Trigonal Research Articles

Impact of Al3+ substitution in M-type hexaferrite on structural, magnetic, and dielectric properties

Hexaferrites SrAlxFe12−xO19 (x = 0, 1, 2, 3, and 4) doped by Al3+ in an account of Fe3+ were synthesized using microwave digestion. X-ray diffraction pattern analysis revealed that the compound is polycrystalline with a hexagonal M-type structure of SrAlxFe12−xO19 and P63/mmc space group is predominant for all dopants of Al3+ ion. The crystallite size of the SrAlxFe12−xO19 phase has a maximum value for the un-doped sample (94.5 nm) and then decreases for all values of Al-doping. The SEM results showed that the average grain size increased with Al-doping till x = 2 and was almost stable. The magnetic properties were investigated by vibrating sample magnetometer. The results showed a continuous decrease in both saturation (Ms), and remnant (Mr), magnetization with Al-doping. At the same time, the coercive magnetic field, Hc, increases continuously with Al-doping except for x = 4, Hc slightly decreased. These results make these compound candidates to be used in data storage and magnetic memories. Dielectric properties investigation showed low-frequency dispersion in the dielectric results due to a space-charge effect. It has been demonstrated that enhancements in conductivity, dielectric constant (ε′), and dielectric loss (ε′′) rise with an increase in the concentration of Al3+ ions, suggesting that SrAlxFe12−xO19 can be used for microwave absorption and other high-frequency applications.

Optical and magnetic properties of Zn0.9Mn0.05Fe0.05O thin films deposited by RF-magnetron sputtering.

Zn0.9Mn0.05Fe0.05O were synthesized by rf- magnetron sputtering in an argon gas environment show a hexagonal wurtzite structure without any secondary phases of dopants MnO or Fe2O3. The crystallite (D) parameters estimated from the XRD pattern disclose a significant decrease with argon partial gas pressure from 3.34 -11.80 nm. The surface morphology of as-deposited films has a dense columnar microstructure with an average grain size of about 14 -18 nm with roughness (RMS) from ∼2.86 to 7.67 nm. The sputtered thin films exhibit high optical transmittance in the visible range with a significant redshift as a function of working pressure. The energy band gap shows a slight increase with gas pressure in the range of about ∼ 3.05 – 3.36 eV. The films deposited for argon gas pressures of 12 & 15 mTorr have room-temperature ferromagnetism due to oxygen vacancies/ defect concentrations in the host ZnO matrix.

Efficiently enhancing stability for a low concentration HCHO degradation using hexagonal prism MnCe-MOFs catalysts

The efficient and stable removal of indoor formaldehyde (HCHO) a low concentration, as required by the national standard (≤ 0.08 mg/m3), remains a significant challenge. In this study, we investigated a novel hexagonal prism structure of MnCe-MOFs catalysts, synthesized via the hydrothermal method using DMF (N, N-Dimethylformamide), for the complete degradation of HCHO at ambient temperature. Monometallic and bimetallic MOFs materials, as well as the effects of calcination temperature and the stability of these high-performance catalysts in degrading HCHO were investigated and characterized using EDS, XPS, H2-TPR, IR and ESR. Results demonstrated that HCHO degradation using MnCe-MOFs achieved 97.2% efficiency within 48 hours, maintaining above 96% efficiency after three experimental cycles, exhibiting the highest activity and stability. The high performance was attributed to the columnar structure with abundant pores and a high specific surface area, lower initial reduction temperature, and an abundant presence of surface hydroxyl groups. Moreover, the spherical nanoparticles of MnCe-MOFs were uniformly distributed, and the highly dispersed CeOx provided plentiful active sites, contributing to the catalysts’ high activity and stability.

