Box Furnace Research Articles

Boosting the photocatalytic performance of swiftly produced carbon nitride: Impact of cyano group and oxygen doping within the matrix

We present a significant advancement in the synthesis of carbon nitride framework (CN) using a rapid electric bunsen burner (EBB) method, achieving notable outcomes within a mere 10-min timeframe. The resulting material, designated as U10, exhibits amplified porosity and a semi-scrolling structure with a thickness measuring at 2.1 nm. In comparison to conventionally synthesized urea-derived carbon nitride (UCN) through a box furnace, the U10 demonstrates significantly heightened photocatalytic activity in both hydrogen (H2) production and the removal of organic dye (methylene blue) from aqueous solutions. To ensure the robustness and reliability of this synthetic approach, two additional precursors were subjected to testing, and their rates of H2 production were analyzed. The exceptional photocatalytic performance of the U10 material arises from its distinctive structural attributes and the synergistic influences of oxygen doping (O-doping) and the cyano (-CΞN) functional group, which are introduced during the rapid synthesis strategy. This innovative and streamlined strategy for synthesizing CN not only conserves energy and time but also significantly reduces production costs, rendering it a feasible method for the large-scale production of carbon nitride material.

Effect of rare earth element Y addition on the corrosion resistance of Cu-12.5Ni-5Sn alloy after aging

Cu-12.5Ni-5Sn-xY alloy with different rare earth Y contents was prepared by spark plasma sintering (SPS). The samples underwent aging at approximately 400°C for 4 hours in an energy-saving box furnace. The effect of trace Y addition on the microstructure and corrosion behavior of aging treated Cu-12.5Ni-5Sn-xY alloy were investigated by electrochemical test, and the corrosion mechanism of the alloy was discussed. The results indicated that the addition of rare earth Y improved the uniformity of microstructure and grain size of the alloy, and improved the corrosion resistance of the alloy. When the Y content changed between 0 wt% and 1.0 wt%, the corrosion resistance of the Cu-12.5Ni-5Sn-xY alloy gradually improved. The Cu-12.5Ni-5Sn-1.0Y alloy had a lower self-corrosion current density (1.490×10−5A/cm2) and a lower corrosion rate (0.178 mm/a). Compared to the Cu-12.5Ni-5Sn alloy without Y addition, the maximum corrosion depth was reduced by about 44.6 % and the corrosion resistance was improved. Rare earth Y promoted the uniform distribution of Ni elements, inhibited the conversion of Cu2O to Cu2(OH)3Cl, enhanced the layer density and stability. The internal corrosion layer mainly consisted of NiO, the intermediate layer mainly consisted of SnO, and the surface layer mainly comprised of CuO, Cu2O, and Cu2(OH)3Cl. Additionally, Y2O3 formed on the alloy's surface, effectively prevented corrosive ion attack and enhanced the corrosion resistance of Cu-12.5Ni-5Sn alloy.

Micro-Reducing Atmosphere with High-Rate Capability Performance of Carbon-Coated LiFePO4 Prepared from Spray-Drying-Assisted Solid-Phase Reaction

Nanostructured mesoporous LiFePO4/C (LFP/C) composite was prepared by spray-drying-assisted solid-state reaction with FeSO4 and LiOH as reactants. Instead of tubular furnace in various atmospheres (nitrogen or argon) of the calcination method, box furnace embedded with biomass waste rice husk char as embedded agent did not need to supplement atmosphere method was first applied in this study. The influence of micro-reducing atmosphere on the phase formation and particulate morphology of product was systematically investigated by XRD, SEM, TEM, XPS and Raman techniques. Rice husk char embedded was beneficial to the formation of LFP/C materials with good electrochemical performance and high stability. XRD and Raman test results show that pure LFP material can be prepared in the micro-reducing atmosphere, and the addition of glucose is conducive to the formation of crystallized carbon network. XPS of LFP/C materials demonstrate the micro-reducing atmosphere is conducive to the reduction of Fe3+ to Fe2+. Cathodes of LFP/C provided specific discharge capacities of 158 mA h/g and 128 mA h/g at 0.2 C and 10 C, respectively. The low cost spray-drying-assisted solid-phase reaction may be a practical way for the economic synthesis of LFP/C as high-rate electrodes of lithium-ion batteries.

