Superconducting epitaxial $$\hbox {YBa}_{2}\hbox {Cu}_{3}\hbox {O}_{7-\delta }$$ on $$\hbox {SrTiO}_{3}$$SrTiO3-buffered Si(001)

Thin films of optimally doped(001)-oriented \(\hbox {YBa}_{2}\hbox {Cu}_{3}\hbox {O}_{7-\updelta }\) are epitaxially integrated on silicon(001) through growth on a single crystalline \(\hbox {SrTiO}_{3}\) buffer. The former is grown using pulsed-laser deposition and the latter is grown on Si using oxide molecular beam epitaxy. The single crystal nature of the \(\hbox {SrTiO}_{3}\) buffer enables high quality \(\hbox {YBa}_{2}\hbox {Cu}_{3}\hbox {O}_{7-\updelta }\) films exhibiting high transition temperatures to be integrated on Si. For a 30-nm thick \(\hbox {SrTiO}_{3}\) buffer, 50-nm thick \(\hbox {YBa}_{2}\hbox {Cu}_{3}\hbox {O}_{7-\updelta }\) films that exhibit a transition temperature of \(\sim \)93 K, and a narrow transition width (<5 K) are achieved. The integration of single crystalline \(\hbox {YBa}_{2}\hbox {Cu}_{3}\hbox {O}_{7-\updelta }\) on Si(001) paves the way for the potential exploration of cuprate materials in a variety of applications.     

Inhomogeneous Superconducting Behaviour in $$\hbox {La}_{5}\hbox {Ni}_{2}\hbox {Si}_{3}$$

The superconducting phase transition at \(T_\mathrm{c} = 2.3\) K was observed for the electrical resistivity \(\rho ({T})\) and magnetic susceptibility \(\chi (T)\) measurements in the ternary compound La\(_{5}\hbox {Ni}_{2}\hbox {Si}_{3}\) that crystallizes in the hexagonal-type structure. Although a single-phase character with the nominal stoichiometry of the synthesized sample was confirmed, a small trace of the La–Ni phase was found, being probably responsible for the superconducting behaviour in the investigated compound. The magnetization loop recorded at \({T} = 0.5\) K resembles a star-like shape which indicates that the density of the critical current can be strongly suppressed by a magnetic field. The low-\(T _{\rho }(T)\) and specific heat \({C}_\mathrm{p}({T})\) data in the normal state reveal simple metallic behaviour. No clear evidence of a phase transition to any long- or short-range order was found for \(C_\mathrm{p}(T)\) measurements in the T-range of 0.4–300 K.     

Correlations for the Dielectric Constants of $$\hbox {H}_{2}\hbox {S}$$, $$\hbox {SO}_{2}$$SO2, and $$\hbox {SF}_{6}$$SF6

A new method is developed for correlating the static dielectric constant of polar fluids over wide ranges of conditions where few experimental data exist. Molecular dynamics simulations are used to establish the temperature and density dependence of the Kirkwood g-factor, and also the functional form for the increase of the effective dipole moment with density. Most parameters in the model are obtained entirely from simulation; a single proportionality constant is adjusted to obtain agreement with the limited experimental data. The method is applied to hydrogen sulfide (\(\hbox {H}_{2}\hbox {S}\)) and sulfur dioxide \((\hbox {SO}_{2})\), both of which are important in geochemistry but have only a few dielectric data available. The resulting correlations agree well with the available liquid data, obey physical boundary conditions at low density and at high temperature, and interpolate in density and temperature in a physically reasonable manner. In addition, we present a more conventional correlation for the dielectric constant of sulfur hexafluoride, \(\hbox {SF}_{6}\), where more data are available.     

