Showing papers on "Evaporation (deposition) published in 2016"
TL;DR: In this paper, the laser surface modification of 304S15 stainless steel to develop superhydrophobic properties and the subsequent application for homogeneous spot deposition was reported, with steady contact angle of ∼154° and contact angle hysteresis of ∼4°.
213 citations
TL;DR: In this article, lead-free CH3NH3SnBr3 and organometal halide perovskite films using two vapor deposition-based methods (i.e., co-evaporation and sequential evaporation) were deposited.
Abstract: We deposited lead-free CH3NH3SnBr3 – organometal halide perovskite films using two vapor deposition-based methods (i.e., co-evaporation and sequential evaporation) using SnBr2 and CH3NH3Br. We obtained comprehensive information about the structural and electronic properties of these Pb-free perovskite films. X-ray diffraction results confirmed the crystalline structure of MASnBr3. Using UV-Vis measurements, we determined the optical bandgap of these films to be ∼2.2 eV. On the basis of ultraviolet photoemission spectroscopy results, the work function and ionization energy were measured to be 4.3 and 6.1 eV, respectively. Solar cells employing such a perovskite film in a planar structure were fabricated with various hole transport layers (HTLs) (spiro-OMeTAD, C60, and P3HT). For perovskite films prepared by co-deposition, we obtained solar cell efficiencies ranging from 0.03 to 0.35%. On the other hand, when we used sequential deposition, a higher efficiency up to 1.12% was obtained using P3HT as the HTL. We confirmed that the low efficiency of MASnBr3 based perovskite solar cells is due to their relatively high resistance and the fast formation of Sn–Br oxide on the top surface by air exposure during fabrication. The sequential deposition method helped avoid such oxidation resulting in higher efficiencies.
121 citations
TL;DR: In this paper, the hybrid perovskite (BuNH3)2PbBr4 is grown on Si/SiO2 substrates by evaporation of a highly diluted stoichiometric solution of MeNH3Br and PbCl2 in anhydrous DMF/PhCl (1:1) (75 °C, 10 min).
Abstract: Atomically thin sheets of the hybrid perovskite (BuNH3)2PbBr4 are grown on Si/SiO2 substrates by evaporation of a highly diluted stoichiometric solution of MeNH3Br and PbCl2 in anhydrous DMF/PhCl (1:1) (75 °C, 10 min).
120 citations
TL;DR: In this article, the synthesis of methylammonium tin triiodide (MASnI3) thin films at room temperature by a hybrid thermal evaporation method and their application in fabricating lead (Pb)-free perovskite solar cells was reported.
Abstract: We report on the synthesis of methylammonium tin triiodide (MASnI3) thin films at room temperature by a hybrid thermal evaporation method and their application in fabricating lead (Pb)-free perovskite solar cells. The as-deposited MASnI3 thin films exhibit smooth surfaces, uniform coverage across the entire substrate, and strong crystallographic preferred orientation along the 〈100〉 direction. By incorporating this film with an inverted planar device architecture, our Pb-free perovskite solar cells are able to achieve an open-circuit voltage (Voc) up to 494 mV. The relatively high Voc is mainly ascribed to the excellent surface coverage, the compact morphology, the good stoichiometry control of the MASnI3 thin films, and the effective passivation of the electron-blocking and hole-blocking layers. Our results demonstrate the potential capability of the hybrid evaporation method to prepare high-quality Pb-free MASnI3 perovskite thin films which can be used to fabricate efficient Pb-free perovskite solar cells.
105 citations
TL;DR: In this paper, the authors present recent progress relating to metal-complex two-dimensional polymers, coordination nanosheets (CONASHs), an emerging class of material.
88 citations
TL;DR: Large-area light-absorbing perovskite films fabrication with a new facile and scalable gas pump method that can significantly enhance the solvent evaporation rate by 8 times faster and thereby produce an extremely dense, uniform, and full-coverage perovkite thin film.
