Loss Of Bi Research Articles

Interface microstructures in the wetting of Cu by equiatomic GaInSnBiZn high-entropy alloy

This study investigates the wetting characteristics, interface microstructure evolution of equiatomic GaInSnBiZn HEA on Cu under high vacuum with sessile drop method to extend its electronic packaging applications. Optimal conditions involve a 350 °C temperature maintained for ∼20 min to prevent Bi loss, resulting in a contact angle inversely proportional to temperature and reaching a minimum of ∼15.6°. A dual-layer of Cu9Ga4 and CuGa2 forms at the HEA/Cu interface, consistent with thermodynamic predictions, featuring lower activation energy and growth driven by bulk alloy diffusion. Base on the interface microstructures, Cu9Ga4 and CuGa2 act as diffusion barriers, restricting the movement of other elements while promoting the accumulation of Zn at the interface. The wetting mechanism may be determined by the oxide (Cu2O) removal reaction (i.e., reaction between Ga and Cu2O).

Room temperature magneto-dielectric coupling in the CaMnO3 modified NBT lead-free ceramics

The sol–gel prepared (1-x)Na0.5Bi0.5TiO3-(x) CaMnO3 (x = 0, 0.03, 0.06, 0.12) compositions show a Rhombohedral (R3c) phase up to x = 0.06 while a mixed rhombohedral (R3c) and orthorhombic (Pnma) phases for the x = 0.12. The lattice volume consistently decreased with an increase in the CaMnO3 content. The phase transition temperature (Tc) decreased with an increase in the CaMnO3 compositions. The room temperature dielectric constant increased, and loss decreased for the x = 0.03 composition due to a decrease in the oxygen vacancy and Bi loss confirmed by the valence state study (XPS). All the compositions show a variation of the room temperature dielectric property with an application of magnetic field confirming a magnetodielectric coupling. The x = 0.06 composition shows the highest negative magnetodielectric coupling constant (MD%) of 3.69 at 100 kHz at an applied field of 5 kG.

Promoted Carbon Monoxide Sensing Performance of a Bi2Mn4O10-Based Mixed-Potential Sensor by Regulating Oxygen Vacancies.

The YSZ-based mixed-potential sensor has exhibited promising application prospects for in situ carbon monoxide (CO) monitoring owing to its excellent thermal stability. However, the way to further enhance the sensitivity and selectivity of the sensor remains challenging due to the limitation of the sensing material. In the present work, we proposed a strategy of introducing moderate oxygen vacancies in the transition metal oxide sensing material to enhance CO sensing performance. More importantly, the oxygen vacancies of the sensing electrode were regulated by adjusting the volatilization of the Bi element at different sintering temperatures. Meanwhile, the stable mullite structure and variable valency of Mn were also exploited to maintain the phase structure stability and charge balance brought by the loss of Bi. The relationship between CO sensing properties and the proportion of both Mn3+/Mn4+ and oxygen vacancies was elucidated from XPS and EIS measurements. By contrast, the 800 °C-sintered Bi2Mn4O10 possesses the highest oxygen vacancy content and thus exhibits preferable sensing performance including a lower detecting limit (10 ppm), swifter response/recovery processes, and enhanced CO sensitivity (-70.47 mV/decade operated at 450 °C) with satisfactory selectivity and stability, indicating a promising prospect for CO monitoring under exhaust environments.

Global-Scale Assessment of Economic Losses Caused by Flood-Related Business Interruption

Estimating river flood risk helps us to develop strategies for reducing the economic losses and making a resilient society. Flood-related economic losses can be categorized as direct asset damage, opportunity losses because of business interruption (BI loss), and high-order propagation effects on global trade networks. Biases in meteorological data obtained from climate models hinder the estimation of BI loss because of inaccurate input data including inundation extent and period. In this study, we estimated BI loss and asset damage using a global river and inundation model driven by a recently developed bias-corrected meteorological forcing scheme. The results from the bias-corrected forcing scheme showed an estimated global BI loss and asset damage of USD 26.9 and 130.9 billion (2005 purchase power party, PPP) (1960–2013 average), respectively. Although some regional differences were detected, the estimated BI loss was similar in magnitude to reported historical flood losses. BI loss tended to be greater in river basins with mild slopes such as the Amazon, which has a long inundation period. Future flood risk projection using the same framework under Representative Concentration Pathway 8.5 (RCP8.5) and Shared Socioeconomic Pathway 3 (SSP3) scenarios showed increases in BI loss and asset damage per GDP by 0.32% and 1.78% (2061–2090 average) compared with a past period (1971–2000 average), respectively.

