Vacuum Evaporation Research Articles

AUTOMATED CONTROL OFTHE THIN FILMS ELECTRICALCONDUCTIVITY BY THE EDDY CURRENT METHOD

The article considers the possibility of using the eddy current method of non-destructive testing for the problems of measuring the electrical conductivity of thin metal films. As the object of measurement, we used copper films of various thicknesses obtained by vacuum vapor deposition. A review of current trends in the use of copper films in modern industry and science is presented, and an analysis is made of current methods of non-destructive testing suitable for studying thin copper films. A brief description of the deposition method and the hardware-software complex for measuring the electrical conductivity of the film is presented. A calibration curve is presented, which makes it possible to restore the values of the electrical conductivity of the film from the value of the signal of the eddy current transducer. GaAs samples were selected to construct a calibration curve. The decision is explained by the proximity of the values of the electrical conductivity of this chemical compound to the calculated indicators of the obtained thin films. The results of testing films with different characteristics are presented and the distribution of the electrical conductivity of the films depending on the batch is shown. A series of practical measurements of thin films demonstrated the existence of a relationship between the mass of the initial substance that was subjected to deposition and the characteristics of the resulting films. According to different values of electrical conductivity within the same batch, it was concluded that there is a difference in the quality of deposition of different films.

Employing pre-annealing as a control tool for alloying in CdSeTe/CdTe stacks produced by evaporation in vacuum

Alloying plays a critical role in CdSeTe/CdTe stacks used as absorber structure in high efficiency solar cells. In this study, the effect of pre-annealing between CdSeTe and CdTe on the structural and optical properties of stacks was examined in detail. After the CdSeTe layers (before CdTe) were grown by vacuum evaporation, pre-annealing was applied at moderate temperatures in the range of 200°C–300 °C. According to both XRD patterns and Raman spectra, a clear effect of pre-annealing temperature on alloying ratios and phase formations between CdSeTe and CdTe was ascertained. It was observed from the surface images that the change in pre-annealing temperature affected the grain sizes and morphology, depending on the Se ratios in the alloying. It was found that the transmission spectrum shifted to the long wavelength region with the change in crystallization as a result of pre-annealing. In the PL spectra, the presence of transitions related to the phase structures revealed by the XRD results was detected. In consequence, pre-annealing at 250 °C presented more promising results for potential CdTe cell applications.

The phases formed in Sn/Co thin bilayer upon heating

The structure and phases formed in Sn/Co thin films are interesting both from the solid-state chemistry point of view and due to applications of such a metallic bilayer. The phases forming in thin films Sn/Co obtained by thermal vacuum evaporation on two different substrates SiO2 and MgO(100) at different annealing temperatures have been studied. Annealing above 110°С results in intermetallics formation in the films. The hcp-cobalt is grown in the films on SiO2 substrate, and the fcc-Co is observed on MgO(100) substrate. It is found that the stable α-Co3Sn2 intermetallic is formed at higher annealing temperature in film on MgO(100) substrate. We show that transformations related to mass transfer in the Sn/Co bilayers were up to 500°С and were finished upon reaching the thermodynamically equilibrium phase composition at this temperature.

Analysis of a Flexible Photoconductor, Manufactured with Organic Semiconductor Films.

This work presents the evaluation of the electrical behavior of a flexible photoconductor with a planar heterojunction architecture made up of organic semiconductor films deposited by high vacuum evaporation. The heterojunction was characterized in its morphology and mechanical properties by scanning electron microscopy and atomic force microscopy. The electrical characterization was carried out through the approximations of ohmic and SCLC (Space-Charge Limited Current) behaviors using experimental J-V (current density-voltage) curves at different voltages and under different light conditions. The optimization of the photoconductor was carried out through annealing and accelerated lighting processes. With these treatments, the Knoop Hardness of the flexible photoconductor has reached a value of 8 with a tensile strength of 5.7 MPa. The ohmic and SCLC approximations demonstrate that the unannealed device has an ohmic behavior, whereas the annealed device has an SCLC behavior, and after the optimization process, an ohmic behavior and a maximum current density of 0.34 mA/mm2 were obtained under blue light. The approximations of the device's electron mobility (μn) and free carrier density (n0) were performed under different light conditions, and the electrical activation energy and electrical gap were obtained for the flexible organic device, resulting in appropriate properties for these applications.