Abstract: Control of the perovskite film formation process to produce high-quality organic–inorganic metal halide perovskite thin films with uniform morphology, high surface coverage, and minimum pinholes is of great importance to highly efficient solar cells. Herein, we report on large-area light-absorbing perovskite films fabrication with a new facile and scalable gas pump method. By decreasing the total pressure in the evaporation environment, the gas pump method can significantly enhance the solvent evaporation rate by 8 times faster and thereby produce an extremely dense, uniform, and full-coverage perovskite thin film. The resulting planar perovskite solar cells can achieve an impressive power conversion efficiency up to 19.00% with an average efficiency of 17.38 ± 0.70% for 32 devices with an area of 5 × 2 mm, 13.91% for devices with a large area up to 1.13 cm2. The perovskite films can be easily fabricated in air conditions with a relative humidity of 45–55%, which definitely has a promising prospect in ind...
82 citations
TL;DR: The method developed in this study has the capability of fabricating large active area devices showing a promising PCE of 4.8% and could be used in thin film based solar cells which require high-quality films leading to reduced fabrication cost and improved device performance.
Abstract: In this work, we report a physical deposition based, compact (cp) layer synthesis for planar heterojunction perovskite solar cells. Typical solution-based synthesis of cp layer for perovskite solar cells involves low-quality of thin films, high-temperature annealing, non-flexible devices, limitation of large-scale production and that the effects of the cp layer on carrier transport have not been fully understood. In this research, using radio frequency magnetron sputtering (RFMS), TiO2 cp layers were fabricated and the thickness could be controlled by deposition time; CH3NH3PbI3 films were prepared by evaporation &immersion (E &I) method, in which PbI2 films made by thermal evaporation technique were immersed in CH3NH3I solution. The devices exhibit power conversion efficiency (PCE) of 12.1% and the photovoltaic performance can maintain 77% of its initial PCE after 1440 h. The method developed in this study has the capability of fabricating large active area devices (40 × 40 mm(2)) showing a promising PCE of 4.8%. Low temperature and flexible devices were realized and a PCE of 8.9% was obtained on the PET/ITO substrates. These approaches could be used in thin film based solar cells which require high-quality films leading to reduced fabrication cost and improved device performance.
80 citations
TL;DR: In this paper, the authors presented an alternative route to supply excessive selenium (Se) for the deposition of Sb2Se3 thin films by the co-evaporation of Se and Sb 2Se3.
Abstract: In this work, we present an alternative route to supply excessive selenium (Se) for the deposition of Sb2Se3 thin films by the co-evaporation of Se and Sb2Se3. Scanning electron microscopy (SEM) images showed that additional Se modified the growth process and surface morphology of Sb2Se3 thin films. X-ray diffraction (XRD) patterns confirmed that this co-evaporation process enhanced the beneficiary preferred orientations, and capacitance–voltage (C–V) measurement showed that the carrier concentration of the Sb2Se3 absorber increased with the additional evaporation of Se. Accordingly, the efficiency of the devices employing co-evaporated Sb2Se3 absorber layers increased significantly from 2.1 to 3.47% with a open-circuit voltage (V OC) of 364 mV, a short-circuit current density (J SC) of 23.14 mA/cm2, and a fill factor (FF) of 41.26%.
77 citations
TL;DR: In this paper, the authors investigated the growth mechanism of few-layered graphene using the arc-discharge method under different environments including helium, oxygen-helium and hydrogenhelium, and showed that FG can only be produced in the presence of reactive gases.
57 citations
TL;DR: In this article, the effect of oxygen vacancy defects induced by tempering in reducing atmospheres and the aging behavior of titania thin films was investigated, and the results showed different nucleation and growth mechanisms between evaporated and sputtered thin films, resulting in severe influence on photocatalytic efficiency.