Nitrogen-Rich Molybdenum Nitride Synthesized in a Crucible under Air.

The triple bond in N2 is significantly stronger than the double bond in O2, meaning that synthesizing nitrogen-rich nitrides typically requires activated nitrogen precursors, such as ammonia, plasma-cracked atomic nitrogen, or high-pressure N2. Here, we report a synthesis of nitrogen-rich nitrides under ambient pressure and atmosphere. Using Na2MoO4 and dicyandiamide precursors, we synthesized nitrogen-rich γ-Mo2N3 in an alumina crucible under an ambient atmosphere, heated in a box furnace between 500 and 600 °C. Byproducts of this metathesis reaction include volatile gases and solid Na(OCN), which can be washed away with water. X-ray diffraction and neutron diffraction showed Mo2N3 with a rock salt structure having cation vacancies, with no oxygen incorporation, in contrast to the more common nitrogen-poor rock salt Mo2N with anion vacancies. Moreover, an increase in temperature to 700 °C resulted in molybdenum oxynitride, Mo0.84N0.72O0.27. This work illustrates the potential for dicyandiamide as an ambient-temperature metathesis precursor for an increased effective nitrogen chemical potential under ambient conditions. The classical experimental setting often used for solid-state oxide synthesis, therefore, has the potential to expand the nitride chemistry.

The Influence of Rapid Tempering on the Mechanical and Microstructural Characteristics of 51CrV4 Steel

The microstructure and mechanical properties of a low-alloy medium carbon steel (Fe-0.5C-0.9Mn-1Cr-0.16V, in wt.%) were investigated after rapid tempering and compared with a conventionally tempered counterpart. The conventional thermal cycle was performed in a laboratory-scale box furnace while rapid heat treatments were carried out using the Gleeble 3800 thermomechanical simulator machine. In the rapid heat treatments, the heating rate was 50 °C/s for austenitizing and 60 °C/s for the tempering process, with a cooling rate of 60 °C/s for both treatments. Austenitization was performed at 900 °C for 3 s and tempering was conducted at 300 °C and 500 °C for 2 s. For conventional routes, the heating rate for both austenitization and tempering was 5 °C/s. Likewise, the austenitization was carried out at 900 °C for 45 min and tempering was carried out at 300 °C and 500 °C for 30 min. The results revealed that rapid tempering resulted in a significantly increased impact toughness compared to conventional tempering, while maintaining a consistent high strength level. The quenched samples showed the highest hardness and tensile strength but obtained the lowest toughness values. The optimum combination of strength and toughness was achieved with the sample rapidly tempered at 300 °C, resulting in a tensile strength of 2050 MPa and impact energy of 14 J for sub-sized CVN samples. These desirable mechanical properties were achieved throughout the tempered martensitic microstructure with a minor fraction of pearlitic strings.

Hot corrosion behavior of CYSZ thermal barrier coating with optimized laser surface modification

The current study aims to investigate the influence of laser surface modification on the hot corrosion, fracture toughness, and hardness resistance of atmospheric plasma sprayed Ceria-Yttria Stabilized Zirconia (CYSZ) thermal barrier coating. Throughout the laser surface modification process, a variety of laser processing parameters are used to obtain the finest surface properties and optimum laser parameters. In this study, the whole coating surface is modified using the optimal parameters. The results show that 52.9 W laser power at a 220 mm laser distance and a 60 mm/s scanning speed were found as the optimum laser glazing parameters. A hot corrosion test is performed in a box furnace for 20 h at 1050 °C. Scanning electron microscopy (SEM) images show denser surfaces in laser-glazed coatings when compared to air-spraying coatings. A dense microstructure combined with the top coat is created in the coating cross-section, and a smooth microstructure with a coaxial fracture network is produced on the surface. The laser-glazed layer has superior mechanical characteristics to the as-sprayed coating, including hardness and fracture toughness. This layer also restricts the damaging monoclinic-tetragonal phase change for CYSZ TBC, blocking the infiltration of molten salt. The hot corrosion behavior of TBCs is improved by the inclusion of a dense laser-glazed layer.

