Effect Of Annealing Treatment Research Articles

Effect of annealing treatment on the properties of inverted solar cells based on mixed halide perovskite

Abstract Organic–inorganic hybrid perovskites have attracted attention as successful light harvesting materials for solar cells with record breaking efficiencies. The photovoltaic performance of these devices is greatly dependent on the quality of the film which is dependent on the treatments employed. Thermal annealing treatment plays a key role in the production of good quality perovskite films. Generally, it triggers the reaction of initial materials to form the final perovskite layer. This work studies the annealing effect on the CH3NH3PbI3-xClx perovskite films based solar cells. It is found that the conversion requires sufficiently high temperatures to ensure the crystallization of the perovskite material. Furthermore, the as-fabricated perovskite solar cell annealed at 100 °C for 30 min exhibited the highest power conversion efficiency of 10.64% with short circuit current density of 19.75 mA/cm2, an open circuit voltage of 0.931 V, and a fill factor value of 57.83%.

Influence of Different Heat Treatment Temperatures on the Microstructure, Corrosion, and Mechanical Properties Behavior of Fe-Based Amorphous/Nanocrystalline Coatings

Fe-based amorphous/nanocrystalline coatings with smooth, compact interior structure and low porosity were fabricated via supersonic plasma spraying (SPS). The coatings showed outstanding corrosion resistance in a 3.5% NaCl solution at room temperature. In order to analyze the effect of annealing treatment on the microstructure, corrosion resistance and microhardness, the as-sprayed coating was annealed for 1 h under different temperatures such as 350, 450, 550 and 650 °C, respectively. The results showed that the number of oxides and cracks in the coatings presented an obvious increase with increasing annealing temperature, and the corrosion resistance of the coatings showed an obvious reduction. However, the microhardness of coatings showed an important increase. The microhardness of the coating could reach 1018 HV when the heat treatment temperature reached 650 °C. The X-ray diffraction (XRD) results showed that there appeared a number of crystalline phases in the coating when the heat treatment temperature was at 650 °C. The crystalline phases led to the increase of the microhardness.

Effect of annealing treatment on microstructure and mechanical properties of Al/Ni multilayer composites during accumulative roll bonding (ARB) process

Al/Ni multilayer composites are produced by accumulative roll bonding process and then annealed with different temperatures and time. Macroscopic images, microstructure and mechanical properties of Al/Ni multilayer composites are investigated. As for the macroscopic images, although there was an edge crack along the rolling direction at the third pass, the defect of composites was not serious and the forming quality of composites was relatively good. The yield strength and elongation of Al/Ni multilayer composites are improved after the annealing treatment; however, with the increase in annealing temperature and time, the yield strength and elongation of Al/Ni multilayer composites are decreased. During the process of annealing treatment, aluminum atoms diffuse in the way of vacancy diffusion, which results in the formation of Al3Ni intermetallic phase at Al/Ni interface and Kirkendall void in the aluminum side. The content of Al3Ni intermetallic phase and Kirkendall void would increase with the increase in annealing temperature and time.

Effects of alloying elements and annealing treatment on the microstructure and mechanical properties of Nb-Ta-Ti alloys fabricated by partial diffusion for biomedical applications.

Powder metallurgical (PM) Nb-25Ta-xTi alloys (x=5, 15, 25, 35at.%) were fabricated by the elemental powder sintering technology. Effects of alloying elements and annealing treatment on the microstructural evolution and mechanical properties were investigated by conducting various tests, including X-ray diffraction (XRD), scanning electron microscopy (SEM), electron probe microanalyses (EPMA), electron back scattered diffraction detector (EBSD), transmission electron microscopy (TEM) and tensile tests. The results indicated that the alloys showed a unique Nb-rich and Ta-rich dual structure due to the insufficient diffusion between powders. With the increase of Ti content, the β phase was always retained and the alloys exhibited a relatively high density in the range of 82.4% to 90.5%. Furthermore, owing to a higher diffusion coefficient of Ti and the strengthening effect of solid solution, the volume shrinkage and tensile strength both increased along with the increase of Ti content. After the annealing treatment was introduced, the microstructure became more homogeneous and fine equiaxed grains appeared, which induced a decrease in modulus and better ductility. The Nb-25Ta-25Ti alloys exhibited a good in vitro biocompatibility due to the chemical components and the introduce of surface pores. The PM Nb-Ta-Ti alloys were promising for biomedical applications in tissue engineering after evaluated both mechanical properties and in vitro biocompatibility.

