High-temperature Annealing Research Articles

Exploration and Optimization of the Polymer-Modified NiOx Hole Transport Layer for Fabricating Inverted Perovskite Solar Cells.

The recombination of charge carriers at the interface between carrier transport layers such as nickel oxide (NiOx) and the perovskite absorber has long been a challenge in perovskite solar cells (PSCs). To address this issue, we introduced a polymer additive poly(vinyl butyral) into NiOx and subjected it to high-temperature annealing to form a void-containing structure. The formation of voids is confirmed to increase light transmittance and surface area of NiOx, which is beneficial for light absorption and carrier separation within PSCs. Experimental results demonstrate that the incorporation of the polymer additive helped to enhance the hole conductivity and carrier extraction of NiOx with a higher Ni3+/Ni2+ ratio. This also optimized the energy levels of NiOx to match with the perovskite to raise the open-circuit voltage to 1.01 V. By incorporating an additional NiOx layer beneath the polymer-modified NiOx, the device efficiency was further increased as verified from the dark current measurement of devices.

Comprehensive study on scale-induced heterogeneity of (Ni2CrCo)94Nb3V3 high-entropy alloy variable-width thin-walled structure fabricated by additive manufacturing

Laser additive manufacturing (AM) shows excellent advantages in near-net shape of complex parts. In this work, the (Ni2CrCo)94Nb3V3 high-entropy alloy variable-width thin-walled structures were fabricated by directed energy deposition, and its microstructure and mechanical properties at the narrow and wide ends were systematically studied in the printed and different heat treatment states. In the printed state, the 〈001〉 crystallographic orientation along the building direction and the 〈111〉 crystallographic orientation along the scanning direction are formed at the narrow and wide ends of the sample, respectively. The preferred crystallographic orientation is eliminated and numerous annealed twins are occurred at high-temperature annealing, while the original grain morphology and crystallographic orientation is not changed significantly after direct aging. In the printed state, the yield strength and ultimate tensile strength of the wide end are increased by 10.69 % and 11.60 % compared with that of the narrow end, and the elongation is decreased by 18.74 %. The differences in tensile properties at the narrow and wide ends of the sample are mainly related to the crystallographic orientation and dislocation density, without taking the statistically stored dislocations into account. The strength of both narrow and wide ends is significantly increased, but the difference in tensile performance between them is not changed through direct aging. In addition, the strength is slightly decreased and the difference in tensile properties between the narrow and wide ends is eliminated by high-temperature annealing. The results present in the current study provide new insights for the LAM optimizing design of thin-walled parts with complex structures.

Microstructure and Unusual Ferromagnetism of Epitaxial SnO2 Films Heavily Implanted with Co Ions

In this work, we have studied the microstructure and unusual ferromagnetic behavior in epitaxial tin dioxide (SnO2) films implanted with 40 keV Co+ ions to a high fluence of 1.0 × 1017 ions/cm2 at room or elevated substrate temperatures. The aim was to comprehensively understand the interplay between cobalt implant distribution, crystal defects (such as oxygen vacancies), and magnetic properties of Co-implanted SnO2 films, which have potential applications in spintronics. We have utilized scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometry (VSM), differential thermomagnetic analysis (DTMA), and ferromagnetic resonance (FMR) to investigate Co-implanted epitaxial SnO2 films. The comprehensive experimental investigation shows that the Co ion implantation with high cobalt concentration induces significant changes in the microstructure of SnO2 films, leading to the appearance of ferromagnetism with the Curie temperature significantly above the room temperature. We also established a strong influence of implantation temperature and subsequent high-temperature annealing in air or under vacuum on the magnetic properties of Co-implanted SnO2 films. In addition, we report a strong chemical effect of ethanol on the FMR spectra. The obtained results are discussed within the model of two magnetic layers, with different concentrations and valence states of the implanted cobalt, and with a high content of oxygen vacancies.

