Search

This research explores a segment of the mechanical, thermal & physical characteristics of a polymer polypropylene (PP) mixture including low density polyethylene (LDPE). There were mixing syntheses (pure PP, 25 LDPE/75PP, 50LDPE/50PP, 75LDPE/25LDPE, pure PP) that were examined. As outcome, the expansion of LDPE to PP has decreased, with improved thickness, elasticity, bending efficiency, versatile modulus and hardness. In a (25LDPE/75PP) arrangement the prevailing elasticity was achieved while the (50LDPE/50PP) synthesis was attributed to ideal bent efficiency. High density polyethylene (HDPE) blowing in different proportions PP/polyethylene (PEs) can remove sorting course employed during even recycling course. PP has interesting features like outstanding process ability &tolerance to chemicals. Inadequate versatility, however, limits its usage in specific applications. Mixing PP with relative PEs may enhance its versatility. Universal kinetics of PP crystallization have been affected greatly by the existence of PEs of various structures of the ramifications. Existence of LDPE reduced overall summation ratio while HDPE increased the process of crystallization. No negative effect was observed in the studied parameter range on mechanical performance and the related crystallinity.

For the medical diagnosis, radiopaque materials (RM) made from high specific gravity elements like Pt, Au, Ta, Iodine, Bromine are either attached or blended or coated on an implant to makes it detectable under X-ray/Fluoroscopy/CT-Scan. RM facilitate the surgeon in an operation theatre to position an implant during the surgery. Mainly, RM are non-degradable, thus in case of biodegradable implants, it may detach from the body and accumulate in vital organ cause serious health issue. Therefore, a new bioresorbable radiopaque material (BRM) was produced by alloying the high specific gravity elements Zn (35% w/w) and Y(4% w/w) with Mg metal. In this alloy, three main phases were identified, alpha Mg, Mg7Zn3 and icosahedral quasicrystalline I-phase Mg3Zn6Y, which reinforce the Mg matrix. Hereafter, BRM was powdered to a size of less than 25microns and blended in different ratios with bioresorbable poly- l -lactic acid (PLLA) for fabricating PLLA/BRM bio-composite. BRM microparticles were uniformly distributed and interfacial bonded with the matrix. The X-ray was passed through bio-composite to capture µCT radiograph for evaluating linear attenuation co-efficient (µ) and optical density (OD). Thermal analysis reveals that BRM particles act as a nucleating site and enhance the crystallinity of the polymeric chain. During the In Vitro accelerated degradation study, the alkaline nature of BRM neutralise the acidity of PLLA and balance the pH of the body fluid to reduce the inflammatory reactions, but this compromises the stability of the polymer as it increases the decomposition rate.

In this study, the Ti/SnO2-RuO2 electrodes with different Yb contents were prepared by sol-gel method and thermal decomposition method, and the surface morphology and crystal structure of the electrodes were characterized by scanning electron microscopy (SEM), atomic force microscope (AFM) and X-ray diffraction (XRD), the electrochemical properties of the electrodes were tested by linear sweep voltammetry (LSV) and cyclic voltammetry (CV). The electrochemical oxidation device was constructed with Yb-doped Ti/SnO2-RuO2 electrode as the anode and titanium plate as the cathode, and the electrochemical oxidation effect and product changes of the anode on coking wastewater were investigated. The results show that the surface of the electrode is flat with high crystallinity of SnO2 and RuO2 crystals at 1.5% Yb doping, and the LSV and CV curves indicate that the rare earth doping of 1.5% increases the oxygen precipitation potential and electrocatalytic oxidation activity of the electrode. When the electrode with rare earth doping of 1.5% is the anode with current density of 10mA/cm2 electrochemical oxidation time of 30min, the electrode can remove COD up to 85.06%, TOC up to 60.59% and UV254 from 1.594 to 0.507 for coking wastewater. GC-MS, UV-vis and three-dimensional fluorescence results of coking wastewater before and after treatment show that large toxic substances in coking wastewater are degraded to low toxic organic substances, and most soluble organic substances are degraded and transformed. This study provides the possibility of basic research for the engineering practice of electrochemical oxidation for the treatment of coking wastewater.

SrLi2Ti6O14 (SLTO) coated with different amount of ZrO2 was successfully prepared. The as-obtained composites are stacked by a series of particles with a pure phase structure and a good crystallinity. Furthermore, ZrO2 coating not only enhances the structural stability of the materials but also facilitates the diffusion of lithium through the SEI film. As a result, the redox polarization was reduced, and the reversibility of the electrochemical reaction was enhanced. Particularly, SLTO-ZrO2-2 sample delivers a high initial lithiation capacity of 283.6 mA h g−1, and the values maintain at 251.7, 228.0, 207.4, 175.3, and 147.7 mA h g−1 at the current densities of 0.13, 0.26, 0.54, 1.31, and 2.62 A g−1, respectively. Our experiment also confirmed that SLTO materials coated with ZrO2 are suitable for high power density applications, and the lithiation specific energy efficiency of SLTO-ZrO2-2 is 200% as high as that of pure SLTO at a power density of 1257 W kg−1.

Hydroxyapatite (HAP), which is chemically represented as (Ca10(PO4)6(OH)2), is one of the main inorganic material of vertebrate bone and teeth. The bioceramic material is used as a substitute for deficient bone tissue because of its similarities to crystallographic and chemical composition of teeth and bone. HAP is extensively used in various biomedical applications because of its excellent properties, such as bioactivity, non-toxicity, biocompatibility, non-immunogenicity and osteoconductivity. In this work, hydroxyapatite powder was synthesized using polyoxyethylene lauryl ether (Briji-35) as a surfactant and dimethyl sulfoxide as a primary surfactant through microemulsion method. The obtained products were characterized by FTIR, XRD and SEM. The result indicated that, the Briji-35 played an important role for the formation of nano-hydroxyapatite particle with good crystallinity and particles with uniform morphology besides controlling the particle size of nano-HAP. The biomedical application studies of the as-synthesised material are yet to be studied.

Owing to their high surface area, stable structure and easy fabrication, composite nanomaterials with encapsulation structures have attracted considerable research interest as sensing materials to detect volatile organic compounds. Herein, a hydrothermal route is designed to prepare foam shaped α-MoO3@SnS2 nanosheets that exhibit excellent sensing performance for triethylamine (TEA). The developed sensor, based on α-MoO3@SnS2 nanosheets, displays a high response of 114.9 for 100 ppm TEA at a low working temperature of 175 °C with sensitivity higher than many other reported sensors. In addition, the device shows a wide concentration detection range (from 500 ppb to 500 ppm), good stability after exposure to air for 80 days, and excellent selectivity. The superior sensing characteristics of the developed sensor are attributed to the high crystallinity of α-MoO3/SnS2, excessive and accessible active sites provided by the good permeability of porous SnS2 shells, and the excellent conductivity of the encapsulation heterojunction structure. Thus, the foam shaped α-MoO3@SnS2 nanosheets presented herein have promising practical applications in TEA gas sensing devices.