Effect of annealing treatment on the microstructure and mechanical properties of Fe-18Mn-0.8C-0.2 V TWIP steel

The microstructure and mechanical properties of TWIP steels under different annealing treatments were investigated by static tensile tests, OM, TEM, and EBSD. Results show that the TWIP steel was dominated by full austenitic grains before and after tensile deformation. The TWIP steel exhibited optimal mechanical performance under the annealing treatment at 1000 °C, with the highest initial strain hardening rate (dσ/dε). The grain size increased with the increasing annealing temperature, and the relationship between strain hardening and true strain turns into three stages from two stages. The strain hardening index (n) has the same transition trend under different annealing temperatures when ε < 0.07. With the increase of true strain, the n reached a maximum value of 0.53, 0.62, 0.70 at the annealing temperatures of 800 °C, 900 °C, 1000 °C, respectively. With the increase of the annealing temperature, the elements of V or Ti compounds exhibited a decrease in content but an increase in size. The fracture of the TWIP steel exhibited typical equiaxed dimples. Deformation twins with different orientations were generated within the austenitic grains after the deformation process. With the increase of annealing temperature, the decreased space between twins results in the strengthening of the TWIP effect.

Effect of heat treatment on friction and wear behavior of Ni-based thermal spray coating deposited on Z200C12 steel

The present work investigates Ni-based alloy coating deposited on Z200C12 steel using thermal spray technique. It focuses on the effect of annealing treatment at 500 °C for different durations of 2 h, 4 h and 8 h on friction and wear behavior of the coatings. Phase composition, substrate/coating interface, elemental distribution and coating wear tracks morphologies were characterized using x-ray diffraction, scanning electron microscope, energy dispersive spectrometer and x-ray mapping techniques. Friction and wear resistance of the as-sprayed and annealed coatings were studied by determining the coefficients of friction and wear rates using an Al2O3 ball under a load of 6 N. The results showed that the heat-treated coating at 500 °C for 2 h exhibited the highest wear resistance and a substantially lower friction coefficient as compared to all other coatings. The observed wear mechanisms mainly involved fragmentation of splats, brittle fracture, and abrasive wear.

Effect of Annealing Treatment on Optical and Electrical Properties of PCDTBT:Graphene Hybrid Structure for Photovoltaic Application

Indium tin oxide (ITO)/poly[N-9′-heptadecanyl-2,7-carbazole-alt-5,5-(4,7-di-2-thienyl-2′,1′,3′-benzothiadiazole)] (PCDTBT):graphene/Al structures have been elaborated. By applying a specific elaboration method, we succeeded in dispersing expandable graphene oxide in organic solvent (N,N-dimethylformamide, DMF) to obtain graphene oxide and insert it into a PCDTBT matrix. The effect of annealing treatment of PCDTBT:graphene films on the optical and electrical properties were studied. The obtained results showed a remarkable effect of the annealing treatment on the optoelectronic properties. The ultraviolet–visible (UV–Vis) spectra showed that the light harvesting was increased and the orderly stacking of the polymer chains was enhanced. The photoluminescence results showed a red-shift of about 10 nm in case of heat treatment at 150°C, related to an increase of the conjugation length of the polymer chains. The electrical parameters, such as the series resistance (Rs), ideality factor (n), and barrier height (ϕb), were calculated. We found that thermal annealing reduced both the series resistance Rs and barrier height value ϕb, significantly. These results indicate that annealing treatment improves the transport phenomenon in the active layer. In addition, the Log(J)–Log(V) curves suggested that the charge transport is governed by a space-charge-limited mechanism current. The effective carrier mobility (μeff) was on the order of 10−5 cm2/V.

Stereometric and scaling law analysis of surface morphology of stainless steel type AISI 304 coated with Mn: a conventional and fractal evaluation

The purpose of this study is to determine the micromorphology of stainless steel type AISI 304 coated with thin films of Manganese post-annealed by the flow of nitrogen at different annealing temperatures using atomic force microscopy (AFM) and fractal/multifractal analyses. The coated samples were annealed with a nitrogen flow of 400 sccm at four different temperatures of I group, 473 K; II group, 623 K; III group, 773 K; and IV group, 923 K. AFM was used to image the 3D surface micromorphology in tapping mode, on square areas of 2 × 2 μm2. The approaches in both measurement and data analysis when using AFM analysis and surface fractal/multifractal analyses are essential for the correct interpretation of 3D surface topographic features and offer the 3D surface texture parameters and surface fractal dimension. The more irregular surface (Sq = 22.23 nm) was found in IV group, and the more regular surface (Sq = 5.86 nm) was found in II group. The result shows the effect of annealing treatment on fractal/multifractal characteristics of surfaces.