Fabrication of a coral-like barium titanate nano-piezoelectric coating and its effect on promoting osteogenic differentiation of rat bone marrow mesenchymal stem cells in vitro

Objective: To investigate the biocompatibility of coral-like barium titanate nano-piezoelectric coatings and the influence of ultrasound-excited piezoelectric effect on the early osteogenic differentiation. Methods: The barium titanate nano-piezoelectric coating (the coating group) was prepared on the surface of titanium metal by anodic oxidation, hydrothermal reaction and high-temperature annealing, and polished titanium specimens were used as control group. The surface morphology, composition, and crystal phase and hydrophilicity of the two groups of titanium specimens were characterized using scanning electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy and contact angle meter. The piezoelectric properties of the materials were characterized by piezoresponse force microscopy. Rat bone marrow mesenchymal stem cells (BMSC) were cultured and identified and seeded the surface of titanium specimens in two groups. The cells seeded on blank culture plates were used as blank group. After low intensity pulsed ultrasound intervention, cell proliferation and live/dead staining were detected to evaluate cytocompatibility of the coatings. Alkaline phosphatase (ALP) activity of each group was detected by ALP staining kit, and the expression of osteogenesis-related genes [integrin, bone morphogenetic protein 2 (BMP-2), Runt-related transcription factor 2 (RUNX2)] was detected by real-time fluorescent quantitative PCR (RT-qPCR) to evaluate the effect of the coating on promoting the early osteogenic differentiation of BMSC. Results: The surface of titanium specimens in the coating group showed a uniform coral-like morphology, and the diameter of the coral tentacles was 70-100 nm. The main component was tetragonal barium titanate. The surface hydrophilicity of the coating group (water contact angle 10.12°± 0.93°) was significantly better than that of the control group (water contact angle 78.32°±0.71°) (F= 10 165.91, P<0.001). The coating has a stable piezoelectric property with a piezoelectric constant of about 5 pC/N. Cell experiments showed that, with or without ultrasound, the cell proliferation activity of the coating group was significantly lower than that of the blank group and the control group on the third day (P<0.05). On the fifth day, with or without ultrasound, there was no significant difference in cell proliferation activity between the three groups (P>0.05). After 7 days of culture, the ALP activity of the coating group was significantly higher than that of the blank group and the control group (P<0.05). The results of RT-qPCR showed that the mRNA expression of integrin and BMP-2 in the coating group with ultrasound was significantly higher than that in the other groups with ultrasound, and was higher than that of the coating group without ultrasound (P<0.05). The expression of integrin mRNA in the control group with ultrasound was significantly higher than that in the control group without ultrasound (P<0.05). The expression of RUNX2 mRNA in the coating group with ultrasound was significantly higher than that in the coating group without ultrasound (P<0.05). Conclusions: The coral-like barium titanate nano-piezoelectric coating exhibits favorable biocompatibility and stable piezoelectric property, and facilitates the early osteogenic differentiation of BMSC under the excitation of low-intensity pulsed ultrasound.

S-doped carbon anchoring PtCo intermetallic nanoparticles for efficient proton exchange membrane fuel cells based on molecularly engineered design

Enhanced ordered intermetallic compounds excel in catalyzing the oxygen reduction reaction (ORR). We introduce a novel synthesis strategy based on molecularly engineered to address challenges in high-temperature annealing. It involves the synthesis of carbon platforms with rich edge sites, which serve as effective anchoring points for nanoparticles. By utilizing sulfur anchoring, we synthesize ordered Pt–Co intermetallic with Pt-rich shells (o-PtCo@Pt) that exhibit remarkable ORR performance. Ordered arrangement of Pt–Co endows Pt-shell with compression stress and enhances the oxidation resistance of Pt/Co sites. O–PtCo@Pt exhibits high mass activity (MA, 0.53 A mgPt−1) and specific activity (SA, 1.17 mA cm−2). It exhibits remarkable as cathodic catalyst in proton exchange membrane fuel cells. It achieves power density of 1.14 W cm−2 at 2.0 A cm−2, with MA of 0.50 A mgPt−1 at 0.9 V. It maintains stability with only 8 % power density loss after 30,000 cycles, retaining MA of 0.35 A mgPt−1.