Influence of oxide based reinforcements in oxide-oxide ceramic matrix composites (CMCs)

In comparison to other processes, powder metallurgy processing of alumina-based ceramic matrix composites (CMC) is considered a viable option. In this study, Alumina ceramic composites are developed by adding MgO, TiO2, and Fe2O3 as reinforcement particles. Reinforcement particles were added to the Alumina matrix at 0.25%, 0.5%, and 1.0% by weight. Each reinforcement is added individually to the matrix by varying percentages. Alumina with reinforcement is mixed properly using hand grinding. Blended powders were compacted using a hydraulic press to form the green compact. Green compacted samples were preheated and sintered in a box furnace at a temperature at 1600 °C for 5 h. Mechanical properties of the sintered samples taken into consideration such as density, Vickers hardness, fracture toughness and porosity level have been measured. SEM images of the samples were carried out to understand the reinforcement presence in the matrix. It is observed that the highest bulk density (3.881 g/cm3) was obtained for alumina samples when reinforced with 0.5% TiO2. The minimum porosity level was found to be 0.199% when alumina was reinforced with 1% Fe2O3. The highest Vickers microhardness value was obtained to be 41.96GPa for 0.25% of the Fe2O3 reinforced alumina sample. Alumina with 0.5% MgO reinforcement has the highest fracture toughness of 8.98 MPa/m1/2.

A novel method for experiments in a one-atmosphere box furnace

Abstract We present a conceptually simple method to perform high-temperature experiments in a one-atmosphere box furnace that has a negligible cost of materials. The experimental setup consists of two commercially available materials and can be customized to sample or furnace size with few limitations. Furthermore, the design allows easy extraction of samples in one piece, making them eligible for textural analysis. The setup comprises a graphite capsule and a fireclay shell, the latter of which acts as a heat-resistant protective shield. Containers must be individually hand-crafted, but each can hold multiple samples. The setup can be reliably used in temperature conditions below the heat tolerance limit of the commercial fireclay, commonly ~1400 °C. Moreover, the graphite capsule buffers the oxygen fugacity to strongly reducing conditions during the experiment. The main advantage of our method lies in the utilization of easily accessible and low-cost materials that provides a widely applicable experimental setup easily used at larger scales. The method was developed during an experimental study of magmatic crystal-liquid suspensions and was reliable for experiments lasting for up to 36 h.

Hot corrosion and CMAS degradation of laser-glazed YSZ coating with optimum parameter

The purpose of this research is to look into the effect of laser surface modification on the hot corrosion and hot corrosion + calcium–magnesium aluminosilicate (CMAS) resistance of YSZ thermal barrier coating. Metco AMDRY 997 (Ni–22Cr–10Al–Y) powder was coated as a bond coat on the AISI 304L stainless steel substrate using a high-velocity oxy-fuel spray technique. As a ceramic top layer, 204 NS YSZ (ZrO2·8Y2O3) particles were plasma sprayed on the bond coat. Following that, the entire coating surface was treated with a 20-kHz pulsed CO2 laser to increase the coatings’ surface performance. A corrosion test was carried out in a box furnace for 20 h at 1050 °C. SEM images of laser-glazed coatings revealed denser surfaces than those of air-spraying coatings. The laser-modified coating is more resistant to hot corrosion than unmodified coatings. The X-ray diffraction analysis revealed that the reaction between yttria (Y2O3) and V2O5 resulted in the formation of YVO4 crystals as a corrosion product. According to energy dispersive spectroscopy results, laser-glazed coatings reduced molten salt diffusion from surface to bond coat. As a result, laser-glazed coatings demonstrated improved hot corrosion resistance and decreased corrosion products on the bond coat zone. After the hot corrosion test, the laser-treated composite had a 55% lower thermally grown oxide layer than untreated APS YSZ. The optimum laser parameter was used as 77.7 W laser power, 120 mm/s scanning speed, and 215 mm laser distance.

