Non-vacuum Process Research Articles

Defect analysis of the Cu-Cr-Zr-Nb alloys prepared by the non-vacuum melting process

The microstructure and properties of the Cu-Cr-Zr-Nb alloys prepared by non-vacuum melting and vacuum melting were compared and analyzed in this paper. The results showed that, compared with vacuum melting, the alloy prepared by non-vacuum melting had a more uneven microstructure and a coarser grain. In the meantime, the alloy prepared by non-vacuum melting stored less energy and had a lower proportion of HAGBs (high-angle grain boundaries), and the texture distribution along the TD and RD directions was not uniform. In terms of properties, the hardness and electrical conductivity of the Cu-Cr-Zr-Nb alloys prepared by non-vacuum melting were lower than those of the alloys prepared by vacuum melting. The electrical conductivity of the non-vacuum melting alloy was only 70.8 %IACS (International Annealed Copper Standard), and the average hardness fluctuated greatly. However, the electrical conductivity of the alloy prepared by vacuum melting could reach 81.0 %IACS, and the hardness was very uniform. Further research indicated that there were cracks and inclusions in the alloy prepared by non-vacuum melting. A large number of ZrO2 inclusions were found along the grain boundary, which demonstrated that the oxide inclusion was the primary cause of the crack formation. On this basis, three important suggestions for the preparation of the Cu-Cr-Zr-Nb alloys by non-vacuum melting were put forward to reduce the cost and improve the properties of the alloys. It provided guidance for developing high-performance Cu-Cr-Zr-Nb alloys by non-vacuum melting.

High-Performance Solid Oxide Electrochemical Cells with Ultrathin and Dense Double-Doped Ceria Interlayers

To mitigate the drastic global climate change, which mainly originated from the indiscriminate use of fossil fuels, various alternative eco-friendly energy conversion technologies have been studied. Among them, solid oxide electrochemical cells (SOCs) are one of the most promising devices with superior power and energy densities and low environmental impact. The current main objective of the SOCs research field is lowering the operating temperature to secure thermal cycling stability and minimize system costs. To achieve a feasible performance for commercial usage at reduced temperatures, it is inevitable to use state-of-the-art cobalt-based oxygen electrode materials. However, cobalt-based materials inherently react with conventional zirconia-based electrolytes at high temperatures forming insulating phases at the interface. Thus, the ceria interlayer is essentially required to prevent unwanted chemical reactions. In this study, we newly developed thin and dense doubly doped ceria interlayers (~250 nm) using a non-vacuum solution deposition process with gelatin. The SOCs with the thin-film ceria interlayers achieved superior electrochemical performance both in the fuel cell (FC) and the electrolysis cell (EC) mode (~3.5W/cm2 and ~2.1A/cm2 at 750°C for the FC and EC modes, respectively) compared to the SOC with a conventional porous and thick interlayer. The mechanistic analyses showed that the thin-film interlayer provides a much shorter route for oxygen ionic conduction and more active sites for oxygen reduction reaction (ORR) and oxygen evolution reaction (ORR) at the interface compared to the porous interlayer. Our results suggest that the thin-film doubly-doped ceria interlayer fabricated using the gelatin-assisted process has a high potential for development of high-performance SOCs.

Lead-free ferroelectric BaTİO3 (BTO) thin films produced by the green process

In this study, we present structural and dielectric properties of doped and un-doped BaTiO3 (BTO) thin films samples. BTO sample were produced by non-vacuum process specifically sol-gel spin coating technique. The doped samples involve Co, Gd, Mn, Sr, and Zr in the Ba-site of the BTO. We used SEM, XRD and AFM analysis techniques to characterized our samples. We also conduct a dielectric measurement using a Vector Network Analyzer. According to our findings the highest dielectric constants were observed for Sr and Zr doped BaTiO3 thin films which were not applied any heat treatment and were obtained as 9.25 and 9.4 ​at 5.4 ​GHz frequency, respectively. On the other hand, the value of dielectric constants of the films that were analyzed after heat treatment were determined as 7.7 and 7.45 ​at 6.8 ​GHz on Sr and Zr doped BaTiO3 thin films, respectively.