Overcoming the strength-ductility trade-off dilemma in austenitic lightweight steel via stepwise controllable intragranular dual nanoprecipitation

The strength-ductility trade-off is an inevitable scenario in precipitation-hardened austenitic lightweight steels. The reduction in ductility is due to the shearing of κ′-carbides by dislocations, resulting in limited work hardening capability. Conversely, non-shearable B2 particles can effectively improve the work hardening rate. However, these B2 particles tend to precipitate along grain boundaries and coarsen due to their incompatibility with the austenite matrix, resulting in negligible strengthening effect or even brittleness. We propose a stepwise controllable dual nanoprecipitation strategy to overcome the strength-ductility trade-off. To implement this strategy, we develop a manufacturing process that includes a high-temperature annealing treatment and a three-step aging process (700 °C/15min + 900 °C/15min + 450 °C/1 h). The higher annealing temperature increases the supersaturation of solute atoms in the austenite matrix, which improves the chemical driving force for the precipitation of intragranular B2 particles during aging at 900 °C. Additionally, the coarsened κ′-carbides (30–35 nm) formed during aging at 700 °C provide heterogeneous nucleation sites for the formation of intragranular B2 particles. Further aging at 450 °C promotes the precipitation of nano-sized κ′-carbides (5 nm) within the austenite matrix. The dual nanoparticles provide a significant precipitation strengthening contribution of 400 MPa without sacrificing ductility. The multiple deformation mechanisms of nanoscale “planar slip and Orowan bowing” provide an efficient source of work hardening capability. The present work aims to overcome the strength-ductility trade-off in austenitic lightweight steels by tailoring the precipitation process, which may provide insight into producing high-performance lightweight steels.

Ferroelectric properties and current mechanisms of BaTiO3/Nb:SrTiO3 thin films

[Formula: see text] thin film oxides have been deposited on [Formula: see text] substrates using a pulsed laser deposition system. Different annealing methods were thereafter used to assess the ferroelectricity of the grown films. The residual polarization value, 2Pr, of 4.205 [Formula: see text]C/cm2 and saturated residual polarization value, 2Pmax, of 15.484 [Formula: see text]C/cm2 were obtained using in-situ annealing. After performing rapid thermal annealing (RTA) annealing, the residual polarization value rose to 4.676 [Formula: see text]C/cm2 and the saturated residual polarization value rose to 18.723 [Formula: see text]C/cm2. Furthermore, a comparison of results showed that the saturation test frequency of the in-situ annealing was 10 times higher than the saturation test frequency of the RTA. This could be explained by the fact that the secondary high-temperature annealing led to a decrease in the conductivity of the doped oxide and, thereby, a decrease in the effective electric field that was applied to both ends of the BTO ([Formula: see text]) film. Thus, a lower frequency was required to ensure a flip of all ferroelectric domains within the BTO film. By testing the fatigue frequency at 100 kHz, [Formula: see text] stable cycles in both annealing methods and the results confirmed the good stability of the device performance. A linear fit analysis of the [Formula: see text] – [Formula: see text] curves showed under in-situ annealing the presence of both a bulk-limited current mechanism that was dominated by the space charge limited current (SCLC) and Pool–Frenkel (PF) mechanisms, and an interface-limited current that was dominated by the Fowler–Nordheim (FN) mechanism in the structure. After RTA annealing, the conducting mechanism is ohmic contact at low electric field and the SCLC mechanism at high field strength. The results show that after RTA annealing, the quality and ferroelectric properties of the films are significantly improved compared to those under in-situ annealing. These results showed that the BTO/NSTO/STO ([Formula: see text]) structure had a standard test frequency as well as reliable stability. The BTO/NSTO/STO structure showed, therefore, promising applications in future nonvolatile information memory devices.