Structural characteristics, P-V-L theory, Raman spectra, and microwave dielectric properties of (La1-xNdx)2(Zr0.96Ti0.04)3(MoO4)9 ceramics for LTCC applications

This article explores the microwave dielectric properties of (La1-xNdx)2(Zr0.96Ti0.04)3(MoO4)9 (x=0.1,0.3,0.5, and 0.7) ceramics prepared by solid-state reaction. Utilizing the Rietveld refinement technique in XRD, the sample is identified as a trigonal crystal system belonging to the R3¯c space group. SEM analysis indicates that relative density has a significant impact on the εr and Q×f of ceramics. The Q×f values of ceramics are closely related to the FWHM of the Raman spectra. At 750℃, (La0.5Nd0.5)2(Zr0.96Ti0.04)3(MoO4)9 ceramic exhibited excellent dielectric properties: εr = 10.4 (±0.08), Q×f = 149,300 (±3,211) GHz, τf = -34.8 (±0.7) ppm/℃. To gain a deeper understanding of the intrinsic mechanisms governing the microwave dielectric properties of ceramics, analysis based on the P-V-L theory reveals that the La(Nd)-O bond and Mo-O bond contribute significantly to εr and Q×f, respectively.

Tunable mechanical properties of the 3D anticircular-curve transversal-isotropic auxetic structure

This work studies a three-dimensional anticircular-curve transversal-isotropic auxetic structure (3D-ATAS) with tunable Poisson’s ratio (υ) and tunable Young’s modulus (E) on the basis of hexagonal symmetry in the transverse plane using the anti-deformation method by the design of inclined rods as circular-curve rods in the opposite direction of the deformation (under compressive loading). By using the energy method, expressions of υ and E of 3D-ATAS are acquired, and based on the periodic boundary conditions, υ and E of 3D-ATAS are parametrically researched through numerical simulation and uniaxial compression experiments. The effects of anticircular-curve rod thickness t, anticircular-curve rod width b, and anticircular-curve cross-section angle θ to υ and E of 3D-ATAS are investigated. The tunable ranges of υ and E of 3D-ATAS are predicted, and the wide range of E is attained. Compared with the 3D circular-curve transversal-isotropic auxetic structure, E of 3D-ATAS is significantly enhanced in different directions, and the maximum enhanced up to 10 times. In the same way, both υ and E of 3D-ATAS are transversal-isotropic.

Time-Dependent Hydrothermal Synthesis of La2O3 NPs for Effective Catalytic Activity of Ionic Dye.

Lanthanum oxide was successfully synthesized by hydrothermal method by varying the reaction time such as 6, 12, and 24 h. In XRD, study confirms the presence of a hexagonal structure, and the phase remains the same at different times; the main goal is to assess the average crystallite size of prepared La2O3 nanoparticles, which was found in the range of 6 to 8 nm. An interesting observation from the XRD data was the apparent increase in crystalline nature as the synthesis time was extended. The UV-Vis spectroscopic studies show a change in the band gap when the reaction time is changed. The morphology analysis shows that the image revealed that the particles formed were agglomerated and formed a spherical shape, with diameters ranging between 35 and 86 nm. When tested for photocatalytic activity, the La2O3 nanoparticles show a degradation of methylene blue dye when the time varies. Remarkably, the nanoparticles synthesized exhibited a profound ability to degrade the dye, with an efficiency rate hitting as high as 89% under halogen light illumination.

Bioefficacy of Zinc oxide nanoparticle synthesis and their Biological, Environmental applications from Eranthemum roseum

Synthesis of metal oxide nanoparticles using medicinal plant increasing rapidly due to its eco-friendly to environment. In this study Zinc oxide nanoparticle is synthesized using the leaf extract of plant E. roseum. Synthesized NPs was characterized using UV- Vis Spectroscopy analysis where the peak observed at 374nm with band gap of 2.5eV, FTIR and XRD analysis validate pure hexagonal structure, Spherical shape of NPs was confirmed by SEM with EDX analysis and main compounds are zinc 75% and oxygen are 22%. Transmission Electron Microscopy Analysis confirms the oval shaped ZnO NPs Biological activity of E. roseum ZnO NPs such as antioxidant assay DPPH, ABTS, hydroxyl radical and reducing power activity shows good inhibition against free radicals. The In-vitro Hypoglycemic effects has maximum inhibition of 96% on α- amylase activity and 87% on α- Glycosidase activity. Anti-inflammatory activity recorded 93% maximum inhibition at Albumin denaturation assay and 75% at Membrane stabilization assay. E. roseum ZnO NPs shows 67.79% on HeGp2 Anti-proliferative cells line. AO/EtBr staining assays confirms the apoptosis effect. Larvicidal activity shows highest mortality of 98.44% on species C. quinquefasciatus. Photocatalytic dyedegradation of Methylene blue dye shows 65% of dye degradation.