Nanoarchitectonics Pt/NiCo in a carbon matrix as highly efficient electrocatalyst for hydrogen evolution reaction

Alkaline electrocatalysts for hydrogen evolution reaction (HER) are important for applications requiring long lifetime and strong catalytic activity. We have successfully synthesized Pt/NiCo@C nanoarchitectonics by a simple solvothermal approach using a box furnace. To develop the carbon matrix on the metal surface, trimesic acid was used as a carbon source at a high temperature of 750 °C in an N2 gas atmosphere. The electrical structure of the Pt-based alloy was significantly changed by the carbon matrix, which also improved the electron transport and electrocatalytic activity. In particular, the Pt/NiCo@C alloy demonstrated excellent HER performance in a 1.0 M KOH electrolyte, with a low overpotential of 48 mV required to achieve 10 mA cm−2 current density. In addition, it showed a fast kinetic response of 130 mV dec−1 when the Tafel slope was calculated. Importantly, the Pt/NiCo@C alloy demonstrated remarkable durability, with a minimum voltage loss at 10 mA cm−2 constant current density for up to 25 h of chronopotential run. This work provides some useful guidance for the synthesis of multimetal catalysts for electrochemical energy conversion.

The Coating Effect on Interconnect Materials After >10 Years of Furnace Exposures

The present work has studied the effect of subjecting an AISI 441 ferritic stainless steel in a box furnace exposure in air at 800 °C for up to 10 years. During operation, the mass gain was repeatedly measured at selected time intervals. The results show that there are only small differences in spinel composition when a sample exposed for ~5 years is compared to a sample exposed for 10 years, with the main difference being a growth of the chromia scale from ~10 to ~14 µm. In addition, the chromium content is 12.3 wt-% after 5 years whereafter it is further reduced to 10.5 wt-% during the following exposure time. Despite a relatively low chromium content already after 5 years, there are no visible signs of material failure, e.g, neither spallation nor a a large increase in mass gain during the 10 years in the furnace.

Design and development of type-1 FBG based high temperature sensor

Thermal metrology is critical in many high-energy industrial processes to optimize the process efficiency, energy consumption and quality of end product. Here, we present the design and development of a double thimble type standard type-1 fiber Bragg grating (FBG) high temperature sensing probes. Two different probes named probe-1 and probe-2 are developed by encapsulating type-1 FBGs in two stainless steel thimbles with ceramic filling. The probes are experimentally tested in a high temperature box furnace and their responses are interrogated by an optical spectrum analyzer. FBGs encapsulated in both probe-1 and probe-2 exhibited a linear red-shift in their Bragg wavelength with increase in temperature from 30 °C to 700 °C with sensitivities of 13.86 ± 0.1 pm/°C and 14.10 ± 0.2 pm/°C which are 4.8% and 3.16% lower than temperature sensitivity of bare FBG, respectively. A deformation in the Bragg spectrum of probe-1 is observed at temperatures above 500 °C however, probe-2 is found to be thermally stable up to 700 °C. An estimated life-time of about 6 years is offered by the optimized probe-2 with a negligible hysteresis and repeatability of 1°C–5°C.