Thermal Emittance of $$\hbox {La}_{0.7}\hbox {Ca}_{0.3-x}\hbox {K}_x\hbox {MnO}_3$$ Coatings on Aluminum Substrate

A novel thermal control coating was presented based on the thermochromism of manganite. The pigment of K-doped manganite nanoparticles was dispersed into polymer matrix to prepare the coating with curing below 200 \(^{\circ }\)C. The nanoparticles size mainly distributes around 100–200 nm, and it shows a comparable stoichiometric ratio. The phase transition of the nanoparticles was observed from ferromagnetic metallic to paramagnetic insulator state. With increasing K doping level, the phase transition temperature increases, achieving controllable adjustment. Coating surface with and without pore defect was obtained by different polymer matrix. A sharp emittance variation was observed with increasing temperature in K-doped coating. The variation magnitude of emittance is up to 0.46, which is attractive to space thermal control. It is suggested that the pigment content of 50 wt% is sufficient to realize a large emittance variation.     

Radiative Properties of Ceramic $$\hbox {Al}_{2}\hbox {O}_{3}$$, AlN,and $$\hbox {Si}_{3}\hbox {N}_{4}$$Si3N4: I. Experiments

The radiative properties of dense ceramic \(\hbox {Al}_{2}\hbox {O}_{3}\), AlN, and \(\hbox {Si}_{3}\hbox {N}_{4}\) plates are investigated from the visible to the mid-infrared region at room temperature. Each specimen has different surface finishings on different sides of the laminate. A monochromator was used with an integrating sphere to measure the directional-hemispherical reflectance and transmittance of these samples at wavelengths from 0.4 \(\upmu \hbox {m}\) to 1.8 \(\upmu \hbox {m}\). The specular reflectance was obtained by a subtraction technique. A Fourier-transform infrared spectrometer was used to measure the directional-hemispherical or specular reflectance and transmittance with appropriate accessories from about 1.6 \(\upmu \hbox {m}\) to 19 \(\upmu \hbox {m}\). All measurements were performed at near-normal incidence on either the smooth side or the rough side of the sample. The experimental observations are qualitatively interpreted considering the optical constants, surface roughness, and volume scattering and absorption.     

Evolution of the electrical resistance of \bf{\hbox {YBa}_2\hbox {Cu}_3\hbox {O}_{7-\varvec\delta }} single crystals in the course of long-term aging

Investigated are the changes in the basal-plane electrical resistivity of an optimally doped \(\hbox {YBa}_2\hbox {Cu}_3\hbox {O}_{7-\delta }\) single crystal in the course of long-term aging (17 years) at room temperature in air. In consequence of aging the sample has decomposed into three phases with different temperatures of the superconducting transition, while the transition widths of these phases have increased significantly. The temperature dependence of the electrical resistivity has retained a metallic character. The fluctuation conductivity near the critical temperature is described well by the 3D Aslamazov–Larkin model. In the course of aging significant changes in the scattering characteristics have been observed, whereas the Debye temperature has changed slightly and the transverse coherence length has remained constant.     

Effect of Hafnium Impurities on the Magnetoresistance of $$\hbox {YBa}_{2}\hbox {Cu}_{3}\hbox {O}_{7-\delta }$$

In the present study, we investigate the influence of the hafnium (Hf) impurities on the magnetoresistance of \(\hbox {YBa}_{2}\hbox {Cu}_{3}\hbox {O}_{7-\delta }\) ceramic samples in the temperature interval of the transition to the superconducting state in constant magnetic field up to 12 T. The cause of the appearance of low- temperature “tails” (paracoherent transitions) on the resistive transitions, corresponding to different phase regimes of the vortex matter state is discussed. At temperatures higher than the critical temperature (T > \(T_\mathrm{c})\), the temperature dependence of the excess paraconductivity can be described within the Aslamazov–Larkin theoretical model of the fluctuation conductivity for layered superconductors.     