High-Performance Solid Oxide Electrochemical Cells with Ultrathin and Dense Double-Doped Ceria Interlayers

In this study, we utilized a La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF)-GDC composite oxygen electrode on a thin and dense doubly doped ceria interlayer for a high-performance solid oxide electrochemical cell (SOC). The ceria interlayers were generated via a non-vacuum solution deposition process with gelatin. The SOC achieved a high maximum power density (MPD) of 2.46 W/cm2 at 750oC along with stable operation for 30 hours in the fuel cell (FC) mode. Our results suggest that the integration of the LSCF-GDC composite and the dense ceria interlayer holds a significant promise for development of high-performance SOCs.

Synthesis and fabrication of superstrate and substrate Cu2ZnSnS4/CdS thin film solar cells utilizing copper powder as local materials

Cu2ZnSnS4 is a promising material for low-cost thin-film solar cells. This paper reports a new approach to fabricating a solar cell using a Superstrate and Substrate configuration. We utilized a non-vacuum deposition process to deposit Copper Zinc Tin Sulfate (CZTS) and Cadmium Sulphate (CdS) on a glass substrate. To achieve this, we adopted the sol-gel spin coating method for CZTS and the Chemical Bath Deposition (CBD) method for the CdS layer. The solar cell has two structures: ITO/Cu2ZnSnS4/CdS/Ag for substrate configuration and ITO/CdS/Cu2ZnSnS4/Ag for superstrate configuration. The Cu/(Zn+Sn) atomic ratio was set to 0.86, while Zn/Sn was set to 1.25. Our CZTS/CdS solar cell achieved a 48.7 × 10-6 % power conversion efficiency with a 1.40 eV band gap and 98.71 % external quantum efficiency at 373 nm for the superstrate configuration. For the substrate configuration, the power conversion efficiency was 19.0 × 10-6 % with a 1.49 eV bandgap and 95.74 % external quantum efficiency at 321 nm. Based on the results presented in the text, the CZTS solar cell with a superstrate configuration achieved a higher power conversion efficiency and external quantum efficiency than the substrate configuration. The superstrate configuration allowed for better light absorption in the CZTS layer and reduced the reflection of light back into the substrate. This configuration also prevented the back diffusion of CdS into CZTS and improved the electrical performance of the solar cell. Therefore, the superstrate configuration is more efficient than the substrate configuration for CZTS solar cells.

Development of n-type Zn(O, S) buffer layer deposited by open-air CVD method for Cu(In, Ga)Se2 solar cells

A Zn(O, S) thin-film is deposited utilizing an open-air CVD method by evaporating zinc-diethyldithiocarbamate, which is a non-vacuum and dry process. In an X-ray diffraction measurement, it is revealed that the films have a wurtzite structure and an [O]/([O] + [S]) ratio of 10%. A bandgap energy of 3.1 eV is estimated from the transmittance and reflectance spectra. By applying the Zn(O, S) as an n-type buffer layer, Cu(In, Ga)Se2 solar cells are fabricated. In the current density–voltage characteristics, distortion is observed at the bias voltages above the open-circuit voltage. It is implied that a large conduction band offset exists at a Zn(O, S)/CIGS interface. A quantum efficiency spectrum in the wavelength region of 380–512 nm is improved compared to a traditional CdS buffer layer. Finally, a 9.2%-efficient CIGS solar cell is demonstrated utilizing the Zn(O, S) buffer layer through an all-dry process.

