Room‐Temperature Solution‐Synthesized p‐Type Copper(I) Iodide Semiconductors for Transparent Thin‐Film Transistors and Complementary Electronics

Here, room‐temperature solution‐processed inorganic p‐type copper iodide (CuI) thin‐film transistors (TFTs) are reported for the first time. The spin‐coated 5 nm thick CuI film has average hole mobility (µ_FE) of 0.44 cm² V^?1 s^?1 and on/off current ratio of 5 × 10². Furthermore, µ_FE increases to 1.93 cm² V^?1 s^?1 and operating voltage significantly reduces from 60 to 5 V by using a high permittivity ZrO₂ dielectric layer replacing traditional SiO₂. Transparent complementary inverters composed of p‐type CuI and n‐type indium gallium zinc oxide TFTs are demonstrated with clear inverting characteristics and voltage gain over 4. These outcomes provide effective approaches for solution‐processed inorganic p‐type semiconductor inks and related electronics.     

The CuI-ZnI2 system,Part I: Synthesis and ionic conductivity

Compositions from 90 m/o CuI-10 m/o ZnI₂ to 10 m/o CuI-90 m/o ZnI₂ have been synthesized and studied with differential scanning calorimetry (DSC), X-ray diffraction at room temperature and electronic and ionic conductivity measurements (25 to ～350°C). The compositions with $\text{≧40}\text{m}\text{/}\text{o}$ CuI are solid solutions at room temperature, while disproportionation occurs in the 10 to 30 m/o CuI materials. The electrical conductivities of compositions with $\text{≧60}\text{m}\text{/}\text{o}$ CuI change from mixed to ionic at ～150°C, corresponding to DSC transitions in the same temperature region. These conductivities are higher than that of pure CuI. The highest conductivity, for 80 m/o CuI-20 m/o ZnI₂ (1.8×10^?3 (θ cm)^?1 at 250°C), is about eight times higher than that of CuI.     

Some characteristics of electric explosion of zinc wires

Some physical characteristics necessary for calculating the circuit of and selecting the optimum conditions for the electric explosion of zinc wires have been experimentally determined, including the specific action of zinc h _b = (0.70 ± 0.15) × 10⁵ A² s/mm⁴ (for maximum current densities 2.5 × 10⁵ A/mm² < j _M < 4.5 × 10⁵ A/mm²) and the critical length of exploding wire λ_cr = 1.8 × 10³ (ɛν × 10⁻⁶)^0.56.     

Electrical properties of Sb2O3–CaO–V2O5 glasses and glass-ceramics

The d.c. conductivity (σ) of (a) glasses prepared by the press-quenching method and (b) glass-ceramics (crystallized glass) produced by post-heat treatment was investigated in the system Sb₂O₃–CaO–V₂O₅ and their conduction mechanism was studied. The glasses were n-type semiconductors with σ = 2.6 × 10^-6 ∼ 2.8 × 10^-5 S cm^-1 at 333 K for varying glass compositions. The conduction was attributed to small polaron hopping in the adiabatic regime. The estimated carrier density was 1.7 ∼ 3.8 × 10²¹ cm^-3 for V₂O₅ = 70 ∼ 80 mol% and the mobility was 3.5 × 10^-9 to 6.9 × 10^-8 cm² V^-1 s^-1. Crystallization raised the conductivity by a factor of 10³. The crystalline product in the glass-ceramics was Ca_0.17V₂O₅. The glass-ceramics were n-type semiconductors, and the conduction was interpreted by a superposition of the small polaron hopping in the crystalline and glassy phases. This revised version was published online in November 2006 with corrections to the Cover Date.     

Sorption-atomic-absorption determination of platinum,palladium, and rhodium in dead autocatalysts

The conditions for determination and group concentration of platinum metals (PMs) in the presence of matrix components using new S,N-containing complex-forming sorbents in solutions obtained after decomposition of decontaminated autocatalysts are proposed. The technique of atomic-absorption determination of PMs from a solution (n × 10⁻⁴−n × 10⁻²; s _r = 0.15–0.07) and a solid phase (n × 10⁻⁵−n × 10⁻⁴; s _r = 0.20–0.12) is developed.     