Effect of annealing treatment on optical properties and microstructural variation of $$\hbox {WO}_{3}/\hbox {Ag}/\hbox {WO}_{3}$$ multilayer nano-films

Structural and optical properties of \(\text {WO}_{3}/\text {Ag}/\text {WO}_{3}\) nano-multilayer composites were investigated for heat mirror applications. \(\text {WO}_{3}/\text {Ag}/\text {WO}_{3}\) thin films were fabricated through a physical vapour deposition method by using electron-beam evaporation at the vacuum chamber at 10\(^{-5}\) Torr. \(\text {WO}_{3}\) nano-layer was fabricated at 40 nm. Annealing treatment was carried out at 100, 200, 300 and 400\(^{\circ }\)C for 1 h after the deposition of first layer of \(\text {WO}_{3}\) on the glass. On \(\text {WO}_{3}\) film, Ag nano-layers with 10, 12 or 14 nm thickness were deposited. Individual layers morphology was investigated using atomic force microscopy (AFM) and deduced that a smoother layer can be achieved after the annealing at 300\(^{\circ }\)C. Ellipsometry analysis was executed to determine both layers, Ag film thickness and inter-diffusion between the \(\text {WO}_{3}\)–Ag–\(\text {WO}_{3}\) layers. It was inferred that there was almost no interfering among the \(\text {WO}_{3}\)–\(\text {WO}_{3 }\) layers in the samples with 12 and 14 nm Ag thickness; while silver was deposited on the annealed \(\text {WO}_{3}\) layer at 300\(^{\circ }\)C. UV–visible spectrophotometer showed that the annealing treatment of the first \(\text {WO}_{3}\) layer enhanced the transparency of films in the visible region. The innovations of the present study have been based on the annealing of the films and finding an optimum thickness for the Ag film at 12–14 nm. Heat mirrors efficiency was assessed according to the principle of their optical behaviour and optimum performance obtained for 14 nm of Ag film, deposited on annealed tungsten oxide at 300\(^{\circ }\)C.     

Characterization and optical properties of $$\hbox {Pr}_{2}\hbox {O}_{3}$$-doped molybdenum lead-borate glasses

\(\hbox {Pr}^{3+}\) doped molybdenum lead-borate glasses with the chemical composition 75PbO?[25–(x \(+\) y)\(\hbox {B}_{2}\hbox {O}_{3}]\)–\(y\hbox {MoO}_{3}\)–\(x\hbox {Pr}_{2}\hbox {O}_{3}\) (where \(x = 0.5\) and 1.0 mol% and \(y = 0\) and 5 mol%) were prepared by conventional melt-quenching technique. Thermal, optical and structural analyses are carried out using DSC, UV and FTIR spectra. The physical parameters, like glass transition \((T_{\mathrm{g}})\), stability factor \((\Delta T)\), optical energy band gap \((E_{\mathrm{gopt}})\), of these glasses have been determined as a function of dopant concentration. The \({T}_{\mathrm{g}}\) and optical energy gaps of these glasses were found to be in the range of 290–350\({^{\circ }}\hbox {C}\) and 2.45–2.7 eV, respectively. Stability of the glass doped with \(\hbox {Pr}^{3+}\) is found to be moderate (\(\sim \)40). The results are discussed using the structural model of Mo–lead-borate glass.     

Distribution of relaxation times investigation of $$\hbox {Co}^{3+}$$ doping lithium-rich cathode material $$\hbox {Li}[\hbox {Li}_{0.2} \hbox {Ni}_{0.1} \hbox {Mn}_{0.5} \hbox {Co}_{0.2}]\hbox {O}_{2}$$Li[Li0.2Ni0.1Mn0.5Co0.2]O2