The aim of the present work is to investigate the influence of Samarium ions doping in the TiO2 host lattice and the contribution to the optical properties of this semiconductor. The X-ray diffraction pattern shows the formation of anatase phase TiO2 nanoparticles of average sizes 7.8 nm, 7.21 nm and 6.1 nm for both pure and 1 wt% and 4 wt% of Sm3+ doped samples respectivity. Energy Dispersive X-ray (EDX) spectroscopy confirms the presence of Sm ions within the Sm substituted TiO2 nanoparticles. These results suggest that, Pure and doped TiO2 samples confirm anatase phase of good crystallinity with smaller crystallite size. UV–visible spectra display stronger absorption in the visible region. The photocatalytic experiments are investigated by the removal of rhodamine B under UV light. Compared to the other two photocatalysts, the results shows that 4 wt% of Sm3+ doped TiO2 exposes the highest photocatalytic performance.

Solid materials that do not present a perfect crystalline structure at long range are called polycrystalline materials. This deviation from a perfect crystallinity is known as the microstructure and determines the properties of materials. The microstructure can be studied by the analysis of X-ray diffraction patterns, which is known as X-ray line profile analysis (XLPA). The peaks in the diffractogram can broaden due to crystallite size, density of dislocations, planar defects, chemical heterogeneities, and surface relaxation. This allows the analysis of the microstructure via XLPA. Here, a review of the methods developed for XLPA analysis is presented. From the classical methods of Williamson-Hall and Warren-Averbach, to their modified versions and modern analysis methods are briefly described, as well as their scope and limitations. The conclusions present the area of opportunity of XLPA in polycrystalline solids today, as well as potential applications in materials science.

Hydroxyapatite (HAP) [Ca10(PO4)6(OH)2] is an excellent bio-ceramic material for artificial bone substitution in biomedical field owing to its chemical and crystallographic similarities of natural bone and teeth. In this research work, we have attempted the synthesis of hydroxyapatite powders with controllable size in the presence of three different surfactants sodium dodecyl sulphate (SDS) which is an anionic surfactant, cetyl trimethylammonium bromide (CTAB) as a cationic surfactant and poly vinyl alcohol (PVA) as a non-ionic surfactant. The as-synthesised HAP powders were characterised by analytical techniques such as FTIR, XRD and SEM. The results have shown that the non-ionic surfactant is a better choice for developing this bio-nanomaterial due to its good dispersing power than CTAB and SDS. The results have also indicated that, nano-hydroxyapatite particle has a uniform morphology, well crystallinity and the particle size was controlled with the use of non-ionic surfactant. The crystallite size was calculated using Scherer’s formula. Experiments were performed under controlled environment by maintaining the required pH, concentration and temperature. The biomedical application studies of the as-synthesised material are yet to be studied.

PVA-NaI based composite electrolyte has been synthesized using the solution casting method. The prepared composite was characterized by electrical and structural properties. Conductivity measurement of the composite was done using Complex Impedance Spectroscopy. The maximum conducting sample was further studied for its structural properties using X-Ray Diffraction. Perfect complexation between PVA and salt NaI was evaluated using Fourier transform Infrared Spectroscopy. Crystallinity or amorphicity of the maximum conducting sample was studied using X-Ray diffraction. The maximum conducting sample was used as a humidity sensor and surface properties were observed through Scanning Electron Microscopy.

Optically transparent L-Proline Adipate (LPA) single crystal has synthesis by slow evaporation solution growth technique (SEST) method at ambient condition. The crystallinity of LPA crystal was examined by powder XRD analysis, which crystallizes in the monoclinic system. The various functional groups were identified by FTIR spectra and it compares with a simulated spectrum of LPA by using DFT/B3LYP 6–311++G(d,p) set. The Photoluminence spectrum (PL) was used to determine the optical properties of LPA. The Vickers microhardness measurements reveal the crystal possesses soft category of mechanical strength. The determined HOMO-LUMO value shows the crystal is chemically active and charge transfer occurs within the molecule. The linear polarizability (α) and 1st order hyperpolarizability (β) values of LPA have been investigated.

The stability issue has become one of the main challenges for the commercialization of perovskite solar cells (PSCs). Formamidinium (FA)-based perovskites have shown great promise owing to their improved thermal and moisture stability. However, these perovskites are suffering from phase transition and separation. Here, a method of incorporating of γ-aminobutyric acid (GABA) and cesium cations into FAPbI3 is developed to improve the phase stability. It is demonstrated that the crystallinity of α-FAPbI3 phase is greatly improved and the phase transition temperature is significantly dropped. The resultant solar cell therefore obtains a champion power conversion efficiency (PCE) of 23.71%, which is one of the highest efficiencies for methylammonium-free PSCs. Furthermore, it shows an impressively enhanced stability under illumination, exhibiting the great potential of FA-based perovskites for efficient and stable solar cells.

This paper reports the physical properties of magnesium ion (Mg2+) conducting biopolymer electrolyte films of cellulose acetate (CA) + xwt.% Mg(ClO4)2 containing different amounts of magnesium salt (x = 10, 20, 30, 40 and 50 wt%) which have been prepared by the solution cast technique. The prepared biopolymer films were characterised by XRD, FTIR, DSC and UV–vis spectroscopy. The structural analysis carried out by X-ray diffraction (XRD) study confirms the structural changes & decrease in the degree of crystallinity of the host biopolymer matrix CA upon incorporation of magnesium salts Mg(ClO4)2. And this effect is more pronounced at higher loading. The DSC thermograms of the electrolyte films showed that the glass transition temperature (Tg) increases with the increase of salt content in the biopolymer CA matrix which is attributed to the restriction in the mobility of the polymeric chains. This hindrance was caused by the high density constituent ions of dopant salt. Fourier transform infrared (FTIR) spectroscopic study confirms the complexation between the cations of the dopant salt (Mg2+) and ester group (i.e. C = O) of the biopolymer chain owing to Lewis acid-base interactions. The UV–visible spectroscopic analysis demonstreted that optical absorption edge as well as direct & indirect optical band gap decreases with the incease of the concentration of dopant magnesium salt.

The high degree of crystallinity of discharging intermediates of Li-S batteries (Li2S2/Li2S) causes a severe capacity attenuation at low temperatures. Herein, a sulfur-rich polymer is fabricated, which enables all the discharging intermediates to exist in an amorphous state without long-range order, promoting the substantial conversion of discharging intermediates and enhancing Li-S batteries' performance at low temperatures greatly. This cathode material exhibits excellent performance both at room and low temperatures. Even under an extremely low temperature (–40 ℃), the discharge capacity can remain 67% of that at room temperature. Besides, in-situ UV/Vis spectroscopy and density functional theory calculations reveal that this organosulfur cathode undergoes a new mechanism during discharge. Li2S6 and Li2S3 are the primary discharging intermediates that are quite different from conventional Li-S batteries. These results provide a new direction for a broader range of applications of Li-S batteries.