Treatment of gas-air flows to remove radioiodine using metallic copper

A procedure was developed for treatment of gas-air flows to remove radioiodine using metallic copper in the temperature range 200–300°C. The compacted product containing CuI and metallic copper is a stable compound which can be used as a matrix for radioiodine disposal. The rates of iodine leaching from this compound, depending on the weight fraction of the incorporated iodine (from 33.3 to 65.3%), vary in the range from 3.0 × 10⁻⁸ to 6.6 × 10⁻⁸ g cm⁻² day⁻¹, respectively.     

The effect of Leucine on the crystal growth of calcium phosphate

Crystallization kinetics of hydroxyapatite, HAP, in the presence of Leucine, a natural aminoacid with hydrophobic side groups, were investigated at conditions of sustained supersaturation, 37 °C, pH 7.40, ionic strength 0.15 M. In the presence of Leucine, the crystal growth rates of HAP decreased markedly. Τhis action is due to adsorption and subsequent blocking of the active growth sites onto the surface of the HAP crystals. The kinetic results revealed that a Langmuir-type adsorption isotherm is followed and an affinity constants of k _aff = 20.26 × 10² L/mol for HAP crystal surface were calculated. The apparent order of the crystal growth reaction was found to be equal to two, suggesting a surface diffusion controlled mechanism.     

Structure and properties of the layered oxide GdBaFeNiO<Subscript>5 + δ</Subscript>

GdBaFeNiO_5+δ has been synthesized, and its crystal structure, thermal expansion, and electrical properties have been studied. It has a tetragonal structure (sp. gr. P4/mmm) with unit-cell parameters a = 0.3910(2) nm, c = 0.7582(6) nm, and V = 115.9(2) × 10⁻³ nm³ (δ = 0.53) and is a p-type semiconductor. The linear thermal expansion coefficient of GdBaFeNiO_5+δ is 1.32 × 10⁻⁵, 1.72 × 10⁻⁵, and 1.37 × 10⁻⁵ K⁻¹ in the temperature ranges 340–655, 655–870, and 870–1080 K, respectively.     

Frequency-dependent dielectric properties and electrical conductivity of CdIn<Subscript>2</Subscript>S<Subscript>4</Subscript> single crystals

The real (ɛ) and imaginary (ɛ″) parts of complex dielectric permittivity and ac conductivity (σ_ac) of CdIn₂S₄ single crystals (cubic structure) have been measured in the frequency range f = 5 × 10⁴ to 3.5 × 10⁷ Hz. The results demonstrate that the dielectric dispersion in the crystals has a relaxation nature. In the frequency range f = 5 × 10⁴ to 3.5 × 10⁷ Hz, the ac conductivity of single-crystal CdIn₂S₄ follows the relation σ_ac ∼ f ^0.8, characteristic of hopping conduction through localized states near the Fermi level.     

Synthesis and electrochemical application of carbon nanotubes obtained from hexachloroethane

Carbon nanotubes (CNTs) with the average inner (outer) diameter of 10–20 nm (20–40 nm) and length up to 100s of nanometers were synthesized via Wurtz reaction at 400 °C for 12 h, using C₂Cl₆ and Na as reactants. These CNTs, having more defects because of the sp³ bonding raw material of C₂Cl₆, were used as electrode material to detect dopamine (DA) via cyclic voltammetry. The results show that there exists linear relation between peak currents and DA concentration in the range of 2 × 10⁻⁷∼2.8 × 10⁻⁴ mol L⁻¹.The linear regression equation is expressed as Ip (μA) = 0.089 + 0.134c (μmol L⁻¹). This CNTs-modified electrode showed high sensitivity with detection limit of 1 × 10⁻⁷ mol L⁻¹.     