Fabrication of Cu2ZnSnS4 (CZTS) by co-electrodeposition of Cu-Zn-Sn alloys, and effect of chemical composition of CZTS on their photoelectrochemical water splitting

Sulfide kesterite Cu2ZnSnS4 (CZTS), an intrinsic p-type semiconductor, provides an attractive low-cost, environmentally friendly photoelectrochemical (PEC) water splitting to evolve hydrogen. The purpose of this study was to clarify the effect of the chemical composition of CZTS on the PEC properties and the correlation with their structures. The CZTS was fabricated on a Mo/glass by a non-vacuum process, i.e., co-electrodeposition (co-ED) of Cu-Zn-Sn (CZT) alloys, followed by sulfurization with solid sulfur. To optimize the chemical composition of CZTS, the bath concentrations, applied potentials and amounts of electric charge for preparation conditions of the CZT precursors were examined. The CZTS with Cu-poor and Sn-rich composition compared with stoichiometry was found to exhibit relatively effective PEC water splitting. It was suggested that the high PEC performance was attributed to efficient charge carrier transport due to the presence of a small amount of SnO2 phase on the CZTS surface.

Effect of molybdenum on structure and properties of surface layers of steel 12Kh18N9T

The results of hardening the surface of chromium-nickel steel 12Kh18N9Т by the method of non-vacuum electron-beam processing are presented in this research paper. As a result, a molybdenum-containing layer with 2 mm thickness was formed. The creation of surface layers of this composition allow to increase microhardness by 2.25 times, wear resistance by 1.7 times in comparison with unhardened steel.

Electrodeposition of Ni-Fe Alloy in Presence of Complexing Agent

The nickel-iron alloys have been widely used for versatile soft magnetic applications and electro-magnetic applications due to their magnetic properties for a long time. Also, it has been discovered that Ni-Fe alloy near 36 wt% Ni shows almost zero thermal expansion composition(CTE) in a wide temperature range (~150 ℃). The phenomenon showing low CTE in a specific composition is called the Invar effect. Due to the Invar effect, Invar alloys are used for temperature-sensitive applications such as oscillators and fiber-optic package parts. Invar alloy films are used for fine metal masks, an essential part of OLED fabrication. The invar film currently in use is fabricated using the pyrometallurgy method, more than 20um thick. However, miniaturization and high performance of the products require the thinner thickness of the Invar film, around 10um thick which shows the need for a bottom-up fabrication process of invar film. There are various methodologies to fabricate thin films, such as thermal evaporation, sputtering, CVD, and electrodeposition. Most fabricating processes are the vacuum process, a high-cost and non-continuous process. On the other hand, electrodeposition is a non-vacuum process, relatively low-cost, large-scale, and continuous process.Despite these advantages, there are some obstacles to gaining the Invar thin film by electrodeposition, such as anomalous deposition, composition uniformity, and higher CTE of electrodeposited Invar film. There are researches[1-3] about electrodeposited Ni-Fe thin films in the aspect of CTE, magnetic properties, crystal structures, etc. However, very few researchers have seen the effect of complexing agents other than specific complexing agents such as boric acid and ascorbic acid. In addition, Ni-Fe electrodeposition shows very different results depending on temperature and agitation, but no research confirms the effect on various complexing agents under the same condition.In this study, we synthesized Ni-Fe alloy thin film by electrodeposition in the presence of various complexing agents with different functional groups (amine, carboxyl, alcohol, etc.) such as glycolic acid, malonic acid, ethylenediamine, etc. on 20um stainless 304 foil substrates. The electrodeposition was conducted under the aqueous acidic bath(pH 2) at 55℃. Electrochemical studies were conducted to set appropriate potential and current density for electrodeposition. The thin film was characterized by SEM, EDS, XRD, and copper strip tests to observe the difference in composition, surface morphology, phase, and internal stress.

Effects of Vacuum-Stirring Purification Process on Al-6Mg Alloy Melt

Aiming for hydrogen and oxidation easily produced in the melting process of Al-Mg alloys, three processes, including non-vacuum static melt treatment, non-vacuum rotary-injection purification and vacuum-stirring purification, were used to purify the Al-6Mg alloy melt. The hydrogen content and inclusion content were studied by means of the solid-state hydrogen measurement method, reduced pressure test method, FESEM and EDS. The results show that the purification effect of vacuum-stirring purification is better than that of the non-vacuum static melt treatment and non-vacuum rotary-injection purification. The hydrogen content of the melt decreases from 0.48 mL/100 gAl in the non-vacuum static treatment, to 0.32 mL/100 gAl in the non-vacuum rotary-injection purification process and to 0.10 mL/100 gAl in the vacuum-stirring purification process. The inclusion content of the melt decreases from 2.6% in the non-vacuum static treatment to 0.69% in the non-vacuum rotary-injection purification process, and to 0.39%, in the vacuum-stirring purification process.