This paper presents synthesis and study of Structural, Optical, and Photocatalytic properties of bismuth ferrite (BFO) and nickel doped bismuth ferrite (BiFe1-xNixO3) nanoparticles. The synthesis of BiFeO3 and BiFe1-xNixO3 (x = 0.02, 0.04) are done by Sol-Gel method. After synthesis the samples of pure and transition metal ion (Ni) doped bismuth ferrite have been studied by using X-ray diffractometer (XRD), X-ray Photoelectron spectroscopy (XPS), Field Emission Scanning Electron Microscope and Raman Spectroscopy. Optical properties are studied by using UV–vis spectroscopy using different wavelengths (range 300–800 nm). Photocatalytic properties are also studied by degradation of MB dye using prepared samples as photocatalyst. XRD patterns shows that all the prepared samples are crystalline and crystallinity increased by Ni-doping and shifts in XRD peaks by Ni-doping shows the distortion in the structure of BFO. Raman spectroscopy also indicates the rhombohedral distorted structure of Ni-doped BFO in R3C space group. FESEM micrographs shows that Ni-doped BFO has polyhedral and spherical shape grains and Ni doping cause reduction in grain size. Optical band gap reduced due to Ni-doping is shown by the UV–Vis spectroscopy results and Tauc’s plots. The increase in reduction of MB dye due to Ni-doping shows the enhanced photocatalytic properties of BFO by Ni doping.

Polymer blends have been intensively studied because of their theoretical and practical importance in different variety application field. In the present work, the development on hybrid gel polymer based poly(methylmethacrylate) (PMMA) blended with biodegradable polymer namely poly(lactic acid) (PLA) as a host polymer in polymer electrolytes application have been successfully prepared. The effect of PLA in PMMA as hybrid polymer was investigated for their structural properties via fourier transform infrared (FTIR), x-ray diffraction (XRD) and differential scanning calorimetry (DSC). FTIR analysis shown that the interaction between PMMA and PLA has occurred via dipole-dipole forces. XRD analysis revealed the increment of amorphous phase when PLA was added into PMMA. Decreased in Tg value upon addition of PLA into PMMA indicate that the flexibility of the polymer backbone, thus enhanced the amorphous behaviour of hybrid gel polymer. These findings shown that the present hybrid polymer shown favourable properties to be used as host polymer for polymer electrolytes application.

Polybutylene terephthalate (PBT) is a semi-crystalline engineering thermoplastic polyester. PBT offers rapid molding cycles, high heat resistant, crystallinity, fatigue resistance, strength and rigidity, excellent electrical properties, creep resistance, reproducible mold shrinkage and chemical resistance. In this study, PBT was loaded with synthetic graphite and carbon fiber at different weight fractions (10-40 wt.%). PBT-based composites were fabricated by the melt mixing process by using a co-rotating twin screw extruder then thermal, mechanical and morphological properties of filled PBT composites was investigated. Weight fraction of carbon fiber (up to 30 wt.%) increases the tensile strength and flexural strength of PBT, but synthetic graphite loading decreases the tensile strength and flexural strength of PBT. The highest in-plane and through-plane thermal conductivity values were obtained as 9.24 for 40 wt.% synthetic graphite filled composite and 3.41 W/mK for 40 wt.% carbon fiber reinforced composite, respectively. Carbon fiber was found to be more effective in increasing the through-plane thermal conductivities than synthetic graphite., Ege University Research Projects Coordination [18-MUH-027], The author(s) received funding from Ege University Research Projects Coordination (Project no: 18-MUH-027).

Thin films of crystalline and porous metal-organic frameworks (MOFs) have great potential in membranes, sensors, and microelectronic chips. While the morphology and crystallinity of MOF films can be evaluated using widely available techniques, characterizing their pore size, pore volume, and specific surface area is challenging due to the low amount of material and substrate effects. Positron annihilation lifetime spectroscopy (PALS) is introduced as a powerful method to obtain pore size information and depth profiling in MOF films. The complementarity of this approach to established physisorption-based methods such as quartz crystal microbalance (QCM) gravimetry, ellipsometric porosimetry (EP), and Kr physisorption (KrP) is illustrated. This comprehensive discussion on MOF thin film porosimetry is supported by experimental data for thin films of ZIF-8. ispartof: ADVANCED MATERIALS vol:33 issue:17 ispartof: location:Germany status: published

Metal antimony (Sb) is a promising anode material of potassium-ion batteries (PIBs) for its high theoretical capacity but limited by its inferior cycle stability due to the serious volume expansion during cycling. Herein, we design and construct a kind of low-crystalline Sb nanoparticles coated with amorphous Sb2O3 and dispersed into three-dimensional porous carbon via a strategy involving NaCl template-assisted in-situ pyrolysis and subsequent low-temperature heat-treated in air. Significantly, the crystallinity and ratio of Sb/Sb2O3 have been precisely tuned and controlled, and the optimized sample of HTSb@Sb2O3@C-4 displays a high reversible specific capacity of 543.9 mAh g−1 at 0.1 A g−1, superior rate capability and excellent cycle stability (~273 mAh g−1 at 2 A g−1 after 2000 cycles) as an anode of PIBs. The outstanding potassium-ion storage performance can be ascribed to the appropriate crystallinity and the multiple-buffer-matrix structure comprising an interconnected porous conductive carbon to relieve the volume changes and suppress the aggregation of Sb, a Sb nanoparticle core to shorten the ion transport pathways and decrease the mechanical stress, and a low-crystalline Sb2O3 as the shell to consolidate the interface between Sb and carbon as well as facilitate the rapid electron transport. The dynamic analysis shows that the composite is mainly controlled by pseudocapacitance mechanism. This work provides a novel thought to design high-performance composite electrode in energy storage devices.

Nanostructures of layered materials have gained increasing attention in photocatalytic and water-treatment processes. Herein, we report on sub-30 nm SnS2 nanosheets (NSs) which can perform photocatalytic reduction of Cr(VI) to Cr(III) quite efficiently on one hand, while removes large quantities of toxic organic dye molecules by choosing an adsorption mode of operation over photo-degradation on the other hand, unlike most other SnS2 nanostructures. The NSs have a highly extended crystallinity growing perpendicular to the (0 0 1) lattice direction but exhibit poor X-ray diffraction for the 10 l (1 = 1,2,3…) lattice planes. With such defects, the NSs have a narrow bandgap of 2.21 eV and exhibit a significant photocurrent density at near band-edge illumination. Cr(VI) photo-reduction using the SnS2 NSs follows a first-order reaction kinetics (rate constant of 0.10 min-1), five-fold higher than commercial TiO2 (P-25). Furthermore, the NSs adsorb Rhodamine B dye molecules from an aqueous solution by forming a monolayer of dye molecules following a pseudo-second-order kinetic model and exhibit an adsorption capacity of ∼ 53.28 mg/g. We show that the NSs have a Zeta potential of ∼ –22 eV and preferably adsorb cationic dyes only. Thus the SnS2 NSs can be effective for Cr(VI) contaminated waste-water treatment in a photocatalytic manner and can also act as a potential adsorbent for polluting dye molecules either in the presence or absence of sunlight. While both these activities are known for SnS2 as well as other materials, the competitive nature of the two mechanisms while each of them is a possibility has never been investigated. Therefore, besides the high activities, the study highlights the presence of different active sites on the material surface that can respond preferentially to either inorganic or organic impurities.