Direct atomic-absorption determination of platinum,palladium, and rhodium in dead ceramic-based autocatalysts

The data on the effect of different concentrations of components of dead automobile catalysts on determination of platinum, palladium, and rhodium using the method of ETAAS are obtained and systematized. The conditions for direct atomic-absorption determination of Pt, Pd, and Rh are optimized. The technique of atomic-absorption determination of PM in secondary raw and technogenic materials is developed (n × 10⁻⁴−n × 10⁻¹ wt %, s _r = 0.12–0.07).     

Molecular analysis of isotopically enriched <Superscript>28</Superscript>SiF<Subscript>4</Subscript> and <Superscript>28</Superscript>SiH<Subscript>4</Subscript> prepared from it

We have developed analytical techniques for the determination of impurities in isotopically enriched ²⁸SiH₄ and ²⁸SiF₄. The impurities in SiF₄ were first determined by IR spectroscopy, and those in SiH₄, by gas chromatography/mass spectrometry. High-sensitivity determination of organic impurities in SiH₄ and SiF₄ was performed by gas chromatography. SiF₄ was found to contain C₁–C₄ hydrocarbons, hexafluorodisiloxane (Si₂F₆O), hydrogen fluoride, trifluorosilanol (SiF₃OH), fluorosilanes, water, and carbon oxides. The impurities identified in SiH₄ include C₁–C₄ hydrocarbons, disilane (Si₂H₆), inorganic hydrides, Si₂H₆O, alkylsilanes, and fluorinated and chlorinated organics. The detection limits of IR spectroscopy were 3 × 10^?3 to 5 × 10^?5 mol %, those of gas chromatography/mass spectrometry were 8 × 10^?6 to 10^?8 mol %, and those of gas chromatography were 6 × 10^-6 to 2 × 10^?7 mol %.     

Optical absorption and photoconductivity in gamma-irradiated zinc selenide crystals

The possibility of radiation-induced enhancement of photoconductivity (σ_ph) in crystalline zinc selenide (ZnSe) has been studied. The electron concentration in the initial ZnSe:O crystal was N _Eg = 1.26 × 10¹⁶ cm⁻³ as determined from the optical density of the sample at E _g = 2.58 eV. The irradiation of the ZnSe:O crystal by gamma-photons from ⁶⁰Co source to a dose of 10⁶ Gy leads to the creation of five new energy levels (Γ_6v, 5.76 eV; L _1.3v, 4.85 eV; Zn_i, 3.34 eV; O_Se, 3.13 eV; X, 2.72 eV), a decrease in the electron concentration to N _Eg = 0.63 × 10¹⁶ cm⁻³, and a twofold increase in σ_ph. The doping with Te to 0.2 wt % also creates the L _1.3v level and increases N _Eg to 2.02 × 10¹⁶ cm⁻³ and σ_ph to 2.01 × 10⁻¹⁰ Ω⁻¹. The irradiation of Te-doped crystals leads to the creation of an additional resonant level (Zn_i, 3.34 eV) and a two-fold increase in σ_ph. An increase in the content of Te to 0.5 wt % results in a shift of the Zn_i level to 3.39 eV and a growth in the conductivity to σ_ph = 7.64 × 10⁻¹⁰ Ω⁻¹. However, the gamma-irradiation of these crystals leads to decomposition of this center and to a decrease in the photoconductivity.     

Electrical properties of iron phthalocyanine thin film device using gold and aluminium electrodes

The electrical conductivity of FePc thin film sandwich structures using gold and aluminium electrodes has been investigated for the freshly prepared devices and device after exposure to oxygen for 30 days. Current density-voltage characteristics of the devices in the forward bias showed an ohmic conduction in lower voltages and a space charge limited conduction (SCLC) controlled by a single and an exponential trapping levels at two different ranges of applied voltages. The hole concentrations are obtained as P _o = 3.92 × 10¹⁶ m⁻³ with a hole mobility μ = 5.81 × 10⁻⁶ m⁻¹ V⁻¹ s⁻¹. In the SCLC region a discrete trap level of 1.88 × 10²¹ m⁻³ is found at 0.66 eV followed by an exponential trap distribution of P _e = 4.63 × 10⁴⁶ J ⁻¹ m⁻³ at N _t(e) = 2.23 × 10²⁶ m⁻³. From the current limitations in the reverse bias, the conduction is identified as an electrode limited Schottky type of conduction. In the oxygen-doped samples, both in the forward and reverse bias the order of currents are much enhanced and a transition from the ohmic conduction to a space charged conduction is observed.     