The element \(\hbox {Co}^{3+}\) was introduced into lithium-rich material \(0.5\hbox {Li}_{2}\hbox {MnO}_{3} \cdot 0.5 \hbox {LiNi}_{0.5}\hbox {Mn}_{0.5}\hbox {O}_{2}\) by a polyacrylamide-assisted sol–gel method to form \(\hbox {Li}[\hbox {Li}_{0.2} \hbox {Ni}_{0.1} \hbox {Mn}_{0.5} \hbox {Co}_{0.2}]\hbox {O}_{2}\) and better electro-chemical performances were observed. Electrochemical impedance spectroscopy spectra were measured on 11 specific open circuit voltage levels on the initial charge profile. Then they were converted to the distribution of relaxation times (DRTs) g(\(\tau \)) by self-consistent Tikhonov regularization method. The obtained DRTs offered a higher resolution in the frequency domain and provided the number and the physical origins of loss processes clearly. Through the analysis of DRTs, the rapid augmentation of resistance to electronic conduction and charge transfer within the voltage range 4.46–4.7 V where the removal of \(\hbox {Li}_{2}\hbox {O}\) from \(\hbox {Li}_{2} \hbox {MnO}_{3}\) component took place was the most remarkable phenomenon and the \(\hbox {Co}^{3+}\) doping greatly reduced the resistance to electronic conduction Re. This gave us more evidence about the complicated ‘structurally integrated’ composite character of the material.     

Microwave-hydrothermal synthesis of mesoporous $$\upgamma $$-$$\hbox {Al}_{2}\hbox {O}_{3}$$Al2O3 and its impregnation with AgNPs for excellent catalytic oxidation of CO

Mesoporous \(\upgamma \)-alumina was synthesized by the microwave-hydrothermal process with a shorter duration time at 150\({^{\circ }}\)C/2 h followed by calcination at 550\({^{\circ }}\)C/1 h. Ag nanoparticles (AgNPs) were impregnated into \(\upgamma \)-alumina under a reducing atmosphere at 450\({^{\circ }}\)C. The synthesized product was characterized by X-ray diffraction (XRD), thermogravimetric (TG)/differential thermal analysis (DTA), X-ray photoelectron spectroscopy (XPS), \(\hbox {N}_{2}\) adsorption–desorption study, field-emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The BET surface area values of \(\upgamma \)-alumina and Ag-impregnated \(\upgamma \)-alumina were found to be 258 and 230 m\(^{2}\) g\(^{-1}\), respectively. FESEM images showed the formation of grain-like particles of 50–70 nm in size with a flake-like microstructure. The XRD, XPS and TEM studies confirmed the presence of Ag in the synthesized product. Catalytic properties of the product for CO oxidation was studied with the \(T_{50}\) (50% conversion) and \(T_{100}\) (100% conversion) values of 118 and 135\({^{\circ }}\)C, respectively; the enhanced values were compared with the literature reported values.     

$$\hbox {SiO}_{2}\hbox {/TiO}_{2}$$ multi-layered thin films with self-cleaning and enhanced optical properties

Self-cleaning, high transmittance glazing was obtained by cold spray deposition for glazings. The thin films contain \(\hbox {TiO}_{2}\), \(\hbox {SiO}_{2}\) and Au nanoparticles in different structures which allow for tailoring the optical, hydrophilic and photocatalytic properties. The crystallinity, morphology and surface energy were correlated with the optical transmittance and reflectance; the transmittance increased from 89.45 (for the glass substrate) to 91.76% when Au nanoparticles were used in the tandem layered structures. The samples containing alternating multi-layered \(\hbox {SiO}_{2}\) and \(\hbox {TiO}_{2}\) thin films without gold nanoparticles show hydrophilic surface; for these layers, the photocatalytic efficiency reaches 40% under simulated solar radiation. A conditioning effect based on adsorption was observed to increase the photocatalytic efficiency. These highly transparent coatings are well suited for glazings and fenestration, showing the self-cleaning effect based on combined superhydrophilicity and photocatalysis.     