Abstract: In order to understand the variations in photocatalytic efficiencies of titania thin films prepared by different physical vapor deposition techniques, we studied the microstructure and resulting properties for the two widely used PVD methods, electron beam evaporation and reactive pulsed DC magnetron sputtering. In addition, we investigated the effect of oxygen vacancy defects induced by tempering in reducing atmospheres and the aging behavior. After deposition, several tempering series in oxygen, air, argon, and forming gas were carried out to control the amount of oxygen vacancy defects. The films were characterized with respect to crystallinity, texture, grain growth, grain structure, surface roughness, light transmission as well as band gap energy; the photocatalytic efficiency was measured via methylene blue degradation. The results show different nucleation and growth mechanisms between evaporated and sputtered titania thin films, resulting in severe influence on photocatalytic efficiency. The evaporated thin films exhibited homogeneous nucleation and growth, and stayed in the anatase structure even after tempering at 800 °C for 1 h. In contrast, the sputtered thin films started to form grains at the interface to the substrate and showed heterogeneous nucleation and growth. Moreover, the sputtered films already formed rutile when tempered at 600 °C for 1 h. The gain in surface area due to tempering, which promotes adsorption of photocatalytic reactants, was more pronounced in sputtered thin films (+29%) compared to evaporated thin films (+6%). Films with oxygen vacancy defects, preserved by tempering in argon or induced by tempering in forming gas, showed a large improvement in photocatalytic efficiency. However, aging of the samples over a period of 19 months lead to a progressive decline in efficiency, finally reaching the level of thin films tempered in air, which had remained stable over the same 19 month period. This strongly questions widely applied concepts based on improving the photocatalytic efficiency via oxygen vacancy defects.
53 citations
TL;DR: In this article, thin films of manganese (III) chloride 5,10,15,20-tetraphenyl-21H,23H-porphine (MnTPPCl) with different film thickness were deposited by an evaporation technique.
TL;DR: In this paper, the influence of window process conditions like process temperature, layer thickness and sputtering gas composition on the cell characteristics was investigated and a record cell efficiency of 18.2% with anti-reflective coating was obtained.
TL;DR: In this article, the influence of the laser wavelength on the deposition of copper tin sulfide (CTS) and SnS-rich CTS with a 248-nm KrF excimer laser and a 355-nm frequency-tripled Nd:YAG laser was investigated.
Abstract: The influence of the laser wavelength on the deposition of copper tin sulfide (CTS) and SnS-rich CTS with a 248-nm KrF excimer laser (pulse length τ = 20 ns) and a 355-nm frequency-tripled Nd:YAG laser (τ = 6 ns) was investigated. A comparative study of the two UV wavelengths shows that the CTS film growth rate per pulse was three to four times lower with the 248-nm laser than the 355-nm laser. SnS-rich CTS is more efficiently ablated than pure CTS. Films deposited at high fluence have submicron and micrometer size droplets, and the size and area density of the droplets do not vary significantly from 248 to 355 nm deposition. Irradiation at low fluence resulted in a non-stoichiometric material transfer with significant Cu deficiency in the as-deposited films. We discuss the transition from a non-stoichiometric material transfer at low fluence to a nearly stoichiometric ablation at high fluence based on a transition from a dominant evaporation regime to an ablation regime.
TL;DR: In this paper, various polymer deposition parameters have been investigated to improve the overall performance of the inverted type hybrid organic solar cells based on zinc oxide (ZnO)/poly(3-hexylthiophene) (P3HT).
Abstract: Various polymer deposition parameters have been investigated to improve the overall performance of the inverted type hybrid organic solar cells based on zinc oxide (ZnO)/poly(3-hexylthiophene) (P3HT). The polymer was deposited onto fluorine-doped tin oxide/ZnO nanorod arrays (NRAs) substrates via spin coating technique and followed by deposition of silver (Ag) using electron gun evaporation technique to build the devices. The objective of this work is to achieve the optimum device performance by selecting the best polymer concentration (25–40 mg/ml), spin coating speed (500–2000 rpm) and diluted polymer concentration (1–4 mg/ml) for ZnO NRAs surface modification. Experimental results showed that the device with P3HT concentration of 35 mg/ml, spin coating speed of 1000 rpm and ZnO NRAs surface modification with 1 mg/ml diluted P3HT solution exhibited the highest power conversion efficiency of 0.27 %. The surface roughness, P3HT top layer thickness and P3HT infiltration contributed to the significant photovoltaic performance improvement.
TL;DR: In this article, the authors compared planar solar cells in which the Sb2S3 absorber was deposited by either thermal evaporation or a solution-based process, and reported that the planar inorganic solar cell with evaporated Sb 2S3 has an efficiency of 1.7%.
