm[Formula: see text]. This quantity falls within the vacuum ultraviolet (VUV) region. According to our reflectivity data, up to 82% of light has been reflected, which could be suitable for optical coating. Our elastic calculations further suggest the Bi-material should be brittle and covalent. Our data provide a deep understanding of various properties of Bismuth and could be useful to other theoretical and experimentalists.

Effects of Bismuth Oxide Nanoparticles, Cisplatin and Baicalein-rich Fraction on ROS Generation in Proton Beam irradiated Human Colon Carcinoma Cells

Abstract Introduction: Proton beam radiotherapy is an advanced cancer treatment technique, which would reduce the effects of radiation on the surrounding healthy cells. The usage of radiosensitizers in this technique might further elevate the radiation dose towards the cancer cells. Material and methods: The present study investigated the production of intracellular reactive oxygen species (ROS) due to the presence of individual radiosensitizers, such as bismuth oxide nanoparticles (BiONPs), cisplatin (Cis) or baicalein-rich fraction (BRF) from Oroxylum indicum plant, as well as their combinations, such as BiONPs-Cis (BC), BiONPs-BRF (BB), or BiONPs-Cis-BRF (BCB), on HCT-116 colon cancer cells under proton beam radiotherapy. Results: It was found that the ROS in the presence of Cis at 3 Gy of radiation dose was the highest, followed by BC, BiONPs, BB, BRF, and BCB treatments. The properties of bismuth as a radical scavenger, as well as the BRF as a natural compound, might contribute to the lower intracellular ROS induction. The ROS in the presence of Cis and BC combination were also time-dependent and radiation dose-dependent. Conclusions: As the prospective alternatives to the Cis, the BC combination and individual BiONPs showed the capacities to be developed as radiosensitizers for proton beam therapy.

Galvanomagnetic Properties of Bismuth–Antimony Films under Conditions of Plane Tensile Strain

Galvanomagnetic Properties of Bismuth–Antimony Films under Conditions of Plane Tensile Strain

Thermomagnetic Correlation in La0.85-xBixNa0.15MnO3 Soft Ferromagnet due to Nonmagnetic Bi3+ Substitution

We report the structural, magnetic, and magnetocaloric properties of Bismuth (Bi)-substituted manganite La0.85-xBixNa0.15MnO3 (x=0, 0.1, 0.2, 0.25, and 0.3). X-ray diffraction data implicates the rhombohedral structure with Roverline{3}c space group. Bi2O3 has helped in ensuring phase pure, densified compounds even at low sintering temperature and hence avoiding the evaporation of volatile sodium. The increase in grain size and decrease in magnetic transition temperature (TC) are due to the Bi chemical activity and electronic structure. The samples have shown indirect magnetic transformation from soft ferromagnet to canted ferromagnet/antiferromagnet with Bi. Griffiths phase-like behavior in the inverse magnetic susceptibility was observed for x=0.1; with further increase in Bi, the samples are found to develop the antiferromagnetic competing phase. The phenomenological model was used to model the thermomagnetic behavior of all the samples. The sample with x=0.1 shows an increase in magnetic entropy change upon Bi substitution and the maximum of magnetic entropy change is seen at 275K emphasizing its potential in room temperature magnetic refrigeration.

Is There a Role for Bismuth in Diarrhea Management?

Diarrhea, an illness of both the developed and developing world, involves the burdensome characteristics of frequent bowel movements, loose stools, and abdominal discomfort. Diarrhea is a long-standing challenge in palliative care and can have a myriad of causes, making symptomatic treatment pertinent when illness evaluation is ongoing, when there is no definitive treatment approach, or when effective treatment cannot be attained. Symptomatic therapy is a common approach in palliative care settings. Bismuth is a suitable agent for symptomatic therapy and can be effectively employed for management of chronic diarrhea. The objective of this narrative review is to examine the role of bismuth in management of diarrheal symptoms. To explore this, PubMed (including Medline) and Embase were used to search the existing literature on bismuth and diarrhea published from 1980 to 2019. It was found that bismuth has potential utility for diarrheal relief in multiple settings, including microscopic colitis, traveler’s diarrhea, gastrointestinal infection, cancer, and chemotherapy. It also has great potential for use in palliative care patients, due to its minimal side effects. Overall, the antisecretory, anti-inflammatory, and antibacterial properties of bismuth make it a suitable therapy for symptomatic treatment of diarrhea. The limited range of adverse side effects makes it an appealing option for patients with numerous comorbidities. Healthcare providers can explore bismuth as an adjunct therapy for diarrhea management in an array of conditions, especially in the palliative care setting.