Optimizing the electromagnetic properties of the FeCoNiAlCrx high entropy alloy powders by composition adjustment and annealing treatment

High entropy alloy powders are promising candidates for new microwave absorbents due to its advantages in corrosion resistance, heat resistance and soft magnetic properties. In this work, flake-shaped FeCoNiAlCrx (x = 0.1, 0.3, 0.5, 0.7, and 0.9, in molar ratios) alloy powders are prepared by mechanical alloying, and then annealed at 500 °C. The experimental results show that the milled and annealed FeCoNiAlCrx powders contain similar FCC and BCC phase structure. The addition of Cr element results in more flattened powder particles and more polarization sites, which enhances the surface polarization and ultimately increases the real and imaginary parts of complex permittivity (ε′ and ε″). The real and imaginary parts of complex permeability (μ′ and μ″) decrease first and then increase as the proportion of Cr increases. The minimum reflection loss (RLmin) is improved and moves to the low frequency region (11.20 GHz to 8.23 GHz) as the proportion of Cr increases. After annealing, the enhanced saturation magnetization (Ms) increased μr, and the improvement of crystallinity also increased εr. For FeCoNiAlCr0.9 samples, annealing treatment directly improves the minimum reflection loss from −26.88 dB (8.23 GHz) to −47.55 dB (7.375 GHz), suggesting the positive effects of annealing treatment on reflection loss. All the above findings provide experimental and theoretical basis for FeCoNiAlCrx high entropy alloy powders as absorbing material.

Effect of annealing treatment on PVDF nanofibers for mechanical energy harvesting applications

Piezoelectric nanofibrous films with superior flexibility have attracted the emerging applications including sensors and actuators, piezoelectric nanogenerators (PNG) and energy storage devices. Herein, polyvinylidene fluoride (PVDF) piezoelectric nanofibrous film have been made by the electrospinning technique and been exposed to annealing as a post processing treatment at 40, 70, 100 and 130 °C for 4 h in air-flow oven. Four kinds of samples annealed at various temperatures have been pointed out as PVDF40, PVDF70, PVDF100 and PVDF130, respectively. The crystalline phases and thermal responses of the annealed film have been examined with XRD, FTIR and DSC. Also, mechanical and electroactive investigations exhibited that annealing treatment has effectively enhanced the dielectric constant, piezoelectric coefficient and the polar β-phase. Moreover, the annealed PVDF film acts as an effective layer of the PNG with enhanced crystalline structure and polar β-phase fraction. When the film is annealed at 100 °C, the voltage output of the PNG can attain maximum microstrain of 1000 με. The developed PVDF100 nanofibrous film-based PNG can generate output voltage of 0.516 V and 0.505 V with a tensile and compressive microstrain measured using the microstrain indicator of 1000 με. It shows better results compared to PVDF40 of 0.221 V. The enhanced voltage output of the PNG is recognised to be the collaborative involvement of the electrospinning and annealing treatment which could improve the piezoelectric response of the annealed film. This work presents that the annealed PVDF nanofibrous film based highly compliant PNG could be a promising candidate for flexible self-powered electronic applications.

Microstructures and properties of TiCp/Al coating synthesized on Ti–6Al–4V alloy substrate using mechanical alloying method

A TiCp/Al coating was synthesized on the Ti–6Al–4V alloy substrate by mechanical alloying method. The microstructure, the mircohardeness, the friction and wear resistance and the high-temperature oxidation resistance of the coating, as well as the effect of annealing treatment on them were investigated. The results showed that the coating had a TiC particles reinforced Al matrix composite structure in which the reinforcing particles were uniformly dispersed in the matrix. The microhardness, the wear resistance and the oxidation resistance were improved because of the as-synthesized coating. After annealing treatment, the coating formed a bi-layer structure, including an outer TiCp/Al composite layer and an inner Al3Ti layer. The outer layer had low microhardness and tended to be flaked in both friction and oxidation processes. The inner layer showed more than 5 times of microhardness values of the outer layer and had favorable wear resistance. But during long-time oxidation process, the inner layer had a stronger tendency of forming microdefects compared with the unannealed coating. In general, the TiCp/Al composite coating could protect the substrate from being severe worn or oxidized. The annealing treatment to the coating was conductive to the further improvement of its microhardness and wear resistance, but had limited effects on its oxidation resistance.