Defect dipole induced improved electrocaloric effect in modified NBT-6BT lead-free ceramics

The Rietveld refinement of the polycrystalline powders of 1% Fe and Mn-doped (Na0.5Bi0.5)0.94Ba0.06Ti0.98V0.02O3 at the Ti-site confirmed a single rhombohedral (R3c) phase. The bandgap, (Eg) was affected by the anti-phase octahedral tilt angle and the spin-orbit splitting energy of Ti4+2p3/2 and Ti4+2p1/2 states. The decrease in Bi loss and increase in the binding energy of Ba due to Fe/Mn doping has been correlated to the strengthening of Bi-O and Ba-O bonds which was revealed from the XPS studies thereby further related to the average A-O bond length from structural studies. Hence, a reduction of oxygen vacancy (VO) for the doped samples has been justified. A significant improvement of the dielectric constant, relaxation time (τ0), and the decrease in conductivity due to doping was revealed from the frequency-dependent (10 Hz-1 MHz) dielectric measurement study. The conduction and relaxation process are dominated by the short-range movement of defects. The activation energy (Ea~1 eV) revealed that there is a presence of double-ionized VOs. The ECE study showed a significant enhancement of the changes in entropy, ΔS, and the adiabatic temperature difference, ΔT, due to doping, with ΔT being highest in the Fe-doped sample. Such improvement of dielectric and ECE properties was confirmed due to the reduction of the mobility of oxygen vacancy because of the formation(MnTi′′−Vo••)/(MnTi′−Vo••)• and FeTi′′−Vo••/(FeTi′−Vo••)• defect dipoles.

Performance evaluation of lead–free double-perovskite solar cell

This article presents the numerical simulation of lead–free (Pb-free) double–perovskite (Cs 2 AgBi 0.75 Sb 0.25 Br 6 , i.e., mixed antimony bismuth halide double-perovskite) solar cell (DPSC) using solar cell capacitance one dimensional simulator (SCAPS-1D). In this contribution, the hole transport layers (HTLs) and electron transport layers (ETLs) are optimized. The optimization is performed by correlating the open circuit voltage (V OC ) with the built-in potential (V bi ). It is disclosed from the simulation results, that higher V bi resulted higher V OC . Furthermore, it is also found that, for the proper selection of HTL, the E V_HTL (Valence band maximum of HTL) and φ BC (Work function of back contact) should not be much deeper than the E V_PVK (Valence band maximum of double–perovskite layer) to avoid V bi loss. Correspondingly, for proper selection of ETL, E C_ETL (Conduction band minimum of electron transport layer) and Φ FC (Work function of front contact), should not be much higher than E C_PVK to prevent V bi loss. The optimized HTL and ETL are found to be Cu 2 O (copper(I) oxide) and ZnOS (Zinc oxysulfide) respectively. Moreover, the device photovoltaic performance is further improved by optimizing the double-perovskite layer thickness which is found to be 400 nm. Under optimized condition, the device photovoltaic power conversion efficiency (η) improves to 18.18%. The optimized device photovoltaic performance are found to be, open –circuit voltage (Voc) = 1.39 V, short-circuit current density (J SC ) = 16.04 mA/cm 2 , and fill factor (FF) = 78.34% which indicates that double–perovskite absorber layer (Cs 2 AgBi 0.75 Sb 0.25 Br 6 ) is a suitable candidate for the development of highly efficient Pb-free DPSC. • The numerical simulation of lead-free double–perovskite is performed with-optimized device efficiency of 18.18%. • The electron transport layer and hole transport layer is optimized by co-orelating V OC with V bi . • The simulation study reveals that V OC is strongly dependent on V bi of lead-free double –perovskite absorber layer. • The optimized ETL and HTL found to be ZnOS and Cu 2 O respectively.