Abstract 551: Investigation of the antipoliferative effect of the Xylopia Aethiopicaextract in triple-negative breast cancer cells

Abstract Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer and has very limited treatment options. Xylopia Aethiopica (XA) is a common spice that is widely used in the regions of central and western Africa. It is known to have various pharmacological properties, one of which is anti-inflammatory activity. The anti-inflammatory effect may portend antiproliferative activity. We hypothesized that the extract of XA will exert antiproliferative activity against TNBC cells. The study aimed to establish the molecular mechanism underlying the antiproliferative activity of XA extract (XAE) against TNBC. The dried fruits of XA were crushed in a mixer and macerated using diethyl ether for 72 h. The macerate was subjected to vacuum and rotary evaporation to remove the organic solvent, and a stock solution was prepared in dimethyl sulfoxide (DMSO). Assessment of the efficacy of XAE was performed using serial dilutions (100 µg/ml, 50 µg/ml, 10 µg/ml, 5 µg/ml, and 1µg/ml) of the XAE stock solution, followed by in vitro testing against two TNBC cell lines (MDA-MB-231, and MDA-MB-468 cells). The cytotoxic effect of the XAE was then measured using the resazurin dye assay. XAE resulted in a concentration-dependent cell death in both cell lines. At the highest concentration (100 µg/ml), XAE induced cytotoxic cell death of 89% and 91% in MDAMB231 and MDAMB468 cells, respectively. This was consistent with IC50 values of 32.95 ± 1.32 µg/ml (MDAMB231) and 20.83 ± 1.05 µg/ml (MDAMB468). At the molecular level, western blot analysis of mitogenic markers associated with MAPK oncogenic signaling pathway demonstrated the inhibition of EGFR and AKT protein levels after a 48-h treatment. Acridine orange-ethidium bromide (AO/EB) staining showed a concentration-dependent induction of apoptosis in both cell lines. Flow cytometric analysis was performed to quantify the apoptotic cells. A significant increase of apoptotic cells was observed in treatment groups as compared to control after 72 h. Apoptotic induction was associated with increased p53 protein levels after 48 h treatment compared to control. The study results underscore the anticancer effects of XAE in TNBC cells mediated through induction of apoptosis. Citation Format: Shailvi Soni, Shail Rakesh Modi, Terrick Andey. Investigation of the antipoliferative effect of the Xylopia Aethiopicaextract in triple-negative breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 551.

Simulation and experimental study of temperature and mass distributions of indium metal in vacuum evaporation

The temperature field and spatial distribution of metal vapor (i.e., flow field) are critical for the purity and direct yield of metals. However, it is impossible to accurately determine the temperature field and distribution of the metal vapor in a vacuum furnace. This study developed a surface-to-surface thermal radiation and volume of fluid multiphase flow coupling model. The temperature distribution and mass distribution of indium vapor in the vertical vacuum furnace at different temperatures from 1423 to 1573 K under the condition of 1 Pa were obtained. The reliability of the model was verified by experimental data obtained under the same conditions as the simulation. The temperature difference between the inside and outside of the condensing plate was 30–45 K in the temperature interval of 1423–1573 K. The temperature difference between the inside wall and the center of the condensing plate was 10 K. The simulation results of indium vapor mass distribution match with the experimental values; the overall temperature error is 5%, and the volatility error is less than 15%. The model developed in this study can be used to predict the temperature field and metal vapor distribution in a vacuum furnace, which will significantly reduce experimental exploration and accurately guide the production practice of vacuum metallurgy. This will expand the application of vacuum metallurgy technology in metal purification, material preparation, waste recycling, and other industries. This can effectively reduce exploratory experiments in the process of vacuum distillation to prepare high-purity metals, reduce the consumption of resources and energy in the experiment and production process, and achieve clean production.

Clean and efficient recovery of silver from silver-tin alloys by vacuum evaporation-multistage condensation

The recycling of waste lead-free solder and the tin refining process generates large quantities of silver-tin alloys, which have a very high potential for recovery but for which there is no clean and efficient means of recovery. This study examined the saturation vapour pressure, separation coefficients, prediction of the T-x(y) phase diagram of the silver-tin alloys, and condensation rate to explore the feasibility of using vacuum evaporation-multistage condensation as a method for separating silver-tin alloys. The results suggest that in the process of vacuum evaporation, both silver and tin will evaporate, and the evaporability of silver is slightly greater than that of tin. In the process of multistage condensation, tin condenses before silver. Furthermore, the vacuum evaporation-multistage condensation method was experimentally validated. The results suggest that the TF consists of crude silver, with a silver content of 98.17 wt% and a silver distribution rate of 43.60%. The MP consists of a silver-tin alloy with 7.87 wt% silver content and exhibits a silver distribution rate of 53.06%. The RE is crude tin containing 0.27 wt% of silver content and a silver distribution rate of 5.14%. The separation rate of Ag is 96.64%. This study provides a clean and efficient method that is instructive for the recovery of Ag-Sn alloys.