Abstract: Sb2S3 is an alternative emerging material for chalcogenide solar cells. In this paper, we compare planar solar cells in which the Sb2S3 absorber was deposited by either thermal evaporation or a solution based process. The planar inorganic solar cell with evaporated Sb2S3 has an efficiency of 1.7%. This is much higher than the efficiency of 0.8% for solution deposited Sb2S3, and the highest known reported efficiency for a planar Sb2S3 solar cell with a CuSCN hole conducting layer. The evaporated Sb2S3 film is sulfur-rich, which results in flattening of the film surface after annealing at 300 °C, thereby reducing the likelihood of contact between the Sb2S3 and gold contact. In addition, the crystal size of the evaporated Sb2S3 film is about 30% larger than that of the solution deposited Sb2S3 and has different preferential crystal planes. These features make evaporation a promising deposition method for flat solar cells made from sulfur-based semiconducting materials.
Cross section image of the evaporated Sb2S3 solar cell with labels for each layer.
TL;DR: In this article, chromium films were deposited by cooled and hot target magnetron sputtering techniques with unbalanced magnetic field configuration at equal target power density and optical emission studies indicated the enhancement of deposition rates due to the evaporation of the hot Cr target.
Abstract: Chromium films were deposited by cooled and hot target magnetron sputtering techniques with unbalanced magnetic field configuration at equal target power density. The dependence of deposition rates of Cr films by the hot target magnetron sputtering on the power density was a non-linear at 27.5–31.5 W/cm2. The optical emission studies indicated the enhancement of deposition rates due to the evaporation of the hot Cr target. The chromium film structure was strongly depended on the factor of «hot target» and the target power density. Cr films were structured to (110) direction in the case of the hot target sputtering, for cooled target configuration – the preferred orientation was changed from (110) to (200) with the power density. Cr+ to Cr ratio and heat flow from the cathode to the substrate influenced on the coating hardness and adhesion. The Cr films with 9.84–12.79 GPa and the non-cracking behavior (up to 15 N) were obtained.
TL;DR: In this article, the structure, surface morphology and optical properties of TiO2 and Cu-TiO2 thin films were studied by X-ray diffrac r diffrac analysis.
Abstract: TiO2 and Cu-TiO2 thin films were deposited by e-beam evaporation and then annealed at 350 and 500 degrees C. Their structure, surface morphology and optical properties were studied by X-ray diffrac ...
Journal Article•
TL;DR: This work successfully assembles tungsten oxide nanowires on a centimeter scale on flat or patterned substrates by a simple evaporation-induced self-assembly method, and may pave the road for integrating aligned ultrathin semiconductor Nanowires into macroscopic devices for optoelectronic applications.
Abstract: Self-assembly of inorganic nanowires on a large scale directly on a substrate represents a great challenge. Starting from colloidally stable dispersions of ultrathin tungsten oxide nanowires, we successfully assemble the nanowires on a centimeter scale on flat or patterned substrates by a simple evaporation-induced self-assembly method. The capillary flow generated during the evaporation is responsible for the assembly of the nanowires. The concentration of the nanowire dispersion has a significant influence on the self-assembly behavior. Well-aligned tungsten oxide nanowire thin films are achieved when the concentration of the dispersion is in the range from 0.5 to 3.0 mg/mL. While at higher concentrations disordered nanowire thin films with cracks are formed, lower concentrations do not result in the formation of a continuous thin film. A macroscopic device based on the self-assembled tungsten oxide nanowires is fabricated, exhibiting good performance for UV light detection. Our results may pave the roa...
TL;DR: In this article, a thin film of SnS 2 obtained by close-spaced vacuum sublimation was irradiated by an Nd:YAG laser (λ = 532 ǫ ).
TL;DR: It is shown that the impurities floating in the vacuum chamber significantly impact lifetime values and reproducibility and found a correlation between lifetime and the device fabrication time.