Structural and electrical properties of Bi(Mg0.5Ti0.5)O3 ceramic

Bismuth magnesium titanate Bi(Mg0.5Ti0.5)O3 ceramic, fabricated by ceramic processing technique, has been characterized using various experimental techniques. Analysis of basic crystal structure using X-ray diffraction data has exhibited the orthorhombic system as a major phase. Microstructural analysis provided the quality of the sample. Detailed studies of electrical properties (dielectric constant, tangent loss, electrical modulus, conductivity and impedance) of Bi(Mg0.5Ti0.5)O3 in a wide range of frequency (1 kHz–1 MHz) and temperature (25–480 °C) have provided various interesting results on antiferroelectric characteristics, conduction mechanism, structure–properties relationship, etc. An important role of interface in getting high dielectric material has been realized. The space charge polarization and Maxwell–Wagner dielectric relaxation in the material, particularly at low frequencies and high temperatures. Nyquist plots discuss the temperature-dependent contributions of grain effect. The frequency of the applied electric field and temperature strongly affect the electrical (AC) conductivity and transport properties of the material studied, and exhibiting semiconductor characteristics.

Microwave dielectric properties of Bi(Sc1/3Mo2/3)O4 ceramics for LTCC applications

A novel microwave dielectric ceramics Bi(Sc1/3Mo2/3)O4 with low firing temperature were prepared via the solid reaction method. The specimens have been characterized using scanning electron microscopy, X-ray diffraction, Raman spectroscopy and DC conductivity. The Bi(Sc1/3Mo2/3)O4 ceramics showed B-site ordered Scheelite-type structure with space group C2/c. Raman analysis indicated that prominent bands were attributed to the normal modes of vibration of MoO4 2− tetrahedra. The dielectric loss of Bi(Sc1/3Mo2/3)O4 ceramics can be depended strongly the bulk conductivity by DC measurement. The superior microwave dielectric properties are achieved in the Bi(Sc1/3Mo2/3)O4 ceramic sintered at 875 °C/4 h, with dielectric constant ~ 25, Q × f ~ 51,716 GHz at 6.4522 GHz and temperature coefficient of resonance frequency ~ − 70.4 ppm/°C. It is a promising microwave dielectric material for low-temperature co-fired ceramics technology.

Structural transformation and multiferroic properties of Sm and Ti co-doped BiFeO3 ceramics with Fe vacancies

Abstract Sm and Ti co-doped BiFeO 3 (BFO) ceramics with Fe vacancies—Bi 0.86 Sm 0.14 FeO 3 , Bi 0.86 Sm 0.14 Fe 0.99 Ti 0.01 O 3 , and Bi 0.86 Sm 0.14 Fe 0.9 Ti 0.05 O 3 —were prepared by a solid-state method using a rapid liquid process. X-ray diffraction indicated that all samples exhibited a rhombohedral structure with a minor secondary phase. The structural transformation from a rhombohedral (space group: R 3 c ) to orthorhombic structure (space group: Pnma ) was observed in the sample of Bi 0.86 Sm 0.14 Fe 0.9 Ti 0.05 O 3 , which was also confirmed by Raman scattering spectra. Microstructural investigations with scanning electron microscopy showed a reduction in grain size with doping of BFO. The dielectric loss of Bi 0.86 Sm 0.14 Fe 0.9 Ti 0.05 O 3 reaches 0.05 (at 100 Hz) owing to the introduction of Ti and Fe vacancies. Ferroelectromagnetic measurements revealed the existence of ferroelectricity with a remanent polarization of 0.24 µC/cm 2 in Bi 0.86 Sm 0.14 FeO 3 , paraelectricity in Bi 0.86 Sm 0.14 Fe 0.9 Ti 0.05 O 3 , and weak ferromagnetism with a remanent magnetization of 0.2 emu/g in Bi 0.86 Sm 0.14 Fe 0.99 Ti 0.01 O 3 . The two composition-driven phases exist simultaneously and the different coercive field might be related to the jumps in the ferromagnetic hysteresis loops. Both the ferroelectric and magnetic properties were shown to correlate with the composition-driven structural evolution.