Color change in teeth due to burning: Spectrophotometric analysis

Teeth are one of the most common skeletal elements for forensic identification purposes and also the strongest human tissue, making them resistant to high temperatures. Over the course of burning as temperature increases, teeth go through a process of structural change characterized by a carbonization phase (at approx. 400 °C) and calcination phase (at approx. 700 °C) that might result in complete enamel loss. The aim of the study was to quantify color change of enamel and dentin and to determine whether both tissues can be used for estimating burn temperature as well as to evaluate the whether these changes are visually perceptible. 58 human, permanent maxillary molars without restorations were burned for 60 min at either 400 °C or 700 °C in a Cole-Parmer StableTemp Box Furnace. The change in color was measured for the crown and root using a SpectroShade Micro II spectrophotometer to determine lightness (L*), green-red color (a*), and blue-yellow color (b*). Statistical analysis was performed using SPSS version 22. There is a significant difference between the L*, a*, and b* values of pre-burned enamel and dentin at 400 °C (p < 0.001). In addition, differences in dentin measures between 400 °C and 700 °C (p < 0.001), as well as pre-burned teeth and 700 °C (p < 0.001). The mean L*a*b* values were used to calculate a measure of the perceptible difference between colors (ΔE) revealing a highly perceptible color difference between the pre- and post-burn teeth for both enamel and dentin. There is a low perceptible difference between burned enamel and dentin was found. During the carbonization phase the tooth gets darker and redder and as temperature increases, teeth become bluer. Overall, as calcination occurs the tooth root color gets closer to a neutral gray palette. The results showed a highly perceptible difference indicating that for forensic purposes simple visual color evaluation can provide reliable information, and dentin color evaluation can be used in cases when enamel is missing. However, the spectrophotometer allows an accurate replicable measure of tooth color across various stages of the burning process. This has practical applications in forensic anthropology as a portable and nondestructive technique that can be used in the field regardless of the practitioner’s level of experience.

Oxidation response of ZrB2–SiC–ZrC composites prepared by spark plasma sintering

Considering the importance and application of ultrahigh temperature ceramics in oxidizing environments, in this research, the effect of ZrC content and spark plasma sintering parameters (temperature, time and pressure) on the oxidation response of ZrB2–SiC composites has been investigated. After fabricating the ternary composite samples in different SPS conditions and with different amounts of ZrC, the post-sintering oxidation process was carried out in a box furnace at the temperature of 1400 °C. Increasing the time and temperature of the SPS process caused the decrease in the oxidation resistance of the samples. The reason for such observations was attributed to the extreme growth of grains with increasing the temperature and time of the sintering process despite the better densification of the samples. This research did not reach a clear result about the effect of SPS pressure on composites oxidation behavior. Increasing the amount of ZrC also did not have a positive effect on the oxidation resistance of the samples because this phase itself undergoes oxidation at low temperatures.

Oxidation of Hafnium Diboride—Silicon Carbide at 1500 °C in Air; Effect of Compressive Stress

The long-term oxidation behavior of HfB2 and of HfB2-20 vol.% SiC was studied. Test samples of each material were oxidized at 1500 °C in air using a box furnace. The exposure times were 0, 0.5, 1, 2, 3, 6, 9, 12, 15, 30, 45 and 90 h. Weight gain, oxide scale composition and oxide scale thickness were characterized for both materials. Crystal structure of the surface scales was analyzed using x-ray diffraction. Oxide scales were further characterized via scanning electron microscopy with energy dispersive spectroscopy analysis. For HfB2 the oxide scale consists predominantly of porous HfO2. For HfB2-20 vol.% SiC, the oxide scale is composed of a borosilicate glass outer layer and a porous HfO2 layer. Weight gain and the growth of oxide scale with exposure time were measured. The oxidation kinetics were determined using the weight gain as well as the scale thickness measurements, and the parabolic rate constants were calculated for both materials. The addition of SiC dramatically inhibited the oxidation of HfB2. The effects of compressive stress on oxidation of HfB2-20 vol.% SiC were also examined. Samples were oxidized while being subjected to compressive stress of 50-150 MPa for up to 30 h at 1500 °C in air. Compressive stress was found to have little effect on the growth of oxide scale with time. The oxidation data were analyzed in terms of mechanistic models for the oxidation of monolithic and SiC-containing refractory diborides. For HfB2-20 vol.% SiC, the model predictions agreed well with experimental data. For HfB2, the model significantly under-predicted the scale thickness, but accounted for weight gain reasonably well except for the longest exposure time of 90 h.