Bonding mechanism and preparation process of titanium/iron composite thin sheet by non-vacuum rolling

As a new type of layered metal composite sheet, titanium/iron composite thin sheet has attracted much attention because it can meet the dual requirements of the environment and material properties. This paper reports a non-vacuum rolling method that is more suitable for preparing titanium/iron composite thin sheet in industrial production. Herein, the bonding mechanism of the layered metal composite sheet was elucidated by analyzing the forces on the sheets during the non-vacuum rolling process then it was applied to explain the influence mechanism of the rolling reduction rate on interfacial bonding properties. The titanium/iron composite thin sheet was prepared by non-vacuum rolling with a 65% rolling reduction rate, and the interfacial microstructure was studied to verify the accuracy of theoretical judgments. The results show that a shear deformation zone exists at the interface of the layered metal composite sheet in the rolling process. In this zone, the oxide film on the interface breaks, and the exposed fresh metal undergoes metallurgical bonding under the action of radial rolling force to form a composite interface. With the increase of rolling reduction rate, the range of the shear deformation zone expands, and the radial rolling force acting on the interface increase, which is the main reason for the improvement of the rolling reduction rate on the bonding effect. Shear deformation caused vast dislocations in the interface microstructure of composite sheet. The texture of the titanium layer has a certain width under the action of shear deformation. The texture of the iron layer is mainly α-fiber, caused by shear deformation. Moreover, broken oxide films and diffusion layers of titanium and iron elements were observed at the interface.

A simple method for Ge incorporation to enhance performance of low temperature and non-vacuum based CZTSSe solar cells

Despite the slow efficiency development, Cu2ZnSn(S,Se)4 still is a promising absorber material for solar cells for its easy and low cost way of fabrication and the abundance of its elements. Similarly, also CdTe faced a long period when the record efficiency would not improve over 16.5% until a different paradigm was introduced. CZTSSe, compared to other absorbers, has the advantage that can be successfully made by solution-based growth techniques which are unique for their low cost. However this is meaningful only if selenization process is not done at high temperatures and without complicated processes. So we have optimized an easy, low cost, non-vacuum fabrication process for Cu2(Zn,Sn)(S,Se)4 thin-film absorber layers by spin coating of precursor and subsequent lower temperature selenization. A precursor solution is deposited on a Mo coated glass and the stack is then annealed below 450 °C in Se atmosphere and without the application of toxic hydrazine. With this process, we have already presented efficiencies of around 5.5%, but in this work, we introduce a simple impurity inclusion process by treating the surface of the precursor film with chlorine-based compound containing either Na, K or Ge. This allows to improve the open circuit voltage and the current density, with an increase in efficiency of 25% compared to the non-treated sample. The structural modifications are addressed by X-ray diffraction, Raman spectroscopy, atomic force microscopy and scanning electron microscopy. Current-voltage, capacitance-voltage and drive level capacitance profiling are used to analyse performance and defect density in the finished devices.

Tuning of photosensitivity and optical parameters of ZnO based photodetectors by co-Sn and Ti doping

In this study it was shown that co-doping of zinc oxide (ZnO) thin films with tin (Sn) and titanium (Ti), can significantly increase photosensitivity of metal-semiconductor-metal (MSM) type ZnO based photodetectors. Doping of ZnO thin films was carried out by non-vacuum sol-gel process. The 0.5% Sn and 1% Ti doped thin films show highest photosensitivity under 365 nm light illumination. The photosensitivity increased from 42 to 1552 with the addition of Sn and Ti. Furthermore, the decay time of pristine (undoped) photodetector decreased from 31.2 s to 5.4 s by tuning doping concentration to 1% Sn and 1% Ti. These results indicate that co-doping of ZnO thin films with Ti and Sn can enhance on/off current ratio and decay time parameter of the photodetector. Furthermore, the absorption coefficient, optical conductivity refractive index, skin depth, extinction coefficient and dielectric constants of samples strongly change with doping of ZnO thin films, which can be useful for optoelectronic applications.