We report a series of highly stable metallophthalocyanine-based covalent organic frameworks (MPc-dx-COFs) linked by robust 1,4-dioxin bonds constructed through nucleophilic aromatic substitution (SNAr) reaction. The chemical structures and crystallinity of the COFs largely remain unchanged even after treating with boiling water (90 °C), concentrated acids (12 mol/L HCl) or bases (12 mol/L NaOH), oxidizing (30% H2O2) or reducing agents (1 mol/L NaBH4) for three days due to their stable M-Pc building blocks and resilient dioxin linkers. With metallated phthalocyanine active sites regularly arranged in the stable framework structures, MPc-dx-COFs can be directly used as efficient electrocatalysts for the oxygen reduction reaction (ORR) without pyrolysis treatment that has commonly been used in previous studies.

Tailoring the properties of electrospun fibers requires a detailed understanding and control of their microstructure. We investigate the structure/property relationships in fabrics of randomly aligned fibers of polylactide, a prevalent biopolymer, either as-spun or after annealing and solvent-induced crystallization. In-depth characterization by field-emission scanning electron microscope (FESEM), wide-angle X-ray diffraction (WAXD), attenuated total reflection Fourier transform infrared (ATR-FTIR), and modulated temperature differential scanning calorimetry (MT-DSC) reveals that the as-spun fibers comprise crystalline and mesomorphic phases, as well as oriented but mobile amorphous chain segments. These chains are mostly responsible for the low-temperature cold crystallization and for the recovery endotherm around the glass transition, while the mesophase transforms into crystals with nearly zero enthalpy. Such behaviors are attributed to high molecular orientation, which is further evidenced by unveiling a fibrillar superstructure in nanofibers. The thermodynamics and structural evolution under different conditions are described from an energy landscape perspective. Finally, we propose a micromechanism, based on a modified supramolecular model, which helps to elucidate the fibers’ molecular dynamics.

Hybrid organic-inorganic perovskites (HOIPs) have garnered widespread interest, yet stability remains a critical issue that limits their further application. Compared to their three-dimensional (3D) counterparts, two-dimensional (2D)-HOIPs exhibit improved stability. 2D-HOIPs are also appealing because their structural and optical properties can be tuned according to the choice of organic ligand, with monovalent or divalent ligands forming Ruddlesden-Popper (RP) or Dion-Jacobson (DJ)-type 2D perovskites, respectively. Unlike RP-type 2D perovskites, DJ-type 2D perovskites do not contain a van der Waals gap between the 2D layers, leading to improved stability. However, bifunctional organic ligands currently used to develop DJ-type 2D perovskites are limited to commercially available aliphatic and single-ring aromatic ammonium cations. Large conjugated organic ligands are in demand for their semiconducting properties and their potential to improve materials stability further. In this manuscript, we report the design and synthesis of a new set of larger conjugated diamine ligands and their incorporation into DJ-type 2D perovskites. Compared with analogous RP-type 2D perovskites, DJ 2D perovskites reported here show blue-shifted, narrower emissions and significantly improved stability. By changing the structure of rings (benzene vs thiophene) and substituents, we develop structure-property relationships, finding that fluorine substitution enhances crystallinity. Single-crystal structure analysis and density functional theory calculations indicate that these changes are due to strong electrostatic interactions between the organic templates and inorganic layers as well as the rigid backbone and strong π-π interaction between the organic ligands themselves. These results illustrate that targeted engineering of the diamine ligands can enhance the stability of DJ-type 2D perovskites.

In the present investigation, we fabricated strontium (Sr2+) incorporated CsPbI2Br-based inorganic perovskite solar cells in ambient conditions. The morphology, crystallinity, absorption, elemental composition and photoluminescence analysis of the bare CsPbI2Br and CsPb1-xSrxI2Br perovskite thin films were studied systematically to investigate the role of Sr2+ incorporation. It is observed that the surface morphology of the CsPbI2Br perovskite thin film has been improved by partial substitution of Pb2+ by Sr2+ which facilitates photoactive black phase-stabilization and defect passivation. The champion device having CsPb0.98Sr0.02I2Br composition exhibited a power conversion efficiency (PCE) of 16.61% which is much higher than the bare device (13.65%). Furthermore, our CsPb0.98Sr0.02I2Br-based devices maintain > 85% of its initial efficiency over 100 h in ambient conditions.

Crystalline engineering and heterostructure have attracted much attention as effective strategies to improve the electrocatalytic activity for hydrogen evolution reaction (HER). In this study, a new heterostructure catalyst (Ru/RuS2@N-rGO) with low crystallinity was fabricated by a simple and low-temperature method for HER in alkaline solution, applying the Na2SO4 as S source and polypyrrole as N source. Optimizing through the controllable crystalline engineering and composition ratio of Ru and RuS2, the Ru/RuS2@N-rGO heterocatalyst at the calcining 500 °C revealed highly efficient HER activity with overpotential 18 mV at a current density 10 mA/cm2 and remarkable stability for 24 h in 1.0 mol/L KOH. This work provides a facile and effective method in designing advanced electrocatalysts for HER in the alkaline electrolytes by synergistically structural and component modulations.

This work outlines a systematic and detailed study of the modification of anatase TiO2 with tungsten (W). The impact this coupling has on the temperature of the anatase to rutile phase transition and the photocatalytic degradation of 1,4-dioxane, a highly toxic compound that is increasingly present in water bodies is also studied. TiO2 composite photocatalysts with 2, 4, 8 and 16 mol. % W, respectively, were produced using a sol-gel process and then calcined between 500−1000 °C. The crystallinity and phase composition of pure and W-TiO2 photocatalysts were examined using X-ray Diffraction (XRD), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). All W-TiO2 composite photocatalysts demonstrated 100 % anatase crystalline phase at calcination temperatures as high as 800 °C. Due to the retention of 26 % anatase after calcination at 950 °C, 8 mol. % W was established as the optimum W loading for the development of high temperature stable anatase W-TiO2 composite photocatalysts. The % anatase content also significantly impacts the photocatalytic activity of the W-TiO2 composite photocatalysts. In the presence of solar light, 100 % of 1,4-dioxane was successfully degraded by 2-W-TiO2, 4-W-TiO2 and 8-W-TiO2 composite photocatalysts, respectively, calcined at 800 °C. However, as the calcination temperature increases and the % anatase content decreases, only 70 % of 1,4-dioxane was degraded when using 4-W-TiO2 and 8-W-TiO2 calcined at 900 °C. The highest % removal of 1,4-dioxane was also achieved using 8-W-TiO2 calcined at both 800 and 900 °C. 8-W-TiO2 is therefore considered the optimum sample for both photocatalysis and phase transition temperature.