Nanoscale study on the initial stages of the interdiffusion across the amorphous/crystalline interface of poly(methyl methacrylate)/poly(vinylidene fluoride) (PMMA/PVDF) via STEM plus EDX/EELS

Interdiffusion across the interface of poly(methyl methacrylate)/poly(vinylidene fluoride) (PMMA/PVDF) was investigated thoroughly by scanning transmission electron microscopy (STEM) plus electron energy-loss spectroscopy (EELS) and energy-dispersive X-ray spectrometry (EDX) and further with the assistance of laser-Raman spectroscopy. The factors of the annealing temperature and the time on the interfacial widths and the concentration profiles of PMMA and PVDF across the interface of PMMA/PVDF have been considered in detail. It was found that the concentration profiles of PMMA and PVDF were determined by the crystallization of PVDF, especially at the high annealing temperature (220 °C) in the PMMA part of the interface. Under the influence of the PVDF crystallization, the concentration profiles of F (from PVDF) and O (from PMMA) monitored by STEM-EDX/EELS changed gradually from parabola-shape to linear-shape in the PMMA part. The activation energy for the interdiffusion across the interface of PMMA/PVDF was calculated to be 51.0 kJ/mol, lower than the other reported pairs like poly(vinyl chloride)/poly(ε-caprolactone) (PVC/PCL) (69.8 kJ/mol) and poly(styrene-ran-acrylonitrile)/poly(methyl methacrylate) (SAN-29/PMMA) (175 ± 15 kJ/mol).

Improvements in Resistive and Capacitive Switching Behaviors in Ga2O3 Memristors via High-Temperature Annealing Process.

This study investigates the effect of a high-temperature annealing process on the characteristics and performance of a memristor based on a Ag/Ga2O3/Pt structure. Through X-ray diffraction analysis, successful phase conversion from amorphous Ga2O3 to β-Ga2O3 is confirmed, attributed to an increase in grain size and recrystallization induced by annealing. X-ray photoelectron spectroscopy analysis revealed a higher oxygen vacancy in annealed Ga2O3 thin films, which is crucial for conductive filament formation and charge transport in memristors. Films with abundant oxygen vacancies exhibit decreased set voltages and increased capacitance in a low-resistive state, enabling easy capacitance control depending on channel presence. In addition, an excellent memory device with a high on/off ratio can be implemented due to the reduction of leakage current due to recrystallization. Therefore, it is possible to manufacture a thin film suitable for a memristor by increasing the oxygen vacancy in the Ga2O3 film while improving the overall crystallinity through the annealing process. This study highlights the significance of annealing in modulating capacitance and high-resistive/low-resistive state properties of Ga2O3 memristors, contributing to optimizing device design and performance. This study underscores the significance of high-temperature annealing in improving the channel-switching characteristics of Ga2O3-based memristors, which is crucial for the development of low-power, high-efficiency memory device.

Highly active Mn2O3-Fe3O4 catalyst with abundant metal-oxygen bonds for real time sensing of carbendazim in environmental samples

In agriculture, a benzimidazole-based fungicide of carbendazim (CBZ) is widely used for disease control in fruits and vegetables. However, its toxicity raises concerns about potential harm to humans from consuming contaminated food. In this study, we developed an eco-friendly manganese iron oxide (Mn2O3-Fe3O4) catalyst via coprecipitation, employing with high temperature annealing (MFO-A) and calcination (MFO-C) techniques. Comparative physical and chemical characterization demonstrated that MFO-A performed better than MFO-C. The prepared catalyst was employed to modify a glassy carbon electrode (GCE) in order to enable electrochemical CBZ sensing through cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Under the optimized experimental condition, the sensor achieving a lower limit of detection (LOD), limit of quantification (LOQ), and sensitivity are 0.027 ng/L, 0.084 ng/L, and 1.57 µA (ng/L)–1 cm−2. The sensor demonstrated excellent selectivity, repeatability, reproducibility, and storage stability with acceptable recovery rate. The effectiveness of the present sensor was further validated through real-time analysis of environmental and food samples, highlighting its potential for enhancing environmental safety.

A Universal Self-Propagating Synthesis of Aluminum-Based Oxyhalide Solid-State Electrolytes.

Inorganic solid-state electrolytes (SSEs) play a vital role in high-energy all-solid-state batteries (ASSBs). However, the current method of SSE preparation usually involves high-energy mechanical ball milling and/or a high-temperature annealing process, which is not suitable for practical application. Here, a facile strategy is developed to realize the scalable synthesis of cost-effective aluminum-based oxyhalide SSEs, which involves a self-propagating method by the exothermic reaction of the raw materials. This strategy enables the synthesis of various aluminum-based oxyhalide SSEs with tunable components and high ionic conductivities (over 10-3 S cm-1 at 25 °C) for different cations (Li+, Na+, Ag+). It is elucidated that the amorphous matrix, which mainly consists of various oxidized chloroaluminate species that provide numerous sites for smooth ion migration, is actually the key factor for the achieved high conductivities. Benefit from their easy synthesis, low cost, and low weight, the aluminum-based oxyhalide SSEs synthesized by our approach could further promote practical application of high-energy-density ASSBs.