Bismuth Doping of Germanium Nanocrystals through Colloidal Chemistry

Nanogermanium is a material that has great potential for technological applications, and doped and alloyed Ge nanocrystals (NCs) are actively being considered. New alloys and compositions are possible in colloidal synthesis because the reactions are kinetically rather than thermodynamically controlled. Most of the Group V elements have been shown to be n-type dopants in Ge to increase carrier concentration; however, thermodynamically, Bi shows no solubility in crystalline Ge. Bi-doped Ge NCs were synthesized for the first time in a microwave-assisted solution route. The oleylamine capping ligand can be replaced by dodecanethiol without loss of Bi. A positive correlation between the lattice parameter and the concentration of Bi content (0.5–2.0 mol %) is shown via powder X-ray diffraction and selected area electron diffraction. X-ray photoelectron spectroscopy, transmission electron microscopy (TEM), scanning TEM, and inductively coupled plasma–mass spectroscopy are consistent with the Bi solubility up to ...

Significantly enhanced piezoelectricity in low-temperature sintered Aurivillius-type ceramics with ultrahigh Curie temperature of 800 °C

We report an Aurivillius-type piezoelectric ceramic (Ca1−2x (LiCe)xBi4Ti3.99Zn0.01O15) that has an ultrahigh Curie temperature (Tc) around 800 °C and a significantly enhanced piezoelectric coefficient (d33), comparable to that of textured ceramics fabricated using the complicated templating method. Surprisingly, the highest d33 of 26 pC/N was achieved at an unexpectedly low sintering temperature (Ts) of only 920 °C (~200 °C lower than usual) despite the non-ideal density. Study of different synthesized samples indicates that a relatively low Ts is crucial for suppressing Bi evaporation and abnormal grain growth, which are indispensable for high resistivity and effective poling due to decreased carrier density and restricted anisotropic conduction. Because the layered structure is sensitive to lattice defects, controlled Bi loss is considered to be crucial for maintaining structural order and spontaneous polarization. This low-Ts system is very promising for practical applications due to its high piezoelectricity, low cost and high reproducibility. Contrary to our usual understanding, the results reveal that a delicate balance of density, Bi loss and grain morphology achieved by adjusting the sintering temperature is crucial for the enhancing performance in Aurivillius-type high-Tc ceramics.

Bismuth-doped germanate glass fiber fabricated by the rod-in-tube technique

Bismuth (Bi)-doped laser glasses and fiber devices have aroused wide attentions due to their unique potential to work in the new spectral range of 1 to 1.8 μm traditional laser ions, such as rare earth, cannot reach. Current Bi-doped silica glass fibers have to be made by modified chemical vapor deposition at a temperature higher than 2000°C. This unavoidably leads to the tremendous loss of Bi by evaporation, since the temperature is several hundred degrees Celsius higher than the Bi boiling temperature, and, therefore, trace Bi (∼50 ppm) resides within the final product of silica fiber. So, the gain of such fiber is usually extremely low. One of the solutions is to make the fibers at a temperature much lower than the boiling temperature of Bi. The challenge for this is to find a lower melting point glass, which can stabilize Bi in the near infrared emission center and, meanwhile, does not lose glass transparency during fiber fabrication. None of previously reported Bi-doped multicomponent glasses can meet the prerequisite. Here, we, after hundreds of trials on optimization over glass components, activator content, melting temperature, etc., find a novel Bi-doped gallogermanate glass, which shows good tolerance to thermal impact and can accommodate a higher content of Bi. Consequently, we successfully manufacture the germanate fiber by a rod-in-tube technique at 850°C. The fiber exhibits similar luminescence to the bulk glass, and it shows saturated absorption at 808 nm rather than 980 nm as the incident power becomes higher than 4 W. Amplified spontaneous emissions are observed upon the pumps of either 980 or 1064 nm from germanate fiber.

Effect of synthesis route on the multiferroic properties of BiFeO3: A comparative study between solid state and sol–gel methods

Polycrystalline BiFeO3 (BFO) powder was prepared through optimized solid state (SS) and sol–gel (SG) reaction methods. The effect of preparation routes on the crystal purity and multiferroic properties of the BFO was investigated. Sol–gel synthesis results almost a single-phase material at relatively lower temperatures while the solid-state method results into BFO with a small amount of Bi2Fe4O9 secondary phase. The grain size of SG processed sample reduces to half the size of the one that is prepared by SS. Elemental analysis shows a stoichiometric Bi:Fe content for SG samples by restricting the Bi loss. In comparison with the SS samples, dielectric constant of SG samples exhibit higher values with Maxwell–Wagner type dielectric dispersion. A cusp at 50 K was seen in M–T curves for SS samples, for which no frequency dependence was observed in a.c susceptibility measurements ruling out the earlier predictions of spin glass nature in this system. M−H loops show a typical antiferromagnetic nature at 300 K while a weak ferromagnetic behavior is found at 10 K. A slight increase in HC and Mr was observed for SG samples over SS. The improved properties of SG processed BFO makes it more promising for applications.