Abstract: We evaluated the influence of impurities in the vacuum chamber used for the fabrication of organic light-emitting diodes on the lifetime of the fabricated devices and found a correlation between lifetime and the device fabrication time. The contact angle of the ITO substrates stored the chamber under vacuum were used to evaluate chamber cleanliness. Liquid chromatography-mass spectrometry was performed on Si wafers stored in the vacuum chamber before device fabrication to examine the impurities in the chamber. Surprisingly, despite the chamber and evaporation sources being at room temperature, a variety of materials were detected, including previously deposited materials and plasticizers from the vacuum chamber components. We show that the impurities, and not differences in water content, in the chamber were the source of lifetime variations even when the duration of exposure to impurities only varied before and after deposition of the emitter layer. These results suggest that the impurities floating in the vacuum chamber significantly impact lifetime values and reproducibility.
TL;DR: In this article, the effect of solvent evaporation rate and thermal annealing on the molecular packing morphology of a diketopyrrolopyrrole based organic photovoltaic donor material, DPP(TBFu)2, was investigated by means of atomistic molecular dynamics simulations.
Abstract: By means of atomistic molecular dynamics simulations, we have investigated the effect of the solvent evaporation rate and thermal annealing on the molecular packing morphology of a diketopyrrolopyrrole based organic photovoltaic donor material, DPP(TBFu)2, which displays excellent hole mobility. It is observed that slow evaporation of solvent will lead to a relatively high degree of molecular packing order while leaving many voids in the as-cast sample. Upon thermal annealing, the as-cast samples at both fast and slow evaporation rates become more compact and much more apparently at the slow evaporation rate. Interestingly, the effect of thermal annealing on molecular packing order depends on the solvent evaporation rates of the as-cast samples. Upon thermal annealing, the molecular packing order of the fast evaporated sample is enhanced with increased π–π stacks. In contrast, thermal annealing will decrease the degree of packing order for the slow evaporated sample since the orientations and conformations of the molecules at the aggregate boundaries are substantially modulated to squeeze the voids. Electrical network analyses point to the fact that the mesoscopic electrical connectivities for all the samples are quite effective and insensitive to the modifications of local molecular ordering due to the delocalized HOMO of DPP(TBFu)2 providing efficient intermolecular electronic interactions. The hole mobilities of all the fabricated samples are thus estimated to be similar and quite high. Finally, our simulations point to the fact that the modest enhancement of mobility upon thermal annealing is correlated with the increased density rather than the varied ordering of molecular packing. Our work provides an atomistic insight into the evolution of thin-film morphology of organic photovoltaic molecular materials during solution processing and thermal annealing treatments and sheds light on the correlation between the molecular structure, packing morphology and hole transport capability.
TL;DR: In this article, a platinum electrode submerged under NaCl electrolyte films of different thickness is used to measure the oxygen reduction current on a NaCl electrode submerged in NaCl fluid, which is supported by the numerical Multi-Ion Transport and Reaction Model (MITReM).
TL;DR: In this article, a reactive cathodic arc evaporation of Ti-Al-O-N was carried out in an industrial deposition system with two-fold substrate rotation and the structural and compositional evolution of the coatings was st...
Abstract: Reactive cathodic arc evaporation of Ti-Al-O-N was carried out in an industrial deposition system with two-fold substrate rotation. The structural and compositional evolution of the coatings was st ...
01 Jan 2016
TL;DR: In this article, Nanopowders (NP) of a pure and metal doped oxide were produced by a pulsed electron beam (PEB) evaporation method in low-pressure gas for biomaterials application.
Abstract: Nanopowders (NP) of a pure and metal doped oxide were produced by a pulsed electron beam (PEB) evaporation method in low-pressure gas for biomaterials application. Characteristics of NP were studied by XRD, high-resolution transmission electron microscopy, electronography, DSC-TG, inductively coupled plasma and pulsed cathode luminescence. NP evaporated in vacuum or inert gas possess the highest specific surface area (up to 338 m 2 /g) that specifies their high reactionary ability. Usually NP of 10–600 nm, which are formed from nanoparticles of 3–10 nm, consist of separate agglomerates in the size or chains of particles or mixture particles of different morphology. An important feature of the method of PEB evaporation was the formation of a significant amount of defects of various types in NP (twins, lattice distortion, point defects, etc.). The deficiency and presence of an amorphous phase in NP have affected their magnetic, luminescent, and other properties.