Ga doping induced structural and optical modification in $$\hbox {Ge}_{2}\hbox {Sb}_{2}\hbox {Te}_{5}$$ Ge 2 Sb 2 Te 5 thin films

\(\text {Ge}_2\text {Sb}_2\text {Te}_5\) (GST) is considered a promising candidate for next-generation data storage devices due to its unique property of non-volatility and low power consumption. In present work, the bulk alloys and thin films of (\(\text {Ge}_2\text {Sb}_2\text {Te}_5\))\(_{100-x}\text {Ga}_x\) (x = 0, 3, and 10) are prepared using melt quenching and thermal deposition method, respectively. The effect of Ga doping on host composition is investigated by analyzing X-ray diffraction patterns and field emission scanning electron microscope images. From obtained results, it is found that all doped thin films retained the amorphous nature and exhibited uniform and smooth morphology. In Raman spectra, the appearance of a new peak in 10% Ga-doped GST thin film indicated an alteration in the atomic arrangement of host lattice. Transmission spectra revealed the highly transparent nature of all deposited thin films in the near-infrared region. The optical band gap of Ga-doped GST thin film is lower than that of the pure GST thin film which can be correlated with an increase in band tailing, attributed to an increase in localized defect states in the band gap. Due to the pronounced electronegativity difference between the Ga and Te element, new Ga–Te bonds with a higher number of wrong bonds (Ge–Ge, Sb–Sb, and Ge–Sb) are expected to thermally stabilize the amorphous phase. Such results predict the better performance of Ga-doped GST composition for better performance of phase-change random access memory.

     

Exfoliated $$\hbox {WS}_{2}$$ nanosheets: optical,photocatalytic and nitrogen-adsorption/desorption characteristics

In this work, we report on structural, optical, photocatalytic and nitrogen adsorption–desorption characteristics of \(\hbox {WS}_{2 }\) nanosheets developed via a hydrothermal route. X-ray diffraction (XRD) studies have revealed a hexagonal crystal structure, whereas nanodimensional sheets are apparently observed in scanning and transmission electron microscopy (SEM and TEM) micrographs. As compared to the bulk counterpart, the \(\hbox {WS}_{2}\) nanosheets exhibited a clear blue shift. Through Brunauer–Emmett–Teller (BET) surface area analysis, average surface area, pore volume and pore size of the NSs were calculated as 211.5 \(\hbox {m}^{2}~\hbox {g}^{-1}\), 0.433 cc \(\hbox {g}^{-1}\) and 3.8 nm, respectively. The photocatalytic activity of the \(\hbox {WS}_{2}\) nanosheets was also examined with malachite green (MG) as the target dye under both UV and day light (visible) illumination conditions. Accordingly, a degradation efficiency as high as 67.4 and 86.6% were witnessed for an irradiation time duration of 60 min. The nano-\(\hbox {WS}_{2}\) systems have immense potential in optoelectronics, solid-lubrication and other next generation elements.     

Fabrication and enhanced photoluminescence properties of $$\hbox {NaLa}(\hbox {MoO}_{4})_{2}$$: $$\hbox {Sm}^{3+}$$Sm3+, $$\hbox {Bi}^{3+}$$Bi3+ phosphors with high efficiency white-light-emitting

The tetragonal scheelite-type \(\hbox {Sm}^{3+}\hbox {/Bi}^{3+}\) ions co-doped with \(\hbox {NaLa}(\hbox {MoO}_{4})_{2}\) phosphors were synthesized by a facile sol–gel and combustion process using citric acid as complexing agent. The crystal structure and morphology of these as-prepared samples were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Furthermore, UV-absorption and the photoluminescence (PL) properties of these phosphors were systematically investigated and the PL of the phosphors shows strong white light emissions. Efficient energy transfer from the \(\hbox {MoO}_{4}^{2-}\) group or \(\hbox {Bi}^{3+}\) ions to \(\hbox {Sm}^{3+}\) ions was established by PL investigation excited at 405 nm. The PL intensity of the studied materials was investigated as a function of different \(\hbox {Sm}^{3+}\) and \(\hbox {Bi}^{3+}\) concentrations. The PL investigations revealed that the phosphors exhibit apparent characteristic emissions, which is ascribed to the transition from the ground state energy level \(^{4}\hbox {G}_{5/2}\) to excited state energy levels \(^{6}\hbox {H}_{\mathrm{J}}\) (\(J= 5/2, 7/2, 9/2\)) and the \(\hbox {NaLa}(\hbox {MoO}_{4})_{2}\): 4 mol% \(\hbox {Sm}^{3+}\) and \(\hbox {NaLa}(\hbox {MoO}_{4})_{2}\): 4 mol% \(\hbox {Sm}^{3+}\), 8 mol% \(\hbox {Bi}^{3+}\) present white emissions with the CIE coordinates of (0.350, 0.285) and (0.285, 0.229), respectively. The absolute quantum efficiencies of the phosphors are 40% (\(\hbox {NaLa}(\hbox {MoO}_{4})_{2}\): 4 mol% \(\hbox {Sm}^{3+}\)) and 52% (\(\hbox {NaLa}(\hbox {MoO}_{4})_{2}\): 4 mol% \(\hbox {Sm}^{3+}\), 8 mol% \(\hbox {Bi}^{3+}\)), respectively.     