Preparation of high dispersed nickel pastes for thick film electrodes

Ultra-thinning of Ni paste films for BME-MLCC (Base Metal Electrode Multilayered Ceramic Capacitor) internal electrode was investigated. Adding various dispersants, ball-milling powder, and using the pre-dispersion process to improve Ni paste dispersion and properties of the paste electrodes/thick films, were employed. The paste containing 200 nm sized Ni powders, ethyl cellulose vehicle (η = 2.98 × 10⁴ mPa-s at 0.1 s⁻¹), and Emphos PS-21A as a dispersant proved to be the most desirable candidate. This paste thick film showed the smallest surface roughness (R _a = 0.10 μm and R _max = 0.97 μm) at a viscosity (η = 2.80 × 10⁵ mPa-s at 0.1 s⁻¹) adaptable to screen-printing. In addition, the Ni paste/thick film had the low sheet resistivity (ρ = 1.11 × 10⁻⁴ Ωcm) and an excellent microstructure after sintering at 1,290 °C for 3 h in a 97% N₂/3% H₂ atmosphere.     

Hydrogen permeation through mild steel in temperature range 20–500°C measured by hydrogen collection method

Abstract

Hydrogen permeation through steel plate maintained at various constant temperatures between 20 and 500°C was investigated using the hydrogen collection method. Fused salts were employed at elevated temperatures. Hydrogen entry was induced by step changes in cathodic charging current density. Emanating flux transients obtained at the hydrogen exit face corresponded closely to a model for permeation determined exclusively by bulk hydrogen diffusion through steel, induced by stepped changes in hydrogen concentration at the steel entry face subsurface, and zero hydogen at the exit face subsurface. An Arrhenius plot of log (D) v. 1/T, using diffusion coefficients D derived from permeation transients was approximately linear in the range 20–310°C. The values derived for activation energy E _a of 17 kJ mol ^-1 and for the pre-exponential factor D ₀ of 2·6 × 10^-3 cm2 s^-1, according to D = D ₀ exp (-E _a/RT) were similar to literature values. Between 310 and 500°C, stable permeation conditions were difficult to obtain, but flux measurements were repeatable and unaffected by moisture in air.     

Catalytic reduction of Np(VI) with formic acid in the presence of platinum nanoparticles

The kinetics of catalytic reduction of Np(VI) with formic acid in the presence of Pt nanoparticles of different types (“brown” colloid stabilized with sodium polyacrylate and nonstabilized “gray” colloid) was studied. In both cases in the examined range of conditions ([Np(VI)]₀ = 2.80 × 10^?4?9.03 × 10^?4 M; [HCOOH] = 0.03–1.0 M; [Pt] = 4 × 10^?7 ?2 × 10^?5 M; T = 18–60°C) the reaction is zero-order with respect to [Np(VI)] and first-order with respect to [HCOOH]. The catalytic activity of the nonstabilized “gray” colloid exceeds by almost an order of magnitude that of the “brown” colloid, due to the blocking effect of stabilizing polyelectrolyte molecules on the active catalytic centers. The dependence of the reaction rate on the sodium polyacrylate concentration in the range 1 × 10^?4?1 × 10^?2 M is nonmonotonic, due to deflocculation of the nanoparticles. The mechanism of the catalytic reduction of Np(VI) with formic acid in the presence of Pt colloids is discussed; it involves a slow step of dissociative chemisorption of HCOOH molecules on the nanoparticle surface.     