openaire: EC/H2020/788489/EU//BioELCell Funding Information: We thank Dr. Markus Bacher for his support with NMR measurements. This work was performed in part at the Materials Characterization and Fabrication Platform at The University of Melbourne. The authors thank the financial support from the Austrian Biorefinery Centre Tulln (ABCT), the Academy of Finland (Project #311255, “WTF-Click-Nano”), and the H2020-ERC-2017-Advanced Grant “BioELCell” (788489). This research was funded in whole, or in part, by the Austrian Science Fund (FWF) (J4356). Publisher Copyright: © 2021 American Chemical Society. All rights reserved. Selective surface modification of biobased fibers affords effective individualization and functionalization into nanomaterials, as exemplified by the TEMPO-mediated oxidation. However, such a route leads to changes of the native surface chemistry, affecting interparticle interactions and limiting the development of potential supermaterials. Here we introduce a methodology to extract elementary cellulose fibrils by treatment of biomass with N-succinylimidazole, achieving regioselective surface modification of C6-OH, which can be reverted using mild post-treatments. No polymer degradation, cross-linking, nor changes in crystallinity occur under the mild processing conditions, yielding cellulose nanofibrils bearing carboxyl moieties, which can be removed by saponification. The latter offers a significant opportunity in the reconstitution of the chemical and structural interfaces associated with the native states. Consequently, 3D structuring of native elementary cellulose nanofibrils is made possible with the same supramolecular features as the biosynthesized fibers, which is required to unlock the full potential of cellulose as a sustainable building block.

This study presents a method for synthesizing hydroxyapatite (HA) with high crystallinity at low temperatures using a small amount of graphene oxide (GO), and the characters of produced GO/crystalline HA complex was investigated. The morphology and components of the synthesized HA (i.e., HA/GO) were analyzed through scanning electron microscopy, X-ray diffraction and transmission electron microscopy; additionally, the yield of the HA/GO was assessed. The HA/GO results were analyzed by comparing them with those obtained using HA synthesized without GO as a control group. A yield of ~4 mg of HA/GO was attained by the use of 100 μg of GO, demonstrating 20% improvement over the control group. The crystal phase analysis confirmed that crystalline HA of fine quality with nano-size was simply synthesized without intermediate phases using adding a small amount of GO, and the synthesized HA without GO is consist of intermediate phases (brushite and octacalcium phosphate) and hydroxyapatite. Biological characteristics of HA/GO were assessed through the behavioral analysis of mesenchymal stem cell attachment, proliferation, differentiation, and its protein adhesion capacity. HA/GO exhibited excellent biocompatibility and osteogenic differentiation behavior together with better protein adhesion ability than HA. These results demonstrate potential of HA/GO for application in bone tissue engineering. Thus, HA/GO can be developed as a biomimic biocomposite by combining it with bioactive molecules such as growth factors.

In this paper, 3 mol% yttria-doped tetragonal zirconia polycrystal material (3 mol% Y2O3–ZrO2) was prepared using an optimised pressureless sintering process. The phase change and particle size distribution of Y2O3–ZrO2 during sintering were studied, and the effect of sintering temperature on the properties of Y2O3–ZrO2 was analysed. The raw materials and prepared samples were analysed using XRD, Raman spectroscopy, SEM, and Gaussian mathematical fitting. The results show that sintering encourages the transformation of the monoclinic phase into the tetragonal phase, thus improving the crystallinity of the sample. The relative content of the tetragonal phase in the sample increased from 57.43% to 99.80% after sintering at 1200 °C for 1 h. In the range of sintering temperatures studied in this paper (800–1200 °C), the zirconia material sintered at 1000 °C presented the lowest porosity and the best density.

MnO2 nanorods are prepared using a hydrothermal method, and used as precursors for the synthesis of LiMn2O4 nanorod-based active material for the cathode of lithium-ion batteries. The effects of additives, pressure, reactant concentration in the solution, and reaction time during the hydrothermal synthesis on the morphology of MnO2 are examined. For the synthesis of the LiMn2O4 nanorods, two synthetic methods, hydrothermal processing of the MnO2 precursor in a Li-containing solution, and the solid-state reaction of the precursor with LiOH·H2O powder are tested. The morphological and electrochemical properties of the resulting materials are then analyzed. The rate and cycle performances of the LiMn2O4 nanorods are considerably improved by a composite coating of Li-ion-conductive Li2O–2B2O3 and electrically conductive carbon. Because the conductive properties of these coating materials can be obtained with low crystallinity of them, superior coating performance is attainable with relatively low-temperature of after heating, which is advantageous in preserving the morphology of LiMn2O4 nanorods.

Using a convenient high-temperature solid-state method, a novel Zn(W–Mo)O4 red phosphor co-doped with alkaline metal ions and Eu3+ was successfully synthesized. The effects of doping with one charge-compensating agent and mixed multiple charge-compensating agents on the phase composition, crystal structure, crystallinity and luminescence properties of phosphors were studied. Using a theoretical study, the crystal environment around the Eu3+ ion was analysed and the internal quantum yield was calculated. The charge-compensating agent decreases the non-radiative transition by reducing the Zn defect in the phosphor and simultaneously changes the crystal environment around the Eu3+ ions. The enhancement of luminescence intensity of phosphors by co-doping with different charge-compensating agent ions is consistent with single doping. The luminescence intensity was increased 82.64% by doping with a charge-compensating agent, and the colour purity increased to 90.36%, indicating that the Zn(W–Mo)O4:Eu3+ red phosphor can be used as a potential candidate material in white-light-emitting diodes.

Single phase Er3+ activated Na2CaSiO4 (NCSO) phosphors were synthesized successfully via sol-gel technique. As-synthesized NCSO: Er3+ samples have been characterized using various techniques to explore crystallinity, morphology, photoluminescence (PL) features, thermal sensing properties and thermal stability. An intense green emission peak has been observed at 558 nm under 379 nm (near-UV) excitation for NCSO: Er3+ phosphors. Moreover, the Er3+ ions concentration has been optimized at 6.0 mol% in NCSO host lattice to achieve maximum intensity, beyond which the emission intensity reduces due to concentration quenching. Temperature-dependent PL studies indicate excellent thermal stability as the emission intensity persists up to 71% and 66% of the room temperature intensity at 383 K and 423 K, respectively. The chromaticity coordinates (0.328, 0.654) under 379 nm excitation for the optimized NCSO: Er3+ phosphor situated in the green region. Further, the superior temperature sensing behaviour of the proposed phosphor is highly expected from the obtained relative sensitivity value of 1.88% K−1. Above mentioned results indicate the potentiality of the green emitting NCSO: Er3+ phosphor for multifunctional optoelectronic devices.