Synthesis and up-conversion emissions of $$\hbox {Yb}^{3+}{/}\hbox {Er}^{3+}$$, $$\hbox {Yb}^{3+}{/}\hbox {Tm}^{3+}$$Yb3+/Tm3+ and $$\hbox {Yb}^{3+}{/}\hbox {Tm}^{3+}{/}\hbox {Gd}^{3+}$$Yb3+/Tm3+/Gd3+ co-doped $$\hbox {KLu}_{2}\hbox {F}_{7}$$KLu2F7

\(\hbox {Yb}^{3+}/\hbox {Er}^{3+}\), \(\hbox {Yb}^{3+}/\hbox {Tm}^{3+}\), or \(\hbox {Yb}^{3+}/\hbox {Tm}^{3+}/\hbox {Gd}^{3+}\) co-doped \(\hbox {KLu}_{2}\hbox {F}_{7}\) up-conversion (UC) materials were synthesized through a hydrothermal method or an additive-assisted hydrothermal method. The X-ray diffraction (XRD) results suggested that the materials crystallized in orthorhombic phase, yet, the potassium citrate (CitK) introduction affected immensely the crystalline purity of final material. The field emission scanning electron microscopy (FE-SEM) results suggested that the additive adding had effects on size and morphology of the material, which affected the UC emissions further. Green/red UC emissions of \(\hbox {Er}^{3+}\), UV/blue/IR UC emissions of \(\hbox {Tm}^{3+}\), and UV UC emissions of \(\hbox {Gd}^{3+}\) were observed in the orthorhombic phase of \(\hbox {KLu}_{2}\hbox {F}_{7}\) materials. The excitation power-dependent UC emissions illustrated that the UC emission intensity initially increased, then decreased with the increase in excitation power. At the same time, the variation rates of different transitions in \(\hbox {Er}^{3+}\) or \(\hbox {Tm}^{3+}\) are also different. In addition, the \(\hbox {Er}^{3+}\) or \(\hbox {Tm}^{3+}\) concentration-dependent UC emission results suggested that the optimal doping concentration of \(\hbox {Er}^{3+}\) is 2 mol% and \(\hbox {Tm}^{3+}\) is 0.5 mol% with the \(\hbox {Yb}^{3+}\) concentration fixed as 20 mol%. The experimental results suggest that the orthorhombic phase of \(\hbox {KLu}_{2}\hbox {F}_{7}\) should be a good host lattice for UC emitters.     

Microwave hydrothermal synthesis and upconversion luminescence properties of $$\hbox {Yb}^{3+}$$/$$\hbox {Tm}^{3+}$$Tm3+ co-doped $$\hbox {NaY}(\hbox {MoO}_{4})_{2}$$NaY(MoO4)2 phosphor