Phytic acid as an eco-friendly phosphorus source in the synthesis of phosphorus-doped NiCo2O4 for supercapacitor electrodes

This study explores the synthesis of nickel-cobalt bimetallic precursors using phytic acid (PA) as a phosphorus source and their application as supercapacitor electrodes. Through high-temperature annealing, these precursors were converted into phosphorus-doped nickel-cobalt bimetallic oxides (NCO) with certain defects. The morphologies and particle size of NCO can be easily adjusted by the amount of PA. Compared to the undoped nickel-cobalt bimetallic oxides, the phosphorus-doped materials exhibited significantly enhanced electrochemical activity and specific capacitance. The optimized electrode exhibits the highest specific capacitance of 1075 F·g−1 at a current density of 1 A·g−1. The asymmetric supercapacitor assembled together with activated carbon can deliver a relatively high energy density of 39.8 Wh·kg−1 at a power density of 696 W·kg−1. Additionally, this paper provides a detailed discussion on the impact of phosphorus doping on the performance of supercapacitor electrodes and the potential of PA as an eco-friendly phosphorus source in the synthesis of high-performance electrode materials.

Characterization of a HPHT boron ion-implanted diamond X-ray mirror following high vacuum annealing

The incorporation of boron into a diamond lattice holds the potential to advance X-ray optics, offering the capability to manipulate various parameters of the lattice. This includes enhancing near-infrared absorption relative to pure diamond, thereby enabling Q-switchable optics. The use of MeV boron implantation emerges as a promising method for precisely doping the diamond lattice. However, for these optics to function effectively as Bragg-reflecting mirrors, ion implantation must be executed with meticulous attention to maintaining a strain-free, perfect diamond lattice. This study aimed to investigate the feasibility of utilizing a 9 MeV ion beam for high energy boron implantation. Different areas of a high-pressure, high-temperature (HPHT) diamond sample were subjected to irradiation with 9 MeV Boron ions, ranging in fluences from 5×1015 to 2.5×1016ions/cm2. Following boron implantation, high-temperature vacuum annealing was performed to restore the diamond lattice. Our assessment utilized X-ray rocking curve imaging, surface profilometry, and micro-Raman spectroscopy, with additional observations on near-infrared transmission properties. Our measurement of high-quality Bragg reflection through X-ray rocking curve imaging, sensitive to implantation-induced strain and defects, served as an key diagnostic for the effectiveness of this ion-implanted sample as a Bragg-reflecting optic.

Bridging microscopic phase and defect manipulation with macroscopic core-sheath-shell structure for polarization-dominated electromagnetic wave absorption

Manipulating phases and defects brings boundless vitality to the design of electromagnetic wave (EMW) absorption (EMA) materials. However, current manipulations often prioritize the improvement in the overall EMA performance without distinguishing the effects of individual polarizations. Therefore, the design of EMA materials is result-oriented and limited by reliance on semi-empirical rules. Herein, we synthesized carbon cloth (CC)@MoS2@carbon nanotubes (CNTs) (CMSC) by self-assembly of MoS2 on CC, followed by in-situ growth of CNTs through high-temperature annealing. This synthesis process not only created a hierarchical core-sheath-shell structure consisting of an MoS2 intermediate sheath and a CNT outer shell but also introduced tunable vacancy defects and phases (2 H and 1 T). Density Functional Theory calculations revealed an enhanced carrier influx from the CNTs into the 2 H/1 T MoS2 due to the substantial difference in work function between the 1 T and 2 H phases, which promoted charge redistribution and subsequent polarization at defect sites and interfaces in CMSC. Therefore, defect-induced and interfacial polarizations dominated the EMW-attenuation mechanisms for CMSC, distinguishing it from CC@MoO2@CNTs, where conduction loss predominated. Owing to these enhanced polarizations and core-sheath-shell structure, CMSC exhibited a minimum reflection loss of −43.9 dB at 2.1 mm, even with a filler ratio of 3 wt%. This study highlights the potential for designing and tailoring polarization-dominated EMA materials through the manipulation of defects and phases.