Here in, a system of Co3O4/CoO catalyst activated with the aid of bisulfite (NaHSO3) was established for the decomposition of methylene blue (MB). The Co3O4/CoO material was designed by a two-step uniform precipitation and calcination method and characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), vibrating sample magnetometer (VSM), X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR) spectroscopy to detect the crystallinity, morphology, magnetic ability, element valence and the different types of free radicals, respectively. The efficient degradation of MB relies on the synergistic effect between the Co3O4/CoO catalyst and bisulfite (NaHSO3) to generate some strongly oxidizing radicals, which could achieve a MB degradation rate of 90.7% within 40 min using this novel system. Additionally, the ferromagnetic property of Co3O4/CoO catalyst is expected to supply an excellent magnetic separation ability to help separate the solid catalyst from the aqueous solution. The novel catalyst system of Co3O4/CoO/NaHSO3 may serve as a promising new system for wastewater treatment.

Titanium dioxide is often used to capture polysulfides due to its strong surface polarity. Surface activity of titanium dioxide is produced by defects, which possesses an important impact on abilities to capture polysulfides. However, the reaction mechanism of defective titanium dioxide in the process of capturing polysulfide is not clear. In this paper, we introduced cobalt source as an additive to titanium dioxide/biomass carbon composite materials to prepare titanium dioxide with many defects and strong surface activities. The crystallinity of biomass carbon surface is also continuously improved by introducing cobalt sources. Under combined performance of highly active titanium dioxide and highly conductive biomass carbon, composite materials possess strong and reversible polysulfide-capturing abilities. In particular, types of polysulfides captured is increased. Herein, the addition of cobalt source is beneficial to enhance abilities of titanium dioxide to capture multiple polysulfides, improve conductivity of composite materials and achieve high reversible capacity (375.0 mA h·g−1 after 500 cycles at 1C).

Cordierite glass-ceramics usually begin to crystallize from the surface. As an efficient nucleating agent, TiO2 can promote the rapid transformation of glass to bulk crystallization, but it is easy to cause the increase of dielectric constant and light absorption. High crystallinity cordierite glass-ceramics were prepared by optimizing the heat treatment process without or with different nucleating agents in stoichiometric cordierite glasses. The results show that the crystallization mechanisms of glasses without and with ZrO2+P2O5 as nucleation agents are controlled by surface crystallization. While, the glass with TiO2+ZrO2+P2O5 as nucleation agents have the tendency to be bulk crystallization. The studied glasses are crystallized from surface and have different crystallization orientations with the inner glass. The thickness of crystalline layer increased with the increasing of heating temperatures, but the “surface-center” crystallization process cannot complete by further increasing heating temperatures because of softening deformation of glasses. At 1020 ℃, the glasses complete the “surface-center” crystallization for long durations. The glasses without nucleation agents and with ZrO2+P2O5 require 10 h, but the glass with TiO2+ZrO2+P2O5 complete for 5 h. Although all the three glasses complete the “surface-center” crystallization, the glasses with nucleation agents show the higher crystallinity upon the same heat treatments. Finally, glass-ceramics with excellent performance were obtained, for example, the Z1# glass-ceramic have the high microhardness ∼7.4 GPa, low thermal expansion coefficient ∼1.4☓10−6 ℃−1 at 20–300 ℃, and relatively high thermal conductivity ∼2.4 W/mK. It also exhibits low dielectric constant and loss, which was ∼4.5 and ∼1.2☓10−3 at 1 MHz, ∼ 4.9 and 2.3☓10−3 at 10.5 GHz..

Cellulose nanocrystals (CNCs) are ideal rheological modifiers for aqueous oil and gas extraction fluids. CNCs are typically produced with sulfuric acid and their aqueous suspensions have uniform and predictable properties under ambient conditions; however, drastic changes occur at elevated temperatures. Herein, the effects of high temperature treatments (ranging from 80 to 180 °C for 1 h to 7 days) on the properties (including uniformity, colloidal stability, and color) of sulfated, phosphated, and carboxylated CNC suspensions were studied. Additionally, cellulose molecular weight, and CNC surface charge content and crystallinity index were quantified before and after heating. CNCs underwent few morphological changes; their molecular weight and crystallinity index were largely unchanged under the conditions tested. Their surface charge content, however, was significantly decreased after heat treatment which resulted in loss of colloidal stability and aggregation of CNCs. The largest change in suspension properties was observed for sulfated CNCs whereas CNCs with a combination of sulfate and phosphate esters, or carboxylate groups, were less affected and maintained colloidal stability at higher temperatures. In fact, desulfation was found to occur rapidly at 80 °C, while many carboxylate groups persisted at temperatures up to 180 °C; calculated rate constants (based on second order kinetics) suggested that desulfation is 20 times faster than decarboxylation but with a similar activation energy. Overall, this study elucidates CNC suspension behavior after heat exposure and demonstrates routes to produce CNCs with improved high temperature performance.

The TaCN coatings were fabricated on Ti-6Al-4V by reactive magnetron sputtering with different nitrogen partial pressures. The results show that the TaCN coatings have a columnar crystal structure of TaC, TaN nano-crystal and amorphous phases (amorphous carbon and CNx). The crystallinity of TaCN coatings decreases with the increase of N2 flow rate. It is found that hardness and adhesive strength have a downward trend and friction coefficient of TaCN coatings increases with the increase of N2 flow rate. In particular, the TaCN coating with lowest N2 flow rate of 30 sccm has the highest hardness (16.3 GPa), the biggest adhesive strength (74.8 N) and the lowest friction coefficient (~0.19). The TaCN coating exhibits an excellent tribological performances even at high temperature. The lowest friction coefficient at 400 °C could reach below 0.1 thanks to the transfer layer containing graphitic clusters which generated during friction.

In recent years, the perovskite solar cells have gained much attention because of their ever-increasing power conversion efficiency (PCE), simple solution fabrication process, flyable, light-weight wearable and deployable for ultra-lightweight space and low-cost materials constituents etc. Over the last few years, the efficiency of perovskite solar cells has surpassed 25% due to high-quality perovskite-film accomplished through low-temperature synthesis techniques along with developing suitable interface and electrode-materials. Besides, the stability of perovskite solar cells has attracted much well-deserved attention. In this article we have focused on recent progress of the perovskite solar cells regarding their crystallinity, morphology and synthesis techniques. Also, demonstrated different layers such as electron transport-layers (ETLs), hole transport-layers (HTLs) and buffer-layers utilized in perovskite solar-cells, considering their band gap, carrier mobility, transmittance etc. Outlook of various tin (Sn), carbon and polymer-based perovskite solar cells and their potential of commercialization feasibility has also been discussed.