Effect of annealing treatment on the structure and performance of transparent conductive AZO/Al2O3 bi-layer films

Transparent and conductive Al-doped zinc oxide (AZO) films have a wider band gap, good optoelectronic characteristics, inexpensive and nontoxicity, compared with indium tin oxide (ITO). In this study, AZO films are deposited onto Al2O3/glass using magnetron sputtering. After deposition, both conventional annealing (CA) and rapid thermal annealing (RTA) are used to obtain a high quality AZO/Al2O3/glass bi-layer. The XRD and TEM images show that the film has a poly-crystalline nature with a hexagonal wurtzite-type structure. As the annealing temperature is increased, the intensity of the (0 0 2) diffraction peak increases and there is decrease in the full width at half maximum, which indicates that the films undergo a thermally activated process of grain growth and exhibit improved crystallization. RTA produces a larger grain, a greater carrier concentration and better crystallinity than CA. After RTA at 500 °C, the AZO/Al2O3 bi-layer films result in the lowest electrical resistivity, the highest optical transmittance and a good figure of merit. The bi-layer films are subject to a pull-off adhesion strength test, which shows that have a superior peel off stress. The experimental results show that these AZO/Al2O3 bi-layer films have good optoelectronic performance and adhesive strength.

The effect of annealing treatment on the evolution of the microstructure, the mechanical properties and the texture of nano SiC reinforced aluminium matrix alloys with ultrafine grained structure

In the present work, an ultrafine grained (UFG) aluminium matrix nano composite (UFANC) was prepared through a cryogenic deformation based manufacturing route. The influence of annealing on the microstructural evolution, mechanical properties and the crystallographic texture of the developed UFANC material was studied and compared with the unreinforced ultrafine grained counterpart (UFG). The presence of nano particles during deformation led to an increased generation of dislocations in the matrix. At low annealing temperatures high density dislocations provided a higher driving force for recrystallization in the UFANC. At high temperatures the grain growth in the UFANC was restricted by the pinning action of the nano reinforcement. This resulted in a higher activation energy for grain growth compared to the UFG counterpart. As a result, the UFANC retained high strength and possessed a fine microstructure even at annealing temperatures of up to 250 °C. The evolution of the texture during annealing was influenced due to the deformation at cryogenic environment. The presence of nano particles led to a more random texture in the UFANC compared to the UFG counterpart during annealing.

Estimation of mass transfer rate and primary drying times during freeze-drying of frozen maltodextrin solutions based on x-ray μ-computed tomography measurements of pore size distributions

The study presents a method to estimate the mass transfer rate during primary drying based on μ-computed tomographic measurements of a freeze-dried cake. The study was carried out in a defined setup in a lyomicroscope and confined geometry in which freezing occurred under homogeneous nucleation, and drying under mass-transfer-limited conditions. Pore size distribution, effective diffusivity, and primary drying rates of maltodextrin solutions at different weight concentrations (5%, 10%, and 20% (w/w)) and different cooling rates were determined. Furthermore, the effect of annealing treatment on primary drying rate was studied. Two different annealing treatments were tested, one for 90 min at −10 °C and another for 180 min at −5 °C. It was shown that solid concentration and annealing above Tg’ have the strongest impact on pore size and, subsequently, on primary drying rate. Therefore annealing represents a powerful tool to accelerate primary drying which is the most time-consuming step during lyophilisation.

The Effect of Annealing on Microstructure and Mechanical Properties of Selective Laser Melting AlSi10Mg

The effect of annealing treatment on SLM AlSilOMg on microstructure and mechanical properties has been investigated. It is observed that, with the increase of the temperature, the melt pools gradually become blurred and completely disappear when the temperature rises to 320°C. The microhardness and strengths of as-built samples are the highest due to the solid solution strengthening together with grain refinement strengthening. After heat treatment, the microhardness and strengths all decrease due to the weakening of solid solution strengthening but the elongation increases.

One-step methylammonium lead bromide films: Effect of annealing treatment

With the rapid increase of efficiency up to 23% during the past few years, hybrid organic-inorganic metal halide perovskite solar cells (PSCs) have become a research “hot spot” for many solar cell researchers. Hybrid perovskite structures have been obtained from methylammonuim lead bromide solutions deposited by one step spin coating deposition method. In this work, the effects of annealing temperature of the MAPbBr3 films and devices have been investigated in details. By tuning the variation of the temperature, the properties including photoluminescence, crystallinity and morphology of perovskite films together with device performance have been affected significantly by the annealing temperature. The devices annealed with 70 °C shows the best device performance and exhibit a maximum Fill Factor around 76.5 and a maximum efficiency at 2.89%.