Tetragonal \(\text {NaY}(\text {MoO}_{4})_{2}\) (NYM) phosphors co-doped with \(\hbox {Yb}^{3+}\) and \(\hbox {Tm}^{3+}\) ions were synthesized through microwave hydrothermal method followed by calcining treatment. Powder X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and photoluminescence spectra were used to characterize the properties of as-prepared samples. The results show that \(\hbox {Yb}^{3+}\)/\(\hbox {Tm}^{3+}\) co-doped NYM displayed bright blue emission near 472 and 476 nm (\(^{1}\hbox {G}_{4}\rightarrow {}^{3}\hbox {H}_{6}\) transition), strong near-infrared upconversion (UC) emission around 795 nm (\(^{3}\hbox {H}_{4}\rightarrow {}^{3}\hbox {H}_{6}\) transition). The optimum doping concentrations of \(\hbox {Yb}^{3+}\) and \(\hbox {Tm}^{3+}\) for the most intense UC luminescence were obtained, and the related UC mechanism of \(\hbox {Yb}^{3+}\)/\(\hbox {Tm}^{3+}\) co-doped NYM depending on pump power was studied in detail.     

Effect of annealing temperature and $$\hbox {CdCl}_{2}$$ treatment on the photo-conversion efficiency of $$\hbox {CdTe/Zn}_{0.1}$$CdTe/Zn0.1$$\hbox {Cd}_{0.9}$$Cd0.9S thin film solar cells

We report the effects of annealing in conjunction with \(\hbox {CdCl}_{2}\) treatment on the photovoltaic properties of \(\hbox {CdTe/Zn}_{0.1}\hbox {Cd}_{0.9}\)S thin film solar cells. CdTe layer is subjected to dry \(\hbox {CdCl}_{2}\) treatment by thermal evaporation method and subsequently, heat treated in air using a tube furnace from 400 to \(500{^{\circ }}\hbox {C}\). AFM and XRD results show improved grain size and crystallographic properties of the CdTe film with dry \(\hbox {CdCl}_{2}\) treatment. This recrystallization and grain growth of the CdTe layer upon \(\hbox {CdCl}_{2}\) treatment translates into improved photo-conversion efficiencies of \(\hbox {CdTe/Zn}_{0.1}\hbox {Cd}_{0.9}\)S cell. The results of dry \(\hbox {CdCl}_{2}\) treatment were compared with conventional wet \(\hbox {CdCl}_{2}\) treatment. Photo-conversion efficiency of 5.2% is achieved for dry \(\hbox {CdCl}_{2}\)-treated cells in comparison with 2.4% of wet-treated cell at heat treatment temperature of \(425{^{\circ }}\hbox {C}\).     

Application of Non-Isothermal Thermogravimetric Method to Interpret the Decomposition Kinetics of \hbox {NaNO}_{3}, \hbox {KNO}_{3}, and \hbox {KClO}_{4}

The non-isothermal thermogravimetric method was used to study the thermal decomposition of \(\hbox {KClO}_{4}, \hbox {KNO}_{3}\) , and \(\hbox {NaNO}_{3}\) at heating rates of (5, 10, 15, and 20)  \(\hbox {K}\cdot \hbox {min}^{-1}\) . The activation energy of thermal decomposition reactions was computed by isoconversional methods of Ozawa–Flynn–Wall, Kissinger–Akahiro–Sunose, and Friedman equations. Also, the kinetic triplet of the thermal decomposition of salts was determined by the model-fitting method of the modified Coats–Redfern equation. The activation energies of \(\hbox {KClO}_{4}, \hbox {KNO}_{3}\) , and \(\hbox {NaNO}_{3}\) of (293 to 307, 160 to 209, and 192 to 245)  \(\hbox {kJ}\cdot \hbox {mol}^{-1}\) , respectively, are obtained by non–isothermal isoconversional methods. The modified Coats and Redfern method showed that the most probable mechanism functions \(g(\alpha )\) of \([-\hbox {ln}(1 - \alpha )]^{1/3}\) (model A3: Arami–Erofeev equation) and \((1 - \alpha )^{-1}- 1\) (model F2: second order) can be used to predict the decomposition mechanisms of \(\hbox {KClO}_{4}\) , \(\hbox {KNO}_{3}\) , and \(\hbox {NaNO}_{3}\) , respectively.