TL;DR: In this paper, different morphologies of zinc oxide (ZnO) were synthesized via a thermal evaporation-like technique without a catalyst introduction, and the influence of these morphologies on the photocatalytic activity was performed on a water wasted methylene blue.
Abstract: Different zinc oxide (ZnO) morphologies were synthesized via a thermal evaporation-like technique without a catalyst introduction. The morphology of ZnO has been controlled by varying the evaporation pressure of ambient air. X-ray diffractometer and field emission scanning electron microscope were used for crystallinity and morphology investigation, respectively. The X-ray data confirmed the purity and crystallinity of the as-prepared ZnO structure. A variation of the pressure led to different morphologies of ZnO nanostructure such as nanocombs and nanorods. The influence of these different morphologies on the photocatalytic activity was performed on a water wasted methylene blue. The results showed the geometry of one-dimensional nanostructures deposited at different pressures strongly controls the photocatalytic activity of ZnO. The most suitable photocatalytic performance was recorded for ZnO deposited at 0.15 Torr, which showed one-side nanocombs of long nails.
TL;DR: In this paper, the morphology and composition of tantalum oxide (Ta 2 O 5 ) thin films prepared by electron-beam (EB) evaporation and radio-frequency sputtering (SP) were investigated by grazing incidence X-ray diffraction (GIXRD), X-Ray reflectometry (XRR), atomic force microscopy, Fourier transformed infrared spectroscopy (FTIR), and XPS.
TL;DR: This work shows that the lateral size of graphene oxide (GO) nanosheets is strongly correlated with the concentration of graphite oxide present in the suspension asGraphite oxide is exfoliated by sonication, and fabricated organic thin film transistors using line-patterned reduced GO as electrodes.
Abstract: The size of chemically modified graphene nanosheets is a critical parameter that affects their performance and applications. Here, we show that the lateral size of graphene oxide (GO) nanosheets is strongly correlated with the concentration of graphite oxide present in the suspension as graphite oxide is exfoliated by sonication. The size of the GO nanosheets increased from less than 100 nm to several micrometers as the concentration of graphite oxide in the suspension was increased up to a critical concentration. An investigation of the evaporation behavior of the GO nanosheet solution using inkjet printing revealed that the critical temperature of formation of a uniform film, Tc, was lower for the large GO nanosheets than for the small GO nanosheets. This difference was attributed to the interactions between the two-dimensional structures of GO nanosheets and the substrate as well as the interactions among the GO nanosheets. Furthermore, we fabricated organic thin film transistors (OTFTs) using line-pat...
TL;DR: In this paper, an atomic force microscopy (AFM) was used to analyze the surface structure of molybdenum-coated polycyclic cation (MoCN) coatings.
Abstract: MoCN coatings have been formed by cathodic arc evaporation using the mixture of acetylene and nitrogen and pure molybdenum target. The surface structure, in conjunction with x-ray data, was analyzed by atomic force microscopy (AFM). The AFM results show differently shaped grain forms on the surface of coatings investigated. The increase in carbon in chemical coatings composition results in the reduction in surface grain size and the increase in roughness of the coatings.
TL;DR: It appears that extended surface characteristics and preferential crystalline orientation of as-deposited polycrystalline copper films control the growth kinetics of the copper oxide film.
Abstract: The oxidation of copper is a complicated process. Copper oxide develops two stable phases at room temperature and standard pressure (RTSP): cuprous oxide (Cu2O) and cupric oxide (CuO). Both phases have different optical and electrical characteristics that make them interesting for applications such as solar cells or resistive switching devices. For a given application, it is necessary to selectively control oxide thickness and cupric/cuprous oxide phase volume fraction. The thickness and composition of a copper oxide film growing on the surface of copper widely depend on the characteristics of as-deposited copper. In this Research Article, two samples, copper films prepared by two different deposition techniques, electron-beam evaporation and sputtering, were studied. As the core part of the study, the formation of the oxidized copper was analyzed routinely over a period of 253 days using spectroscopic polarized reflectometry-spectroscopic ellipsometry (RE). An effective medium approximation (EMA) model w...