Effect of annealing treatment on the dry sliding wear behavior of copper

The effect of annealing on the wear behavior of commercial grade pure copper (Cu) was evaluated by performing unlubricated pin-on-disc wear tests of as–received and annealed samples under 0.1–10 kgf normal load. It was found that annealing at 800 °C for 24 h led to an increase of grain size of Cu from ~ 6.7 to ~ 15.3 µm and a decrease in hardness. Wear rates of both samples increased while the friction coefficients decreased with increasing normal load. Subsurface microstructure evolution and wear debris were characterized by high resolution electron backscattered diffraction (EBSD) and transmission electron microscopy (TEM) after wear tests. Dynamic recrystallization and abnormal subsurface grain growth were observed in both samples under high load. Finally, the effect of annealing on the microstructure evolution and wear resistance of Cu were discussed.

Effect of Annealing Treatment on Mechanical and Magnetic Softening Behaviors of Cold Rolled Interstitial-Free Steel

The recovery and recrystallization behaviors of low-carbon interstitial-free steel are investigated at different annealing temperatures (200-690 °C) through correlation between the changes in magnetic parameters (coercivity and r.m.s. voltage), hardness, tensile strength and high-angle grain boundary fractions (HAB). Magnetic parameters and tensile strength show a significant change within recovery region (200-500 °C), while the hardness variation is very minimal at this temperature region. On the other hand, the hardness is abruptly changed compared to magnetic properties at higher annealing temperature (550-640 °C). The grain boundary characteristics and microtexture evolution occurring at recrystallization regime are evaluated by orientation imaging microscopy (OIM) and orientation distribution function (ODF) through electron backscattered diffraction (EBSD). The increase in recrystallization fraction noticeably affects microtexture property, justifying with the strengthening of γ-fiber, weakening of α-fiber and disappearance of rotated cube component with increasing annealing temperatures.

Colossal dielectric behavior of Co-doped TiO2 ceramics: A comparative study

The (Nb + In) co-doped rutile TiO2 ceramics were synthesized by spark plasma sintering (SPS) and traditional solid-state sintering (TS) techniques, respectively. Highly-density co-doped rutile TiO2 ceramics are prepared with the SPS method by 20 min, whereas it takes nearly 30 h with the TS method. It is observed that SPS ceramics showed smaller and uniform grain size, and better densification than TS counterparts. Both sets of the co-doped TiO2 ceramics showed single rutile phase according to X-ray diffraction (XRD) results. X-ray photoelectron spectroscopy (XPS) is adopted to detect and compare the element-valence-state of both sets of the co-doped TiO2 ceramics. The dielectric response, impedance spectroscopy (IS), and the effects of annealing treatment are systematically investigated, which could not only be helpful for optimizing their dielectric properties, but also shed the light on the colossal dielectric mechanism.

The promotion of Indeno [1, 2-b] flourene-6, 12 dione thin film to be changed into stable aromatic compound under the effect of annealing treatment

Thin films of Indeno [1, 2-b] flourene-6,12-dione (I[1, 2-b]F dione) were performed by the thermal vacuum evaporation technique. The identifications of a thin film such as structure, molecular structure and surface morphological were determined before and after annealing temperature using Fourier-transform infrared (FTIR), X-Ray diffreaction (XRD) and Scan electron microscopy (SEM). FTIR spectrum showed a diminishing of C═O bonds after annealing treatment. The analysis of XRD clarified that I[1, 2-b]F dione in its powder form is orthorhombic with space group P222. On the other hand, the as-deposited thin films were realized by amorphous nature, while the annealed I[1, 2-b]F dione thin films showed polycrystalline nature. The calculation of the average crystallite sizes proved that the annealed I[1, 2-b]F dione thin films were characterized by their nanostructure property. The SEM images illustrated that the aggregation of the particles has the formation of the nano-rod shape associated with average width in the range of 120–150 nm for the as-deposited thin film, while the average width of the branched nano-rod shape for the annealed thin films was observed to be in the range of 150–200 nm. The transmittance and reflectance spectrum at normal incidence of light in the range 190–2500 nm were employed to discuss the optical properties of as-deposited and the annealed I[1, 2-b]F dione thin films. Our conceptions elucidated that the optical transition type of I[1, 2-b]F dione films is the indirect allowed transition. The values of the fundamental energy gap for the as-deposited and the annealed films at 473 K were calculated out be 3.41 and 3.70 eV respectively. The dispersion of the refractive index was studied according to the single oscillator model. Moreover, the third-order nonlinear susceptibility and the nonlinear refractive index for I[1, 2-b]F dione thin films were calculated.