Thin-film heat-sensitive elements on the basis of semimetals for electromagnetic radiation receivers

The paper presents the generalized results of the authors’ work on the study of thin films of semimetals, which can be used in the development of universal electromagnetic radiation receivers. It is shown that thin-film materials based on semimetals have high thermal sensitivity, low intrinsic noise and an increased absorption coefficient of radiation in the millimeter region of the spectrum. Samples of bismuth films and bismuth–antimony films were obtained by vacuum thermal spraying. A study was made on the thermoelectric properties of bismuth–antimony thin films in the range from liquid helium temperature to room temperature in order to use these films as a bolometric type sensitive element in the range from infrared to radio frequency. A scheme and description of experimental installations for measuring current-voltage characteristics and determining the resistance of samples in the temperature range 1.4–400 K are presented. In the course of the study, the current-voltage characteristics and the temperature dependences of the resistance of film samples with a thickness of 80 and 20 nm were obtained. The characteristics of the manufactured prototype receiver were measured and used as a basis for estimating the possibility of developing bolometric-type receivers with increased NEP (Noise Equivalent Power). The NEP of the manufactured receivers at a frequency of 147 GHz was measured at room temperature and appeared to be ≈(0.3÷1)∙10 –9 Hz 1/2 . This NEP value can be improved by cooling the receiver to liquid nitrogen or helium temperatures.

Influence of substrate temperature on the morphology and structure of bismuth thin films deposited by magnetron sputtering

The melting point of bismuth is only 271.3 °C which has a great influence on the properties of bismuth itself and the bismuth-contained compounds especially at high temperature. In this paper, the bismuth thin films were prepared using magnetron sputtering method and the influence of deposition temperature on the morphology and structure were investigated over a wide range of substrate temperatures from room temperature to near the melting point. The results showed that 160 °C is a main watershed for the film growth. When the substrate temperature is below 160 °C, the morphology changes a lot from continuous film accumulated mainly by irregular grains to the discontinuous film mainly formed from the isolated polyhedral grains and again to the bimodal grain size distribution of the spherical-polyhedron-shape grains. When the substrate temperature is above 160 °C, the morphology of the bimodal grain size distribution has been maintained except for the changes of the large grain size. The XRD results revealed that the crystallite size hardly changes above 160 °C begin which the bimodal grain size distribution is just formed. The morphology evolution and growth mechanism of bismuth thin films were also studied based on the existing structure zone diagram model and our experimental results.

Effects of Oxygen Ratio on the Properties of Tin Oxide Thin Films Doped with Bismuth

This study examins the effects of the oxygen ratio on the properties of bismuth (Bi)‐doped tin oxide (Bi‐SnOx) films deposited by radio frequency magnetron sputtering using a SnO (90 at%)‐Bi (10 at%) ceramic target. The properties of the samples are characterized by X‐ray photoelectron spectroscopy (XPS), Hall effect measurements, dynamic‐secondary ion mass spectrometry (D‐SIMS), and X‐ray diffraction (XRD). The samples deposited without oxygen gas exhibit Sn4+ and Sn2+ XPS peak areas of 44.7 and 41.1%, respectively. The Sn4+ area increases to 64.1% with increasing oxygen ratio up to 20% with a concomitant decrease of the Sn2+ area to 26%, indicating that SnO2 with n‐type conductivity is the dominant phase under a higher oxygen partial pressure. XPS shows that with increasing oxygen ratio, the chemical state of Bi changes from metallic Bi (Bi0) to Bi3+. Furthermore, with increasing oxygen ratio, the Bi content in the samples increases because of the increase in Bi2O3 formation, which causes a decrease in the number of oxygen vacancies in the samples. These results suggest that the oxygen ratio is useful for controlling Bi doping in SnOx films. Therefore, Bi doping is valuable for suppressing the formation of oxygen vacancies and improving the properties of SnOx films.

A little bit of everything

The properties of bismuth have long defied expectation, casting it just outside the bounds of almost every category. Now topology joins the list, as its electronic structure once deemed trivial turns out to have higher-order topology.

Regulation of the microstructural and optical properties of bismuth ferrite nanowires by mineralizer concentration

Abstract Bismuth ferrite (BiFeO3, or BFO) is a kind of multiferroic material with a single phase. One-dimensional nanomaterials have unique electrical, magnetic, and optical properties due to anisotropy and unique size effects. Bismuth ferrite nanowires were prepared by hydrothermal method processing at different mineralizer concentrations. X-ray diffraction results show that the increase of mineralizer concentration can inhibit the reaction to generate impurities. It can be observed from scanning electron microscopy that along with increasing of mineralizer concentration, the length of the nanowires increase. Transmission electron microscopy and UV–visible spectrophotometry results reveal that the appropriate increase of nanowires length is beneficial to enhancing the absorption of light.