Numerical investigation of solder joint shape for micro-spring package during vacuum vapor phase soldering

The novel micro-coil spring package has become a new choice for reliable applications in extreme temperature change, high-strength impact, long-term vibration and other harsh environments due to the advantages arising from its special packaging design. The study of solder joint shape is an important step in the characterization of the package reliability. By Ansys Fluent software, the finite volume method was applied to investigate the flow behavior of molten solder during vacuum vapor phase soldering and the volume of fluid model was used to track the solder melt front. The simulation results reveal the effect of two critical process parameters (solder volume and pad diameter) on solder joint shape in micro-spring array package. The fillet height of the solder joint increases with decreasing pad diameter and decreases with decreasing solder volume. The optimal solder volume is 0.07 mm3 coupled a pad diameter of 0.80 mm, producing suitable fillet height and nice concave fillet shape, which is in agreement with the real sample of micro-spring soldering joint. The good consistency between experiment and simulation proves that the finite element method can effectively predict the shape of the melted solder. This work paves the way for the optimization of the solder joint shape in the electronic assembly.

Highly reliable and stretchable OLEDs based on facile patterning method: toward stretchable organic optoelectronic devices

Stretchable displays attract significant attention because of their potential applications in wearable electronics, smart textiles, and human-conformable devices. This paper introduces an electrically stable, mechanically ultra-robust, and water-resistant stretchable OLED display (SOLED) mounted on a stress-relief pillar platform. The SOLED is fabricated on a thin, transparent polyethylene terephthalate (PET) film using conventional vacuum evaporation, organic-inorganic hybrid thin film encapsulation (TFE), and a nonselective laser patterning process. This simple and efficient process yields an OLED display with exceptional stretchability, reaching up to 95% strain and outstanding durability, enduring 100,000 stretch-release cycles at 50% strain. Operational lifetime and water-resistant storage lifetime measurements confirm that the TFE provides effective protection even after the nonselective laser patterning process. A 3 × 3 array SOLED display module mounted on a stress-relief pillar platform is successfully implemented, marking the first case of water-resistant display array operation in the field of SOLEDs. This work aims to develop practical stretchable displays by offering a reliable fabrication method and device design for creating mechanically robust and adaptable displays, potentially paving the way for future advances in human-conformable electronics and other innovative applications.

The Gas Chromatography Mass Spectrometry Analysis of an Ayurvedic Formulation Amruthadi Kashaya

Amruthadi Kashaya is a Ayurvedic formulation mentioned in the book Arogya Kalpadruma for the treatment of Pandu (anaemic syndrome), Kamala (jaundice) and Raktapitha (bleeding disorders). The Yoga contains six drugs namely Amrutha (Tinospora cordifolia), Vasa (Adhatoda vasica), Yashtimadhu (Glycyrrhiza glabra), Tiktha (Solanum anguivi), Ela (Elettaria cardamomum), Pichumantha (Azadirachta indica). This Kashaya is rich in phytoconstituents, such as phenolics, terpenoids, and lipids, which are known for their many biological benefits, including anti-inflammatory, anti-cancer, and antioxidant effects. The purpose of the current study is to use Gas Chromatography Mass Spectrometry (GCMS) analysis to identify the different types of bio molecules that are present in this Kashaya. Kashaya was prepared according to standard protocol. It was concentrated in the rotary vacuum evaporator, and the total soluble solid (TSS) obtained was used for GCMS analysis. The GCMS of Kashaya showed the presence of bio molecules such as 7 Hexadecanoic acid, methyl ester, Methyl tetradecanoate, Diethyl Phthalate, Dodecanoic acid, methyl ester, Methyl stearate, à-Terpineol, Methyl 8-methylnonanoate, 3-Cyclohexene-1-methanol, à, à,4-trimethyl-, acetate, Decanoic acid, methyl ester, 1,6,10-Dodecatrien-3-ol,3,7,11-trimethyl-, (E)-, Ethyl iso-allocholate, Spiro [2,4] hepta-4,6-diene, Butylated Hydroxytoluene, 9-Hexadecenoic acid, methyl ester, (Z) etc. à-Terpineol, 7-Hexadecenoic acid, methyl ester, Butylated hydroxytoluene, Nerolidyl acetate have antioxidant activity likewise some of the bio molecules have anti-inflammatory, antibacterial, anticancer activity. It is concluded that Ayurvedic formulation Amruthadi Kashaya contains many bio molecules having therapeutic actions.