Green synthesis and characterization of UKMRC-8 rice husk-derived mesoporous silica nanoparticle for agricultural application

Agriculture plays a crucial role in safeguarding food security, more so as the world population increases gradually. A productive agricultural system is supported by seed, soil, fertiliser and good management practices. Food productivity directly correlates to the generation of solid wastes and utilization of agrochemicals, both of which negatively impact the environment. The rice and paddy industry significantly adds to the growing menace of waste management. In low and middle-income countries, rice husk (RH) is an underutilized agro-waste discarded in landfills or burned in-situ. RH holds enormous potential in the development of value-added nanomaterials for agricultural applications. In this study, a simple and inexpensive sol–gel method is described to extract mesoporous silica nanoparticles (MSNs) from UKMRC8 RH using the bottom-up approach. RHs treated with hydrochloric acid were calcinated to obtain rice husk ash (RHA) with high silica purity (> 98% wt), as determined by the X-ray fluorescence analysis (XRF). Calcination at 650 °C for four hours in a box furnace yielded RHA that was devoid of metal impurities and organic matter. The X-ray diffraction pattern showed a broad peak at 2θ≈20–22 °C and was free from any other sharp peaks, indicating the amorphous property of the RHA. Scanning electron micrographs (SEM) showed clusters of spherically shaped uniform aggregates of silica nanoparticles (NPs) while transmission electron microscopy analysis indicated an average particle size of < 20 nm. Besides Energy Dispersive X-Ray which validated the chemical constituent of the silica NPs, the Fourier transform infrared (FT-IR) spectra showed peaks at 796.4 cm−1 and 1052 cm−1 corresponding to O–Si–O symmetric stretching vibration and O–Si–O asymmetric stretching, respectively. The Brunauer–Emmet–Teller (BET) analysis indicated an average pore size = 8.5 nm while the specific surface area and the pore volume were 300.2015 m2/g and 0.659078 cm3/g, respectively. In conclusion, agrowaste-derived MSN was synthesized using a simple and economical sol–gel method without the addition of surfactant reagents for controlled formation at the structural level. Owing to the MSNs’ excellent physical properties, the method established herein, could be used singly (without any modifications) for the functionalization of a myriad of agrochemicals.

Milligrams to Kilograms - Scaling Production of Cobalt Free Lithium Excess Cathode Materials through Rotary Calcination

Both Tesla and the Government of the United States have listed the elimination of cobalt and the resilience of the battery cathode supply chain as critical issues in need of advancement 1,2. This investigation answered this call to action through scaling the production of a high-performance cobalt free lithium excess cathode material using rotary calcination. The cathode in this investigation is of the chemical series Li[NixLi(1/3-2x/3)Mn(2/3-x/3)]O2 (where x = 0.25), and to our knowledge this marks the first time an investigation has demonstrated the scaling of this class of materials. In order to achieve the several orders of magnitude increase in production scale the precursor feedstock for rotary calcination required comparison of sol-gel, Pechini, and solid-state precursors routes. Viability of each precursor synthesis route required comparison of synthesis time, synthesis complexity, Thermogravimetric Analysis, Dynamic Scanning Calorimetry, X-Ray Diffraction of intermediate and final materials, as well as Galvanostatic cycling of final cathode materials. Modification and controlled decomposition of sol-gel processing was ultimately used for the scaled production of precursor powders. Once the precursor feedstocks were fed through the rotary kiln we used X-Ray Diffraction, X-Ray Fluorescence, Galvanostatic Testing, and Scanning Electron Microscopy of resultant materials to optimize rotary calcination conditions to find the pareto optimal conditions that allowed for maximized material quality, and output, with minimized energy and time costs. These materials were also compared to our baseline material, which was made in a box furnace in ambient conditions over the course of 24 hours. Synthesis conditions were also modified to allow for the inclusion rapid water quenching of final scaled material to ensure material quality.Sources: F. C. for A. Batteries, National blueprint for lithium batteries 2021–2030, (2021).E. Musk and R. Denholm, UPDATES TO 2020 ANNUAL MEETING OF STOCKHOLDERS AND BATTERY DAY EVENT, (2020).