Influence of Na/Bi excess on structural, dielectric and multiferroic properties of lead free (Na0.5Bi0.5)0.99La0.01Ti0.988Fe0.012O3 ceramic

(Na0.5Bi0.5)0.99La0.01Ti0.988Fe0.012O3 (NBLTF) ceramic has been prepared by sol–gel method without and with 10mol% excess of Na and Bi. Structural analysis of NBLTF samples has been carried out by XRD, FT-IR and Raman spectra. X-ray diffraction patterns of NBLTF samples confirm single phase perovskite structure having rhombohedral symmetry. FT-IR and Raman spectra exhibit similar characteristic bands for both NBLTF samples which confirm the formation of perovskite structure. Comparatively high intensity and shifting of Raman bands in NBLTF sample having excess mol% of Na and Bi suggest dense crystal growth which is consistent with microstructural properties of the sample and density measurements. Bi loss during sintering process and the dense crystal growth is reported to affect the dielectric, magnetic and ferroelectric properties in synthesized samples.

Preparation and Characterization on Piezo-/Ferro-electric Properties of (1-x)(KNN+LT)+xBI Ceramics

Lead free ferroelectric ceramics, (1-x)(0.97Na0.5K0.5NbO3+0.03LiTaO3)+xBiInO3((1-x)(KNN+LT)+xBI) ternary solid solution system were prepared by conventional solid state reaction method. The polycrystal structure, dielectric and piezo-/ferro-electric properties were systematically characterized. The results show that the (1-x)(KNN+LT)+ xBI ceramics present pure perovskite structure in which the orthorhombic and tetragonal phases coexist at room temperature. With increasing of BI content, the tetragonal phase and the lattice parameter increase gradually and the Curie temperature Tc decreases, while the phase transition temperature To-t from orthorhombic to tetragonal phase increases. With more BI addition, the electric properties decrease with the appearance of oxygen vacancy due to Bi loss at high temperature. The optimal properties are achieved in the (1-x)(KNN+LT)+xBI ceramics (x=0.0015) with the Curie temperature Tc= 400℃, phase transition temperature To-t =126℃, piezoelectric constant d33 =160 pC/N, remnant polarization Pr=19.26 μC/cm 2 and coercive field Ec =7.75 kV/cm.

The magnetoelectric properties of A- or B-site-doped PbVO3 films: A first-principles study

We employ first-principles calculations to study the magnetic and ferroelectric properties of PbVO3 with A (XA = Ca, Sr, Bi, Ba, and La) or B (XB = Ti, Cr, Mn, Fe, Co, Ni, and Cu) site dopants, with the aim of ascertaining a large ferroelectric polarization and a long magnetic order, or even a macro ferri/ferromagnetism, which is critical to their potential applications in magnetoelectronic devices. It is found that Pb7XAV8O24 (XA = Ca, Sr, and Ba,) are inclined to maintain the spin glass and large ferroelectric polarization. The degenerated G- and C-antiferromagnetic (AFM) couplings in the ideal PbVO3 are broken up, accompanied by the loss of ferroelectric properties, when La or Bi is doped at the A site. In contrast, the above-mentioned 3d transition elements doped at the B site of PbVO3 could induce remnant magnetic moments and preserve the large ferroelectric polarization, except for Ni and Cu. The Fe or Cr at the B site clearly remove the degenerated G- and C-AFM coupling, but the nonmagnetic Ti cannot do so. For the Mn, Co, Ni, or Cu doped at the B sites, even the two-dimensional AFM ordering in PbVO3 is destabilized. The various doping effects are further discussed with inner strain and charge transfer.