Effect of annealing temperature on microstructure and thermoelectric properties of bismuth–telluride multilayer thin films prepared by magnetron sputtering

N-type bismuth–telluride (Bi–Te) multilayer thin films with total thickness of about 900 nm were deposited on amorphous structure glass substrate by magnetron sputtering at room temperature. The films were annealed at different temperatures under Ar ambient for 1 hour. The effect of annealing temperature was investigated for Bi–Te multilayer thin films by surface topography, chemical composition, crystal structure and thermoelectric properties. The results show that the Bi–Te multilayer thin films are all transformed into Bi–Te-based compounds. With the annealing temperature increasing, the films undergo an island growth mode with column structure, and grain size increases from 16·4 to 23·1 nm; in addition, the electrical conductivity and carrier mobility increase monotonously. The maximum Seebeck coefficient (−98·5 μV K−1) and power factor (14·47 μW K−2 cm−1) can be obtained for stoichiometric Bi2Te3 films annealed at 150°C.

Effect of solvent on nanostructure and thermoelectric properties of bismuth

Nanostructures of bismuth (Bi) are obtained by employing solvothermal process. Two different shapes, nanorods and nanospheres, are produced by changing the ratio of solvents (1) ethylene glycol (EG) and (2) EG and absolute ethanol (AE) in the ratio of 1:1, respectively. Prepared samples are characterized by X-ray diffraction, energy-dispersive X-ray spectroscopy and transmission electron microscopy. Transport properties measured on the pressed pellets of bismuth nanostructures exhibit metallic behavior. The room temperature conductivity varies from 64 to 18 S/cm depending on morphology of the nanostructure. The thermal conductivity is found to be ~50 times lower in nanostructures than that of single crystal bismuth. Thermoelectric performances like power factor and figure of merit are correlated with the porosities of the samples, which show higher value for sphere-like than that of rod-like Bi nanostructures.

Distribution of Bismuth and Bismuth-Related Centers in Core Area of Y-Al-SiO2:Bi Fibers

Analysis of the experimental data on microscopic, absorptive, fluorescent, and Raman-scattering properties of Bismuth (Bi)-doped yttria-alumino-silicate glass (Y-Al-SiO 2 :Bi)-based nanoengineered optical fibers, exhibiting broadband near-infrared fluorescence, is presented. Among the other well-established characteristics, inherent to Bi-doped silica fibers codoped with Aluminum (Al), a trend of spatial distributions of Bi atoms and Bi-related fluorescence-active centers is determined, being their concentrating in ring-like areas around the core's center, at approximately a half-distance to core/cladding interface. At the same time, the formation in this region of nanosized Bi clusters, supposedly weakly or nonfluorescing, is revealed for the fibers. These phenomena are argued to underlie worsening of the pump-to-signal overlap factor, which deteriorates efficiency of lasers and amplifiers based on such or similar Bi-doped alumino-silicate fibers.

Near infrared photoluminescence from bismuth-doped nanoporous silica thin films

Photoluminescence (PL) properties of bismuth (Bi) doped porous silica thin films annealed at various temperatures and in different atmospheres were studied. The near infrared (NIR) luminescence depended strongly on the annealing atmosphere and temperature. To reveal the origin of the NIR luminescence, we performed comprehensive PL studies including steady state and time-resolved PL measurements at 8–300 K in wide excitation (250–500 nm) and detection (400–1550 nm) wavelength ranges. It was revealed that multiple Bi luminescence centers, such as Bi3+, Bi2+, Bi+, and Bi dimer, are stabilized in porous silica.

Diclofenac-Bismuth Complex: Synthesis, Physicochemical, and Biological Evaluation

Diclofenac-bismuth complexation was attempted by mixing diclofenac sodium (Na) and bismuth-subcitrate aqueous solutions at diclofenac:bismuth molar ratio of 3:1. A solid precipitate was obtained and isolated. The precipitate was characterized for stoichiometric ratio of diclofenac-bismuth complexation using capillary electrophoresis, which showed 1:1 complexation. In addition, nuclear magnetic resonance and Fourier transform infrared analysis were performed for the isolated solid complex and indicated that bismuth was in coordinate bond formation with the carboxylate group of diclofenac. In comparison with diclofenac Na powder, the complex was evaluated as an aqueous suspension for in vitro drug dissolution. The complex exhibited a faster dissolution rate than and similar dissolution extent as diclofenac Na. In comparison with an aqueous solution of diclofenac Na and an aqueous suspension of physical mixture of diclofenac acid (suspended) and bismuth-subcitrate (dissolved), the aqueous complex suspension was evaluated for ulcerogenic effect in rats upon oral administration. The complex led to more gastric ulceration than diclofenac Na, which was not in accordance with the antiulcer properties of bismuth. This antiulcer effect was shown as the physical mixture administration was accompanied with lower gastric ulceration than diclofenac Na administration. These gastric ulceration results were explained in terms of the difference in particle size between solid diclofenac acid formed as a result of the complex breakdown in an acidic medium (0.1 M HCl to simulate the gastric fluid) and that formed as a result of diclofenac Na neutralization. Diclofenac acid particles formed from the complex breakdown were of average size, three times smaller of those formed as a result of diclofenac Na protonation. This difference in particle size was correlated with the higher gastric ulceration associated with the complex than with diclofenac Na in terms of higher coverage of the gastric mucosa with diclofenac, and consequently, higher local ulceration.