Fabrication and Properties of Bi2S3 Nanowire Thin Film Solar Cells by Spin Coating with Varying Sulfur Concentrations in the Precursor

We conducted a simple solution-based method to fabricate Bi2S3 nanowire thin film solar cells by spin coating with varying sulfur-to-bismuth ratios. Spherical nanoparticles were observed in the thin film with low-concentration sulfur solution, with these nanoparticles gradually changing to nanorods. Finally, nanowires of Bi2S3 were observed in the thin film with a high sulfur concentration in solution. The band gap gradually decreased with the increase in sulfur concentration. The solar cell performance was significantly improved with the nanowire structure. During film fabrication, sulfur vacancy defects appeared primarily because of high annealing temperatures. These defects were somewhat reduced by the high concentration of sulfur in the solution, supported by the energy-dispersive x-ray spectroscopy (EDS) results. The elemental chemical composition of Bi2S3 material showed an increase in the sulfur-to-bismuth ratio, reaching saturation at almost 0.9. In this work, we systematically observed the effect on the optical properties, surface morphology, and photovoltaic properties by changing the concentration of sulfur in the precursor. The nanowire structure with a high concentration of sulfur in the solution is a promising way to improve the Bi2S3 thin film solar cell.

Photoluminescence studies of the charge states of nitrogen vacancy centers in diamond after arsenic ion implantation and subsequent annealing

In this work, nitrogen vacancy (NV) centers of high nitrogen diamond implanted with arsenic ions were investigated by photoluminescence spectroscopy. The transition of the NV center charge state was discussed by the regularly changing laser excitation power and measurement temperature following high-temperature annealing. After high-temperature annealing, the amorphous layer generated by arsenic ion implantation is transformed into a graphitization layer, resulting in a decrease in the NV yield. The electric neutral NV (NV0) center and negatively charged NV (NV−) center are affected by both radiation recombination and Auger recombination with increasing laser power. Accompanied by the increasing measurement temperature, the intensities of NV centers gradually decreased and eventually quenched. In addition, the charge states of NV− and NV0 centers were undergoing a transition. The zero phonon line positions of NV centers were also red shift, it was attributed to the dominant role of electron–phonon interaction in the temperature-dependent displacement of diamond energy gaps. The full width at half maxima of NV center were broadened significantly at higher temperatures.

Inkjet-printed boron-doped poly-Si/SiOx passivating contacts

In this study, we explore the utilization of inkjet printing technology with liquid ink to fabricate boron-doped polycrystalline silicon (poly-Si)/SiOx passivating contacts. The impacts of substrate morphology, baseplate temperature, and surface oxide on the printing performance were investigated to achieve distinct printed patterns. Moreover, a pre-oxidation process at 750 °C for 30 min was conducted as a strategy to prevent dopant spreading from the printed pattern via the gas phase during the high-temperature annealing. Thereafter, the influences of annealing temperature on the formed poly-Si passivating contact quality were studied. By applying optimized process conditions on intrinsic poly-Si(i-poly-Si)/SiOx/p-type crystalline Si (c-Si) substrates, promising surface passivation was achieved with an implied open-circuit voltage (iVoc) of 718 mV and a low contact resistivity (ρc) of 6.1 mΩ cm2 after annealing at 950 °C followed by a hydrogenation treatment. Optical images demonstrate that single-droplet dopant lines with a width of 69 μm could be realized on a mechanically polished substrate by printing with a drop spacing of 40 μm, while the line width expands on rough surfaces or when printing with a reduced drop spacing. Furthermore, high-resolution micro-photoluminescence maps clearly illustrate the localization of the boron-doped regions on polished and planar substrates after annealing. We also realized the formation of localized inkjet-printed phosphorus- and boron-doped poly-Si passivating contacts simultaneously within a single annealing step at 950 °C. These findings underscore the potential of inkjet printing as a promising technique for fabricating localized poly-Si/SiOx passivating contacts in high-efficiency silicon solar cells.