Optimum temperature, time and atmosphere of precursor pyrolysis for synthesis of B4C ceramics

In this paper, the variables of the pyrolysis operation such as temperature, time, and atmosphere were studied and optimized. At first, the effect of increasing pyrolysis time at lower temperatures was investigated to understand the mutual influence of pyrolysis time and temperature in enhancing the efficiency of B4C synthesis. Then, three pyrolysis atmospheres were selected to find the optimal conditions: burial method in box furnace (air), pyrolysis in tubular furnace (argon), and pyrolysis in box furnace (air). The pyrolyzed powders were finally located inside the tubular furnace at 1500 °C for 4 h under argon atmosphere to synthesize B4C ceramics. X-ray diffractometry (XRD) was employed to determine the optimal processing conditions. The temperature of 600 °C and the holding time of 2 h were selected as the optimal pyrolysis conditions. Meanwhile, the burial method was chosen as the best atmosphere despite having a higher percentage of impurity because of the much lower cost compared to the argon atmosphere.

The Potential Effect of Annealing Mesostructured Titanium Dioxide Electrode in a Closed Box Furnace on the Concentration of Lead (II) Iodide Solution Required for Optimal Performance of Mesoscopic Perovskite Solar Cells

Highly reproducible mesoscopic perovskite solar cells (PSCs) can be fabricated using two-step sequential deposition of organo-lead halide (perovskite) active layer. However, differences in the processing conditions of individual layers which are subsequently assembled to construct the ultimate device can result in variations in the solar cell performance. For instance, here we report trends in the device performance as a function of PbI2 solution concentration, where the compact and mesoporous TiO2 layers were annealed in a closed box furnace (instead of doing it in open air). We observed that the devices prepared using 1.2 M PbI2 solution concentration performed better than those prepared from 0.8 M and 1 M PbI2 solutions. Generally, the researchers use the hot plate in an open-air environment or use a special hot plate where a continuous flow of air is ensured while annealing TiO2 electron selective layers (ESL) for perovskite solar cells. In this case, the highest possible device efficiencies are achieved using 1 M concentration of PbI2 solution. Although the influence of PbI2 solution concentration has been previously studied in detail, here our prime focus is to briefly comment on slight differences in the device performance trends which we observed in comparison to the previously reported results, where TiO2 layers were calcined in open air.

Growth of Pure and Intercalated Zrte2, Tite2 and Hfte2 Dichalcogenide Single Crystals by Isothermal Chemical Vapor Transport

We report on a modified chemical vapor transport (CVT) methodology for the growth of pure and intercalated Zr, Ti, and Hf dichalcogenide single crystals, e.g. ZrTe2, Gd0.05ZrTe2, HfTe2, and Cu0.05TiTe2. While the most common method for CVT growth is carried out in quartz tubes subjected to a temperature gradient between the charge and the growth location, the growth using this isothermal-CVT (ICVT) method takes place isothermally in sealed quartz tubes placed horizontally in box furnaces, using iodine (I2) as the transport agent. The structure and composition of crystals were determined by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and induced coupling plasma (ICP). The crystals grown with this method can be large, and show excellent crystallinity and homogeneity. Their morphology is plate-like, and the larger dimensions can be as long as 15 mm.