Interfacial Engineering of Selenium‐Based Photodiodes for Extremely Low‐Noise Photodetection and Single‐Pixel Imaging

AbstractSelenium as one of the most historical semiconductors has been used for photovoltaics and photodetection, thanks to its excellent optoelectronic properties, superior stability, facile and low‐cost fabrication. However, commercialized Se‐based devices are mainly based on its amorphous state, which significantly limits the charge transport and requires relatively large bias voltage. The charge carrier dynamics of high‐performance crystalline Se thin films are barely reported, and related photodiodes have not been realized mainly limited by the large dark current and slow response speed. Here, poly‐crystalline Se thin films via vacuum evaporation, in situ thermal annealing, and engineered the interfaces with various metal electrodes are fabricated, which resulted in enhanced charge transport properties and reduced device leakage. The optimized Se photodiodes exhibited excellent performance metrics, including extremely low dark current density, decent specific detectivity, and superior stability. Furthermore, the optimized Se photodetectors are also introduced for single‐pixel imaging, which demonstrates excellent sensitivity and great potential for real applications.

Kinetics of indium separation and recovery from In–Sn alloys in ITO waste target products via vacuum evaporation

The environmentally friendly recycling of ITO waste material to regenerate indium resources is crucial for sustainability. The hydrogen reduction process, particularly the green and low-carbon technique of vacuum distillation, is crucial in the production of In–Sn alloys. However, a thorough examination of the mechanics underlying its evaporation throughout this process has yet to be performed. These mechanics are investigated in the present study for 92In–8Sn alloys under specific conditions, including temperatures between 1173 and 1373 K, pressure of 5 Pa, and crucible depth of 25 mm. The relationship between temperature and the rate of volatilization is mathematically represented as ω = e(a+b∙T). Furthermore, the equation ω = A2 + (A1-A2)/(1 + e(h-h0)/dh) was used to predict the dependency of the volatilization rate on crucible depth, ranging from 25 to 65 mm at 1323 K and 5 Pa. The mass transfer coefficients for the alloy at different temperatures were calculated, and a theoretical kinetic model for evaporation behavior indicated that vapor-phase mass transfer is the limiting step in the process of vacuum distillation of this alloy. This study presents a theoretical basis for the retrieval of In from the In–Sn alloy using vacuum distillation.

Stabilizing Single‐Source Evaporated Perovskites with Organic Interlayers for Amplified Spontaneous Emission

AbstractMetal halide perovskites are promising semiconductors with promising applications in optoelectronic and photonic technologies. When coherent emission applications are targeted, materials with lower lasing thresholds and increased stabilities must be developed to increase the performance under continuous wave optical pumping condition and finally allow the realization of the long sought‐after electrically pumped lasers. Perovskite multiple‐quantum‐wells (MQWs) can potentially ease the population inversion by confining photoexcitation within the heterostructure's wells, but their fabrication process and structural design still require a delicate optimization to make them valuable photonic platforms. Here, perovskite MQWs are fabricated based on organic semiconductors and CsPbBr3, using a facile and easily scalable sequential single‐source vacuum evaporation method. Perovskite with the organic interlayer shows radically enhanced phase stability, passivated defects, and improved radiative recombination properties. In this way, upon proper design of the heterostructure wells and barriers thicknesses, optically pumped amplified spontaneous emission can be achieved. This work reports an effective fabrication approach for perovskite MQWs, while providing a deeper understanding of their photophysical properties to foster their application as coherent light emitters.

Bioethanol Production from Water Hyacinth (Eichhornia crassipes) using Different Microbial Inoculants