Enhancing the corrosion resistance of high Mo S31254 super austenitic stainless steel using grain boundary engineering

Super austenitic stainless steel (SASSs) with a high Mo content exhibit excellent resistance to intergranular corrosion (IGC), Its mechanical properties mainly depend on solid solution strengthening. Meanwhile, grain boundary engineering (GBE) can simultaneously improve the corrosion resistance and mechanical properties of Mo-rich austenitic stainless steel using the resistance to IGC of Mo. However, recrystallization annealing is extremely difficult due to the sensitive precipitation of Cr-rich and Mo-rich precipitations in SASSs. Therefore, this study explores the effect of large deformation, high temperature, and short-time annealing on the corrosion resistance of SASSs. The results show that a recrystallized organization with an average grain size of 13.3 μm was prepared by 50% cold rolling deformation and 2 min high-temperature short-time annealing at 1150 °C. The highest percentage of Σ3 GBs is about 34%, the percentage of other low-energy GBs is relatively low (only about 6%), and the rest are random high-angle grain boundaries (RHAGBs), which account for about 60%. It can be seen the corrosion resistance of random GBs after GBE treatment is superior to that of solution treatment. Meanwhile, medium-temperature aging improved the resistance to IGC of SASSs, especially after aging at 450 ℃, a small amount of Mo is enriched along the GBs, which promotes the formation of Cr2O3 and Mo-rich oxides in the passivation film and improves the corrosion resistance. The above results provide guidance for improving the corrosion resistance of Mo-rich austenitic stainless steels.

Fluorinated hole transport material resistant to high annealing temperature applied in inverted perovskites solar cells

A dopant-free and low-cost hole transport material (HTM) with dibenzo[b,d]thiophene as the center unit, bis(4-methoxyphenyl)amine as the terminal unit, and fluorine substitution adjacent to the methoxyl (named DBT-4F-MOP) is designed and applied in inverted organic-inorganic hybrid perovskite solar cells (OIH-PSCs). The synthetic cost of DBT-4F-MOP in the lab is just as low as 115 CNY/g, which is much lower than the benchmark HTM poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA, 2500 CNY/g). Due to the introduction of the fluorine atoms, the annealing temperature of the HTM can be increased by over 150 ℃. The highest efficiency of the inverted device based on it can reach 16.8 %, with an open circuit voltage of 1.04 V, a short circuit current of 21.57 mA cm−2, and a fill factor of 74.69 %, while the reference device based on PTAA can reach a PCE of 17.54 %. This work provides an avenue for the design of low-cost, dopant-free, and high-annealing temperature HTMs for inverted OIH-PSCs.

Enhancing the Responsiveness of Thermoelectric Gas Sensors with Boron-Doped and Thermally Annealed SiGe Thin Films via Low-Pressure Chemical Vapor Deposition.

Thermoelectric gas sensor (THGS) devices with catalysts and Si0.8Ge0.2 thin films of different boron doping levels of 1018, 1019, and 1020 cm-3 were fabricated, and their transport properties are investigated. SiGe films were deposited on Si3N4/SiO2 multilayers on Si substrates using low-pressure chemical vapor deposition (LPCVD) and thermally annealed at 1050 °C. The Seebeck coefficients of the SiGe films were increased after thermal annealing, ranging from 191 to 275 μV/K at temperatures of 74 to 468 °C in air, and reaching the highest power factor of 6.78 × 10-4 W/mK2 at 468 °C. The thermal conductivity of the SiGe films varied from 2.4 to 3.0 W/mK at 25 °C. The THGS detection performance was tested for the H2 gas in air from 0.01 to 1.0%, and compared to the thermoelectric properties of the SiGe films. The high-temperature annealing treatment process was successful in enhancing the thermoelectric performance of both the SiGe films and sensor devices, achieving the best THGS performance with the sensor device fabricated from the annealed SiGe film with 1018 cm-3 boron-doped Si0.8Ge0.2.