Formation of Cu3BiS3 thin films via sulfurization of Bi–Cu metal precursors

Thin films of Cu3BiS3 have been produced by conversion of stacked and co-electroplated Bi–Cu metal precursors in the presence of elemental sulfur vapor. The roles of sulfurization temperature and heating rate in achieving single-phase good quality layers have been explored. The potential loss of Bi during the treatments has been investigated, and no appreciable compositional difference was found between films sulfurized at 550 °C for up to 16 h. The structural, morphological and photoelectrochemical properties of the layers were investigated in order to evaluate the potentials of the compound for application in thin film photovoltaics.

Electrical behavior of high resistivity Ce-doped BiFeO3 multiferroic

Bi1+xCexFeO3 (Ce–BFO) for x=0, 0.05, 0.1, and 0.15 monophasic ceramic samples were successfully synthesized by conventional solid-state reaction routes. The influences of Ce doping on structural, dielectric, ferroelectric, leakage current and capacitive properties of BiFeO3 ceramics were investigated intensively. At higher concentrations of x (x=0.1 and 0.15) the samples showed good crystallinity with almost impurity free phases. No structural phase transformation took place after partial doping of Ce ions and all ceramic bulk samples remain in their rhombohedral structure with space group R3c. The dielectric behavior of the samples improved significantly and the ferroelectric hysteresis loops changed their shape from rounded to a strongly nonlinear typical ferroelectric feature mainly originating from the domain switching and became enhanced with increase in doping concentration of cerium (Ce). Experimental results also suggested that partial doping of higher valence, smaller ionic radius Ce ions in BiFeO3 forces the reduction of oxygen vacancies, resulting in a great suppression of leakage current. It is found that the sharp capacitance peak/discontinuity present in the C–V characteristics of Ce–BFO for different Ce doping concentrations is directly associated with the polarization reversal. Incorporation of excess bismuth in the presence of Ce in BiFeO3 is expected to compensate Bi loss during high temperature sintering and caused structural distortion which also favors enhancement of ferroelectric properties in Ce-doped BFO.

Microstructure and electrical properties of (Bi0.50+xNa0.50)0.94Ba0.06TiO3 ceramics with bismuth nonstoichiometry

AbstractA way to improve the piezoelectric properties of (Bi, Na)TiO3 ceramics is developed by suppressing the evaporation of Bi, and (Bi0.50+xNa0.50)0.94Ba0.06TiO3 (BNBT‐x) ceramics were prepared by the conventional solid‐state method. The effect of Bi nonstoichiometry on the microstructure and electrical properties of BNBT‐x ceramics was investigated. A lower Tm value is demonstrated for BNBT‐x ceramics with Bi nonstoichiometry, and a typical relaxor behavior is observed for BNBT‐x ceramics with excessive Bi. The ceramic with x = 0.01 has higher density and resistivity, and a macroscopic polarization can be induced that consequently can be subject to depolarization at a depolarization temperature. BNBT‐x ceramics with Bi deficiency have a lower dielectric loss than that of those ceramics with Bi excess, while a smaller dielectric constant is observed for those ceramics with Bi deficiency. An enhanced piezoelectric behavior of d33 ∼ 166 pC/N, k33∼43.0%, kp∼33.9%, and Td ∼ 92 °C has been demonstrated for the ceramic with x = 0.01. As a result, this is an effective way to improve the piezoelectric properties of (Bi, Na)TiO3 ceramics by compensating the loss of Bi.

Improvement of multiferroic and leakage property in monophasic BiFeO 3

This paper aims to report that impurity phase free single phase multiferroic BiFeO 3 ceramic can be prepared by critically optimizing the metal ion concentration using slow step sintering schedule at 850 °C for 24 h. Antiferromagnetic character of pure BiFeO 3 is completely changed and ferromagnetic behavior observed with increase of Bi as well as decrease of Fe concentration. It is found that Bi rich (Bi: 1.2) Fe deficient (Fe: 0.8) composition produces single phase rhombohedral structure with space group R3c along with enhanced ferroelectric and ferromagnetic properties. Incorporation of excess bismuth caused structural distortion and expected to compensate Bi loss during high temperature sintering. On the other hand, iron deficient helps the formation of Fe 3+ state, which hinders the creation of oxygen vacancies and also favors the reduction of leakage current. Structural distortion in BiFeO 3 changes Fe–O–Fe bond angle or spin order, destructs the spin cycloid and releases a locked magnetization.