Ink - based non-vacuum process of synthesis of multicomponent Cu2ZnSn (Se1-x,Sx)4 for use in low-cost photovoltaic absorbers

In this present work, Cu2ZnSn(Se1-x,Sx)4 nanocrystals with tunable band gaps have been synthesized via hot injection method in conjunction with TOP/TOP capping ligands. By varying the input precursor ratio Se/( S + Se), by adjusting the composition parameter x from 0 to 1.0, the band gaps of the CZTSSe-based nanocrystals can be linearly tuned from 1.2 to 1.5 eV respectively. For CZTSSe-based nanocrystals, high intensity of XRD peak corresponding to (112) direction revealed that the growth is oriented along (112) direction and its intensity increases with increase in Se/(S + Se) input precursor ratio. As the Se-content increases, the larger Se atoms (1.98 Å) replace the smaller larger S atoms (1.84 Å) resulting in an increase in the lattice parameters as shown by the shift of the XRD peaks to lower values of 2θ.XRD studies reveal the presence of stable kesterite phase although the presence of either stannite phase or both cannot be ruled out completely. It has been found that CZTSSe nanocrystallites owing to its high crystallinity and well-ordered 3-dimensional network and hence controlled morphology in its pristine form as compared with CZTSe, CZTS counterparts exhibits higher homogeneity, resistance against agglomeration and eventually higher current-voltage characteristics. To, the best of our knowledge, this is the first detailed report on the synthesis of multicomponent Cu2ZnSn(Se1-x,Sx)4 nanocrystals by hot injection method via the usage of both TOP (trioctyl phosphine) & TOPO (trioctyl phosphine oxide) capping ligands. The primary technological advantage of creating nanocrystals by this solution based method is the capability to easily form an ink that is compatible with a large variety of scalable film formation or printing processes for photovoltaic applications. Copyright © 2016 VBRI Press.

Amorphous CdO-In2O3 alloy thin films with high conductivity and transparency synthesized by sol-gel method

The growth of CdO-In2O3 amorphous oxide semiconductor alloys with high mobility in a wide composition range, suitable for many optoelectronic applications, has been previously reported using room temperature sputtering. In the present work, we synthesized Cd1−xInxO1+δ alloy thin films across the entire composition range using the non-vacuum, low-cost sol-gel spin coating method. Structural, electrical and optical properties of these alloy films were studied using a variety of analytical tools. We find that the alloy films become amorphous within the In composition range of 0.2 <x < 0.7, while films with x < 0.2 and x > 0.7 have the rocksalt CdO and bixbyite In2O3 structure, respectively. As-grown amorphous alloys have resistivity in the ranging from high 10−3 to low 10−2 Ω-cm due to their relatively low mobility of<10 cm2/Vs. Electrical properties of these amorphous films are improved after annealing at ~400 °C with a mobility of ~10 cm2/Vs and a low resistivity in the low 10−3 Ω-cm range. The optical gap varies from 2.54 to 3.52 eV with increasing In mole fraction, so that transmittance> 85% over a wide transmission window of ~400–1600 nm can be achieved. The low temperature, low-cost non-vacuum processing, wide bandgap tunability, and low resistivity, make these sol-gel alloy films promising materials for optoelectronic applications, especially on organic layers and/or flexible substrates.

Investigation of Cu2ZnSnS4 film by Simple Flow-Coating Technique

This present study aims to investigate a Cu2ZnSnS4 (CZTS) film obtained by simple flow-coating technique using with CZTS precursor solution synthesized by non-vacuum sol-gel process and annealing without sulfurization. The precursor solution was prepared by mixture CuCl2, ZnCl2 SnCl2 and CH4N2S molar to obtain the ion of Cu, Zn, Sn and S. The CZTS film was investigated by using XRD, FE-SEM, and UV-Visible Spectroscopy, respectively. The XRD results show main peak at the angle 28.48° according with (112) plane on the kieserite phase of tetragonal structure, crystallite size average about ∽ 103.137 ± 0.9788 nm. The surface morphology was observing microscopic porosity structure of the particles and cross-section achieve a film thickness of approximately 32.92 ± 0.62 μm. The EDX result was revealed that whereas the composition nonuniformity from the simple flow-coating process. The optical properties show band gap energy quite close to the optimum value ∼ 1.518 eV, good optical absorption (∼105 cm−1). These characteristics make the simple fabrication CZTS film suitable material as an absorber layer in photovoltaic.