Water Hyacinth (Eichhornia crassipes) is a weedy lignocellulosic material which represents the best substrate for the production of bioethanol in tropical countries due to its more availability and more biomass yield. For the fermentation and bioethanol production from water hyacinth, the different bacterial and fungal inoculants were used. Water hyacinth was obtained from ukkadam-valankulam lake, Coimbatore. These leaves were washed properly to remove soil and contaminants and dried for 3 hours at 120°C. It was grained into a fine powder and sieved using 1.5µm in diameter nylon sieve. The sieved material was cultured using different microbial culture such as Aspergillus oryzae, Aspergillus niger and Saccharomyces cerevisiae. After 21 days incubation, the culture was distilled using rotary vacuum evaporator and the produced bioethanol was analyzed by Fourier-transform infrared spectroscopy (FTIR) technique. The previous report showed, less yield only obtained using water hyacinth, potato peels, cassava peel and millet husks but this study produced highest yield using water hyacinth. This study indicated that water hyacinth is mostly available aquatic plant for the production of ethanol. The aim of current work is to understand the usage of water hyacinth as main substrate for bioethanol production using fungal inoculum. The microbial inoculants used for current study reported more potential for the production of bioethanol. This current work gives more economical value to water hyacinths and it can be cleared from all the waterways.

Development of an innovative technology using side stream vacuum evaporation for anaerobic digestion intensification and ammonia recovery

This work evaluated the application of a novel ex-situ vacuum-enhanced anaerobic digestion technology, IntensiCarbTM (IC), which decouples hydraulic retention time (HRT) from solids retention time (SRT), and strips ammonia at neutral pH. Four bench-scale reactors were daily fed with a 50/50 (v/v) mix of primary sludge (PS) and thickened waste-activated sludge (TWAS). Three reactors were operated at SRT 20d and intensification factors (IF = SRT/HRT) of 1 (control), 2, and 3, while the fourth was operated at an IF4 at SRT 30d. The findings showed that at an OLR of 5.1 ± 0.79 kgCOD/m3/d, which was 3 times the control, the COD and volatile solids reduction were maintained at around 50 %. The methanogenic community, the most vulnerable ones to high ammonia toxicity, was dominated by Methanosarcinaceae in IC digesters versus Methanoseata in the control digester. Specific methanogenic activity (SMA) and biomethanation potential tests (BMP) on the digestates indicated 35 %-62 % higher activity, relative to the control. The enhanced performance of the IC was due to a combination of increased biomass concentration, mitigation of ammonia toxicity at high loadings, and a microbial shift. Reduced digester size and increased organic loading rates (OLR) are two main benefits of IC-AD technology. Recovery of 50 % of influent total nitrogen in clean water is another promising aspect of IC-AD technology which enables running at high OLR but comparable ammonia concentration. The water recovery and a reduced N loading in recycle streams, thus minimizing the need for side-stream treatment and mainstream nitrogen removal, are additional benefits.

SERS detection of volatile gas in spoiled pork with the Ag/MoS2 nano-flower cavity/PVDF micron-bowl cavity (FIB) substrate.

Putrescine and cadaverine are significant volatile indicators used to assess the degree of food spoilage. Herein, we propose a micro-nano multi cavity structure for surface-enhanced Raman spectroscopy (SERS) to analyze the volatile gas putrescine and cadaverine in decomposing food. The MoS2 nano-flowers are inserted into a PVDF micro-cavity through in-situ growth, followed by vacuum evaporation technology of Ag nanoparticles to form an Ag/MoS2 nano-flower cavity/PVDF micron-bowl cavity (FIB) substrate. The micro-nano multi cavity structure can improve the capture capacity of both light and gas, thereby exhibiting high sensitivity (EF = 7.71 × 107) and excellent capability for gas detection of 2-naphthalenethiol. The SERS detections of the putrescine and cadaverine are achieved in the spoiled pork samples with the FIB substrate. Therefore, this substrate can provide an efficient, accurate, and feasible method for the specific and quantitative detection in the food safety field.

Impact of CdSeTe and CdSe film deposition parameter on the properties of CdSeTe/CdTe absorber structure for solar cell applications

In this study, the effect of depositing CdSeTe and CdTe layers at different substrate temperatures (STs) by evaporation in vacuum on the properties of the CdSeTe/CdTe stacks was investigated. First, CdSeTe layers in stack structure were grown at STs of 150 °C, 200 °C and 250 °C and then CdTe layers on the CdSeTe produced with the optimum temperature were coated at STs of 150 °C, 200 °C and 250 °C. The employing of STs up to 150 °C on both CdSeTe and CdTe films in CdSeTe/CdTe stacks demonstrated the presence of Te and/or oxide phases as well as the alloying, while more stable phase structures at higher temperatures. In the CdSeTe/CdTe stack, the increase in ST of CdSeTe promoted the alloying, while it weakened the alloy in which was applied in CdTe. It was concluded that under the applied experimental conditions, STs of 250 °C and 200 °C with the graded alloying structure, suitable absorption sites, more homogeneous surface morphology for potential solar cell applications would be more suitable for CdSeTe and CdTe, respectively. As a result, the application of ST to CdSeTe or CdTe in the stacks can be used as a tool to control the properties of the stack structure.