With the emergence of non-fullerene acceptors (NFAs), the power conversion efficiencies (PCEs) of all-small-molecule organic solar cells (ASM-OSCs) have been significantly improved. However, due to the strong crystallinities of small molecules, it is much more challenging to obtain the ideal phase separation morphology and efficient charge transport pathways for ASM-OSCs. Here, a high-efficiency ternary ASM-OSC has been successfully constructed based on H11/IDIC-4F system by introduction of IDIC with a similar backbone as IDIC-4F but weak crystallinity. Notably, the addition of IDIC has effectively suppressed large-scale phase aggregation and optimized the morphology of the blend film. More importantly, the molecular orientation has also been significantly adjusted, and a mixed face-on and edge-on orientation has formed, thus establishing a more favorable three-dimensional (3D) charge pathways in the active layer. With these improvements, the enhanced short-circuit current density (JSC) and fill factor (FF) of the ternary system have been achieved. In addition, because of the high lowest unoccupied molecular orbital (LUMO) energy level of IDIC as well as the alloyed structure of the IDIC and IDIC-4F, the promoted open circuit voltage (VOC) of the ternary system has also been realized.

The effects of three types of salt including NaF, KCl, and NaCl on the properties of NiFe2O4 nanoparticles using salt-assisted solution combustion synthesis (SSCS) have been investigated. The synthesized powders were evaluated by SEM, TEM, FTIR, XRD, and VSM analysis. Also, the specific surface area (SSA), as well as size distribution and volume of the porosities of NiFe2O4 powders were determined by the BET apparatus. The visual observations showed that the intensity and time of combustion synthesis of nanoparticles have been severely influenced by the type of salt. The highest crystallinity was observed in the synthesized powder using NaCl. The SSA has also been correlated completely to the type of salt. The quantities of SSA was achieved about 91.62, 64.88, and 47.22 m2g-1 for the powders synthesized by KCl, NaCl, and NaF respectively. Although the magnetic hysteresis loops showed the soft ferromagnetic behavior of the NiFe2O4 nanoparticles in all conditions, KCl salt could produce the particles with the least coercivity and remanent magnetization. Based on the present study, the salt type is a key parameter in the SSCS process for the preparation of spinel ferrites. Thermodynamic evaluation also showed that the melting point and heat capacity are important parameters for the proper selection of the salt.

The effect of mineralizer triethanolamine (TEOA) on crystallization behavior of nano-ZrO2 crystallites preparated by microwave-assisted hydrothermal was investigated using X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and high resolution TEM (HRTEM). The isothermal crystallization kinetics of nano-ZrO2 was studied, and the action mechanism of mineralizer TEOA was discussed. XRD and TEM results indicated that the product is a single tetragonal zirconia (t-ZrO2), and the particle size is 25–30 nm. The addition of mineralizer triethanolamine can significantly improve the nucleation rate and crystallization rate of nano-ZrO2. In order to obtain nano-ZrO2 crystallites with uniform size and good crystallinity, the concentration of TEOA should not be less than 0.3 mol/L (M). There is a good linear relationship between ln[-ln(1-Xc)] and lnt when the concentration of TEOA is 0.3 M, 0.4 M, 0.5 M, indicating that Avrami equation can well describe the crystallization process of nano-ZrO2 crystallites. The crystallization kinetics equations are described by ln[-ln(1-Xc)] = ln0.0005 + 2.25lnt, ln[-ln(1-Xc)] = ln0.025 + 1.28lnt, ln[-ln(1-Xc)] = ln0.4 + 0.57lnt, respectively. With the increase of the concentration of TEOA, the alkali separation of TEOA is carried out continuously, which aggravates the dissolution of colloid and makes the process of crystallization and nucleation easier. Meanwhile, alkoxide ammonium ion formed by alkali ionization can form an electric double layer structure on the surface of zirconia crystallites, thus promoting the dispersion of nano-zirconia powders.

The graphene oxide (GO) reinforced bismuth titanate (BT) nanocomposites were prepared using the hydrothermal method. The prepared nanocomposites were characterized using different analytical techniques to study the structural, morphological, optical, and luminescence properties. The X-ray diffraction pattern of bare and GO reinforced BT nanocomposites reveals the formation of bismuth titanate structure. The morphology of GO substituted samples exhibits the formation of a rod-like structure with decreased particle size compared to bare BT. The EDS spectra of GO incorporated samples show the presence of Bi, Ti, C, and O. The Raman spectra of the prepared samples clearly show the variation in Raman modes of Bi–O and O–Ti–O after substitution of GO. The shift in the XRD and Raman peak position of the GO substituted samples confirm the successful addition of GO and reduction in the crystallinity. BT's reflectance decreased in the visible region after addition of GO, which implies the light absorption is higher in the visible region and enhances the photocatalytic activity of BT. Also, the substitution GO decreased the bandgap energy of BT. The photocatalytic activity of 5% GO substituted nanocomposite completely degrades the direct blue 15. The obtained results conclude that the 5% GO substituted BT nanocomposite beneficial for the degradation of azo dyes, and it will be helpful for industrial wastewater treatment and water remediation.

In the present investigation, titania thin films doped with varying concentrations of Samarium (Sm) were synthesized by spin coating method on glass substrate. The obtained films were annealed at two different temperatures (350 and 450 C) to induce crystallinity. The structural property of these samples was characterized by using X-ray Diffraction (XRD) and Raman spectrometer. The surface morphology of the films was analysed by Field Emission Scanning Electron Microscopy (FESEM) and Atomic Force Microscopy (AFM). The presence of pure anatase phase with enhanced polycrystalline nature was evident for the films annealed at 350 and 450 C. Due to the addition of Sm, the titania thin films exhibited increased crystallinity. The Raman analysis also support the presence of crystalline anatase phase and the existence of defects in the deposited films. The prepared samples were also subjected to photocatalytic activity studies by using methyl orange (MO) dye and the results are discussed herein. The rate constant increased and half life time decreased considerably for 0.4 at% doped samples. The current work provides new ideas for monitoring the structural properties by adding low concentration rare earth dopant into metal oxides (titania) suitable for various applications.

Li–O2 batteries have attracted great attention because of their high theoretical energy density, which exceeds the highest possible value of currently used Li-ion batteries. The operation of Li–O2 batteries include the formation and decomposition of Li2O2 at the cathode, and cell degradation occurs because such discharge products accumulate on the pores and cause pore clogging. For reversible charge–discharge process, in this study, a biaxially multilayered high crystalline carbon nanotube (CNT) web was designed and fabricated by a modified direct spinning method, which was the first demonstration that realize the biaxially multilayered structure in one-step process. The high crystallinity of the CNT surface reduced its decomposition and the biaxial alignment of CNT enabled the web to be opened for O2 gas and electrolytes without pore clogging. The pore size distribution verified that effective pores were better developed in the biaxially multilayered CNT web, which facilitated the flow of O2 gas and electrolytes. The use of this specially designed CNT as a cathode improved the cyclability by 75% and dramatically reduced the overpotential. For the practical use of Li–O2 batteries, a 3D folded cell with biaxially multilayered CNT web electrode is fabricated and demonstrated 30 cycles at 100 W h/kgcell cutoff.