Research progress in laser direct writing of flexible circuit

<p indent="0mm">At present, the flexible electronics industry is in an important transitional period, and various flexible electronic devices with novel properties and enhanced functions are constantly emerging, from limited flexibility to flexible electronic devices with shape adaptability and ductility. This has greatly stimulated demand for flexible electronic devices. The development of manufacturing technologies for flexible circuits with smaller feature sizes and better performance on larger-format substrates at lower costs has attracted increasing attention. Among various technologies, laser direct writing has proven to be an efficient and flexible manufacturing method that can produce large-area flexible electronic circuits. As a nonlithographic, nonvacuum, and online processing technology, laser direct writing has received considerable attention. It can be employed in the production of circuit electrodes of various substrates, including heat-sensitive flexible substrates, and it has huge application prospects in the production of flexible electronic and energy storage devices, sensors, and wearable electronic devices. On this basis, this article summarizes the latest development in the laser direct writing of flexible circuit (LDWFC) technology for manufacturing flexible circuits. It focuses on the material types and characteristics of the conductive inks suitable for LDWFC in the production of flexible circuits. The LDWFC processing technology is introduced in detail from four aspects: laser sintering technology, laser reduction technology, laser-induced modification technology, and laser auxiliary circuit manufacturing technology. In addition, the application of LDWFC in flexible energy storage devices, tenderness sensors, and flexible displays is introduced, and the development prospects of LDWFC technology in flexible circuit manufacturing are highlighted.

Solution process manufacture of a simple, multifunctional flexible sensor based on capacitance measurement

Conventional sensors are rigid, involve complex processes and structures, and one sensor can detect only one type of stimulus. The manufacturing costs of such devices are high owing to the use of vacuum processes for the formation of thin films and electrodes and the complicated fabrication processes required to construct multiple layers. In addition, the multiple-layer design increases the risk of peeling due to mechanical movement. In this study, to solve the aforementioned problems, a simple two-layer multi-sensor has been fabricated using a non-vacuum solution process. The sensor consists of a light absorption layer comprising polyvinyl butyral and semiconductor particles and a top layer comprising two spiral-shaped Ag nanowire electrodes. The sensor experiences minimal damage by external adhesives and has a light-sensitive optical response at 420 nm and at 1.2 mW cm−2. Herein, the capacitance of the sensor applied to the two-electrode structure was determined, along with the light sensitivity and change in noise with frequency. We believe that the proposed multi-sensor can be applied in a wide range of fields because it can act as a touch sensor and light sensor.

Highly Stable Completely Non-Vacuum Process Multi-Porous-Electrodes-Layered Perovskite Solar Cell

Highly Stable Completely Non-Vacuum Process Multi-Porous-Electrodes-Layered Perovskite Solar Cell

Crystal structure and optical properties of non-vacuum solution-based processed Cu2ZnSnS4 (CZTS) thin-film

Cu2ZnSnS4 (CZTS) material has emerged as an attractive material for the absorber layer in solar cells application. CZTS has similar properties with its successful predecessor CIGS, but CZTS offers the advantage of low-cost constituents, material abundance, and nontoxicity. We fabricated CZTS thin-film using non-vacuum solution-based process and then the deposition process using the spin-coating technique in the present work. Afterward, we observed that the CZTS thin-film was successfully fabricated with kesterite structure crystal with an optical bandgap of 1.56 eV. We also confirmed that the CZTS thin-film exhibit a high light-harvesting efficiency at a low wavelength suitable for the solar cells application's absorber layer.