Water vapor absorption and proton conductivity of (Ba1−x La x )2In2O5+x

The proton conductivity of (Ba_1−x La _x )₂In₂O_5+x system has been investigated as a function of the La content, temperature and amount of absorbed water. The proton conductivity increased with La content up to x = 0.10, to reach a maximum of 1.12 × 10⁻⁵ (S/cm) at 400 °C. From that point on, it decreased. From the results of thermogravimetry and mass spectra, we confirmed that the water was absorbed in the (Ba_1−x La _x )₂In₂O_5+x system, in a maximum quantity of 0.14 mol/mol (sample). The proton conductivity increased monotonically with the quantity of water uptake, suggesting that this variable is one of the dominant parameter of proton conductivity in this system.     

Initial Salt Screening Procedures for Manufacturing Ibuprofen

The aim of this paper is to design initial salt screening procedures for manufacturing ibuprofen. Salt forms of a pharmaceutical acid racemic (R,S)-(±)-ibuprofen and their “developable” synthetic routes were ferreted out simultaneously through the screening of seven bases of sodium hydroxide, potassium hydroxide, l-arginine, l-histidine, l-lysine, diethanolamine, and tris(hydroxymethyl)aminomethane (THAM), and the match with the use of nine organic solvents of methanol, dimethyl sulfoxide, ethanol, N,?N-dimethylformamide, acetonitrile, isopropyl alcohol, 1,4-dioxane, acetone, and tetrahydrofuran mainly in the presence of water in 20 mL scintillation vials. Racemic (R,S)-(±)-sodium ibuprofen dihydrate, a well-known ibuprofen salt and the newly discovered racemic (R,S)-(±)-THAM ibuprofen, appeared as white-squared powders with a molecular weight of 327.42 g/mol, a melting point of 160.17°C, and the apparent solubility product, K′_sp, of 6.0 × 10^?4 M² at 25°C were successfully synthesized by the initial salt screening methods. The new amine salt of ibuprofen was monoclinic and had a space group of P2₁/c and lattice parameters of a = 17.578(8)°, b = 10.428(4)°, c = 9.991(4) Å, α = 90.00°, β = 97.17(1)°, γ = 90.00°, and V = 1,817.05(244) ų. The aspect ratio of the amine salt crystals of ibuprofen of ≈ 1.0 implied that the crystals had a better flowability than the sodium salt counterparts. This amine salt of ibuprofen was more stable in moist or dried atmospheres and was more hydrophobic than the sodium salt of ibuprofen. Moreover, the slow dissolution of this amine salt of ibuprofen might have made it less bitter and more suitable as a sustained release drug than the sodium salt of ibuprofen. The future work is to search for the different polymorphs of this amine salt of ibuprofen and to extend the initial salt screening working logics to the formation of co-crystals.     

Hydrogen-Doping-Induced Metal-Like Ultrahigh Free-Carrier Concentration in Metal-Oxide Material for Giant and Tunable Plasmon Resonance

The practical utilization of plasmon-based technology relies on the ability to find high-performance plasmonic materials other than noble metals. A key scientific challenge is to significantly increase the intrinsically low concentration of free carriers in metal-oxide materials. Here, a novel electron–proton co-doping strategy is developed to achieve uniform hydrogen doping in metal-oxide MoO₃ at mild conditions, which creates a metal-like ultrahigh free-carrier concentration approaching that of noble metals (10²¹ cm⁻³ in H_1.68MoO₃ versus 10²² cm⁻³ in Au/Ag). This bestows giant and tunable plasmonic resonances in the visible region to this originally semiconductive material. Using ultrafast spectroscopy characterizations and first-principle simulations, the formation of a quasi-metallic energy band structure that leads to long-lived and strong plasmonic field is revealed. As verified by the surface-enhanced Raman spectra (SERS) of rhodamine 6G molecules on H_xMoO₃, the SERS enhancement factor reaches as high as 1.1 × 10⁷ with a detection limit at concentration as low as 1 × 10⁻⁹ mol L⁻¹, representing the best among the hitherto reported non-metal systems. The findings not only provide a set of metal-like semiconductor materials with merits of low cost, tunable electronic structure, and plasmonic resonance, but also a general strategy to induce tunable ultrahigh free-carrier concentration in non-metal systems.