The wettability of materials used in the production of devices employed in various technological domains have attracted significant attentions. Therefore, it is important to design the surfaces of these materials such that they can provide the required surface free energy and simplify the interfacial structure. Herein, various Cu films with a highly controllable surface wettability and a wide range of contact angles ranging from 6° to 152° were fabricated, and the corresponding mechanism was discussed. A wide range of wettability was realized by controlling the surface structure of the Cu film. The nanogap structure of the vertical nanowire-array film led to a high surface free energy. Similarly, the oblique nanowire-array film increased the surface free energy; however, the surface free energy was dependent on the size of the nanowires rather than on the nanogaps owing to the crystallinity of the film. Additionally, cluster-nanowire-array films were designed to realize a wettability transition from hydrophilicity to hydrophobicity with a constant surface free energy. The Cu foam possessed a superhydrophilic surface owing to its high porosity, whereas the cluster-nanoparticle structure possessed a superhydrophobic surface. In addition, we noted that the structure-induced wettability played an important role in tuning the semiconductor and metal interfacial stress and simplifying the interfacial structure. Furthermore, the outstanding electrical conductivity of the Cu films indicates its promising potential as an electrode. The structure-induced wettability proposed in this study can be applied for a wide range of materials, particularly for films used for advanced applications.

Stress relaxation, the decreasing trend of stress at a given strain along with time, is an essential mechanical behavior for any structural material. Graphene fiber (GF), a new kind of carbonaceous fiber, has emerged prominent mechanical performance and multifunctionality since first invented in 2011. However, most of efforts were focused on the improvement of mechanical strength and electrical/thermal conductivity and dynamic mechanical behavior has been ignored. Here, we studied the stress relaxation behavior of GF and revealed a severe stress drop for nascent GF. We found that the drop in stress during relaxation decreased with the promotion of the orientation degree and crystallinity. Plasticization stretching strategy and graphitization process were presented to relieve the relaxation of GF, accompanying with excellent mechanical strength. The optimized GF exhibits best stress relaxation property with 99% stress remained after relaxation. This work reveals an essential relaxation behavior of GFs and develops effective processes to conquer stress relaxation, making GFs for practical applications as structural materials.

The effects of adding ZrO2 and TiO2 at the expense of MgF2 on the crystallization, microstructure, mechanical properties, thermal properties and electrical properties of mica glass-ceramics based on the SiO2–MgO–MgF2–K2O system were investigated by the differential scanning calorimetry (DSC), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), microhardness tester and resistivity tester. The electrical properties were discussed emphatically. The results showed that the additions of ZrO2 and/or TiO2 at the expense of MgF2 effectively increase the viscosity, the glass transition temperatures (Tg) and the crystallization temperatures (Tp) of the glasses. The crystallization activation energy (Ec) of the amorphous glasses varied with the nucleating agents was discussed in depth. It was discovered that the nucleating agents had no effect on the crystal phase type but had a certain effect on the crystallinity and microstructure. Tetrasilicic fluoromica and enstatite were precipitated at different crystallization temperatures. Due to the non-stoichiometric ratio of tetrasilicic fluoromica crystal, the prepared glass-ceramics had high dielectric constant (24.4–34.3) and volume resistivity (>2 × 1011 Ω cm) at 25 °C, and the dielectric loss was almost zero.

The impact of γ-ray on the halide perovskite (CuPbI3) thin film has been investigated in this work. Nanocrystalline and homogeneous CuPbI3 material was effectively deposited on a glass substrate using spin coating method. The thin film, which has a thickness of approximately 227 nm, was exposed to γ-ray's source (Co60 with a dose rate of 7.328 kGy/h) in the range of 0–75 kGy. Then the structural, morphological, electrical and optical properties of CuPbI3 thin films were studied before and after being irradiated. X-ray diffraction (XRD) analysis confirmed the hexagonal phase structure, and the crystalline size decreased from 42 to 16 nm with increasing crystallinity up to 50 kGy. Field emission scanning electron microscopy (FESEM) revealed that the grain size (33-23 nm) and surface of thin films were significantly affected by γ-ray's doses variation. The optical transmission and reflectance of CuPbI3 thin films were studied by means of their response to incident γ-rays. The estimated band gap (Eg) slightly increased from 2.23 to 2.3 eV with increasing γ-rays dose from 0 to 50 kGy and then deceased afterward. Other optical parameters, such as Urbach energy, extinction coefficients, refractive index, optical density and dielectric constants, were determined before and after γ-ray's exposure. Photoluminescence (PL) spectra depict the transition peak at 620.35 nm and the structural defect peak at 606.3 nm. The intensity of the PL peaks could depend on the γ-rays dose with respect to the as-deposited thin films. Impedance spectroscopy of all samples revealed that the grain boundary resistance gradually reduced with increasing γ-ray's dose. This study concludes that the incident γ-rays play a main role in properties of the CuPbI3 thin film, which is favorable for sensing/detecting applications of γ-ray's.

Highly oriented graphitized films demonstrate outstanding thermal conductivity in recent telecommunication applications. In this work, polyimide films were prepared with catalyst pyridine. High orientated and high thermal conductive graphite films were successfully prepared by pure polyimide (PI) films without any other carbon source inducing growth. The result showed that pyridine could promote the imidization of PI. Suitable dosages of pyridine can improve the crystallinity, promote the orderly arrangement of molecular chains, and facilitate the growth of the crystal lattice after graphitization. After graphitization, graphitized PI films exhibited highly oriented layers. The graphitized film coming from a pyridine concentration of 3.5 wt% provided the best thermal conductivity (1092 W / ( m . K ) ), which was 49 times more than those from the thermally imidized films. The average crystalline size of it was 62.16 nm and its degree of graphitization was 90%. Therefore, the graphite film prepared by polyimide formed with catalyst pyridine has the potential of thermal management and is a highly prospective candidate as heat dissipation substrates for miniaturization electronic devices.

The growth of CZTS thin films by electrodeposition has numerous advantages in terms of controlling the deposition parameters. However, the electrochemical cells in conventional potentiostat are small and require precise adjustment. Electrodeposition is feasible by controlling solely the current without using a reference electrode and hence an expensive potentiostat. The cost and surface area limitations can be overcome by utilizing the simple two-electrodes cell and a current source. Therefore, in this study, CZTS thin films were amperometrically deposited on various substrates using our novel two-electrode electrochemical cell setup. The structural, morphological, compositional, optoelectronic properties of the electrodeposited CZTS thin films have been precisely investigated by adjusting the deposition current. Stoichiometry measurements reveal that the chemical composition and hence crystallinity of thin films strongly depend on the applied current. The critical deposition current for Zn-rich films was found to be between 0.97 and 0.98 mA/cm2.