Investigation of Laser-Induced Graphene (LIG) on a Flexible Substrate and Its Functionalization by Metal Doping for Gas-Sensing Applications.

Graphene materials synthesized using direct laser writing (laser-induced graphene; LIG) make favorable sensor materials because of their large surface area, ease of fabrication, and cost-effectiveness. In particular, LIG decorated with metal nanoparticles (NPs) has been used in various sensors, including chemical sensors and electronic and electrochemical biosensors. However, the effect of metal decoration on LIG sensors remains controversial; hypotheses based on computational simulations do not always match the experimental results, and even the experimental results reported by different researchers have not been consistent. In the present study, we explored the effects of metal decorations on LIG gas sensors, with NO2 and NH3 gases as the representative oxidizing and reducing agents, respectively. To eliminate the unwanted side effects arising from metal salt residues, metal NPs were directly deposited via vacuum evaporation. Although the gas sensitivities of the sensors deteriorate upon metal decoration irrespective of the metal work function, in the case of NO2 gas, they improve upon metal decoration in the case of NH3 exposure. A careful investigation of the chemical structure and morphology of the metal NPs in the LIG sensors shows that the spontaneous oxidation of metal NPs with a low work function changes the behavior of the LIG gas sensors and that the sensors' behaviors under NO2 and NH3 gases follow different principles.

Casein micelle formation as a calcium phosphate phase separation process: Preparation of artificial casein micelles through vacuum evaporation and membrane processes

Industrial-scale production of artificial casein micelles (ACM) is required to produce dairy alternatives from recombinant casein. However, the currently common micelle preparation method of dropwise mixing casein and salt solutions is inefficient and may prove difficult to scale up. Here, we view casein micelle formation as a process driven by calcium phosphate phase separation in the presence of casein. On this basis, we developed novel routes to prepare ACM through vacuum evaporation, forward osmosis, or reverse osmosis. ACM prepared through these methods have similar properties and improved coagulation behaviour compared to those prepared through the currently common method and natural bovine casein micelles. The properties and functionality of the micelles depend on the preparation time and surface area available for micelle formation, with longer times and larger surfaces (i.e. lower fluxes) yielding smaller ACM that form firmer curds. These novel processes enable fast, efficient, and continuous production of ACM for application in future dairy alternatives. Industrial relevanceArtificial casein micelles can be used as a building block in the production of animal-free milk and cheese based on precision fermentation. The herein described novel processes to prepare artificial casein micelles are based on vacuum evaporation, forward osmosis, and reverse osmosis, which are mild, resource-efficient, and easily scalable processes. The processes require a dilute feed stream (e.g. caseins after precision fermentation), provide an elegant way to minimise local differences in the concentration of caseins and ions during micelle production, and offer the opportunity to design continuous micelle formation processes. These are all advantages over the existing methods to prepare artificial casein micelles with regard to industrial application.

The study of optical and electrical properties of AgInS2-based composite

sPhotovoltaic solar energy was one of the few sustainable and pollution-free energy sources. AgInS2 was a promising photovoltaic material, which had attracted considerable in long time due to its outstanding photovoltaic performance. Furthermore, the nanoparticles could improve the light absorption efficiency of absorption layer to enhance the photoelectric conversion efficiency of solar cell. In this paper, the suitable preparation methods of AgInS2 film and gold nanoparticles were used to improve the optical-electric performances of AgInS2-based solar cell. AgInS2 films were prepared by vacuum evaporation using different raw materials (Ag + In + S and Ag2S + In2S3) and then annealed at 400 °C or 425 °C. From absorption spectrum, the AgInS2 film, which was prepared by two components (Ag2S + In2S3) and annealed at 400 °C, had the highest absorption. And the transmission spectrum of the AgInS2 film was similar to that obtained from finite difference time domain simulation. Furthermore, this AgInS2 film was used to prepare AgInS2/CdS PN junction and AgInS2/gold/CdS PN junction. Due to the introduction of gold nanoparticles, the forward current of the AgInS2/gold/CdS PN junction increased an order of magnitude, but ideal factor and barrier height decreased, which meant that gold nanoparticles can promote carrier transport and improve electric property. As a result, this AgInS2/gold/CdS PN junction owned high absorption efficiency, low reverse saturation current and large barrier height, which meant huge application potential in solar cells field.