In-situ TEM Study of Bismuth Nanostructures

AbstractNanostructured thermoelectric materials have attracted lots of interest in recent years, due to their enhanced performance determined by their thermoelectric dimensionless figure of merit. However, because of equipment limitations, not much work has been done on combining simultaneous transport measurements and structural characterization on individual nanostructured thermoelectric materials. With an integrated TEM-STM system, we studied the structural behavior and electrical properties of bismuth (Bi) nanobelts and nanoparticles. Results showed that clean Bi nanostructures free of oxides can be produced by in-situ high temperature electro-migration and Joule annealing processes occurring within the electron microscope. Preliminary electrical measurements indicate a conductivity of two orders of magnitude lower for Bi nanoparticles than that for bulk Bi. Such in-situ studies are highly advantageous for studying the semimetal-semiconductor transition and how this transition could enhance thermoelectric properties.

Low Temperature Microwave Properties of Bismuth Based Dielectric Ceramics

The microwave properties of Bi2(Zn1/3Nb2/3)2O7 and Bi2(Zn1/3Ta2/3)2O7 pyrochlore dielectric ceramics at low temperature were investigated. The ceramic samples were prepared by conventional mixed oxide technology. The structures of the samples were identified as monoclinic pyrochlores. The microwave properties of the cylindrical samples were measured of TE01δ modes at the temperature range of 10 K to 300 K in a cylindrical resonant cavity. The occupying of Nb5+ and Ta5+ in B sites lead different dielectric constants and low temperature dependencies of Q value. A low temperature dielectric anomaly in BZN was observed at 69 K which may be associated with a slight phase transition of the monoclinic pyrochlore Bi2(Zn1/3Nb2/3)2O7 polymorphs. The correlations between the structure, morphology and microwave dielectric properties were discussed.

Study of the effects of additions and isothermal annealing on some physical properties of quenched bismuth–lead solder alloy

Electrical resistivity, hardness, thermal and mechanical properties of bismuth–lead solder alloys with additions such as cadmium, tin or antimony, with and without annealing have been investigated. Adding additions (Sn, Cd, Sb) to a bismuth–lead alloy causes a variation in the internal structure of the Pb–Bi matrix. In addition, annealing causes internal structure changes (migration of grain boundary or coarsening grains), affecting all physical properties such as the resistivity, mechanical and thermal properties. Adding cadmium content to a bismuth–lead alloy increases its electrical resistivity, internal friction, coefficient of thermal expansion (CTE) and hardness and decreases its elastic modulus. However, adding tin increases its resistivity and CTE with a variation in its elastic modulus, internal friction and hardness. In addition, electrical resistivity, hardness and CTE of bismuth–lead alloys increased by adding antimony with decreasing their elastic modulus and internal friction.

Electrical Double Layer on Liquid Bi–Ga Alloys in Aqueous Solutions

Double-layer characteristics of a liquid bismuth–gallium electrode are studied in aqueous electrolyte solutions. Based on the results obtained it is shown that Bi in an alloy with Ga is a surface-active component and forced out to the electrode surface layer. For electrode charges q ≤ –5 μC/cm2, the double layer characteristics of Bi–Ga electrodes approach those of a bismuth electrode. Thus, with respect to its electrochemical properties, a Bi–Ga electrode containing 0.25 at. % Bi simulates a liquid bismuth electrode. The “corrected electrochemical work function” is determined for bismuth. The close values of the difference of zero-charge potentials on mercury and bismuth in water and the difference of “corrected electrochemical work functions” for these metals points to the very low hydrophilicity of the Bi–Ga electrode, which approaches the value for mercury at negative electrode potentials. Taking into account that the Bi–Ga electrode displays no semimetallic properties, the similarity of the electric double layer (EDL) parameters for the Bi–Ga alloy and solid pure Bi indicates that the semimetallic properties of bismuth make no contribution to the EDL characteristics of the alloy in the studied range of negative charges q ≤ –5 μC/cm2.