3D bi-directional auxetic square metastructure with programmable thermal expansion and Poisson's ratio

Multifunctional integration research on metastructures has become the current development trend and hotspot, especially satellite platforms and hypersonic aircraft in the aerospace field. A 3D bi-directional auxetic square metastructure (BASM) with the programmable coefficient of thermal expansion (CTE) and Poisson's ratio (PR) is designed through the combination of re-entrant hexagonal structures and bi-material triangles. Specimens in the form of the 1*2 array are designed and fabricated through 3D printing. The correctness of the results of finite element analysis (FEA) of the BASM is verified by uniaxial compression experiments. Additionally, FEA is adopted to investigate the effective mechanical properties of the BASM with the form of the 2*3 array, and deformation mechanisms are further explored. Results indicate that the CTE, PR, and stiffness of the BASM depend on material combinations and geometric parameters. Under thermal and mechanical loads, the BASM achieves bi-directional regulation of the CTE and PR, encompassing both axial and circumferential deformations. Notably, the deformation mechanisms and critical conditions of the BASM are explored under the thermo-mechanical load. A novel strategy for programming the PR of the BASM is proposed in addition to changing the geometric parameters and the material combinations.

The Effect of Indium Tin Oxide Nanoparticles (ITO NPs) Incorporated with ZnO NPs based on Structural, Optical and Flexible Dye Sensitized Solar Cells (FDSSCs) Application.

This study aimed to investigate the impact of zinc oxide nanoparticles (ZnO NPs) doped with indium tin oxide nanoparticles (ITO NPs) on polymer-based dye-sensitized solar cells (DSSCs). The ZnO NPs and ITO NPs were synthesized using the sol-gel and co-precipitation methods, respectively. They were then characterized and applied for dye-sensitized solar cells of a polymer-based substrate. Transmission electron microscopic (TEM) analysis revealed the presence of hexagonal structures and small spherical nanoparticles. The mean diameter of the ZnO NPs was found to be 15.22 ± 0.11 nm, while the ZnO NPs doped with ITO NPs (ZnO NPs/ITO NPs) had a mean diameter of 14.54 ± 0.16 nm. The effects of the ITO NPs on the ZnO NPs were evaluated, and it was found that these ITO NPs enhanced the performance of the flexible electrode DSSCs. After the addition of ITO NPs, the power conversion efficiency (PCE) of the ZnO NPs was boosted to be three times higher than that of the ZnO NPs DSSCs without ITO NPs. Similarly, the ultraviolet (UV) band exhibited a red shift, resulting in a lower band gap and reduced charge transfer resistance, which can enhance the PCE of the DSSCs. The polyethylene terephthalate (PET)/indium tin oxide (ITO) (PET/ITO) substrate conductive polymer showed positive outcomes for DSSCs. The PCE value for ZnO NPs was 2.198 ± 0.14%, while for ZnO NPs/ITO NPs, it was 6.680 ± 0.12%. This work achieved remarkable and competitive performance when compared to a solid (indium tin oxides/glass)-based substrate.

Synthesis of aluminosilicate mesoporous material MSU-S from natural resources: Investigating the effects on the structure formation

Zeolite seed-based mesoporous aluminosilicate material MSU-S is normally synthesized from pure chemicals. In the study, MSU-S material was synthesized using natural resources such as rice husk, and kaolin in Vietnam. Here, a systematic investigation is conducted to find the relationship between the synthesis conditions (aging time, hydrothermal time, hydrothermal temperature, pH environment) and the formation of mesoporous structure, as well as the material properties. The sample was characterized by XRD, TEM, N2 adsorption-desorption isotherms, and TGA-DSC. The MSU-S material has been synthesized successfully from rice husk and kaolin. The best conditions are aging time of 24 hours, and hydrothermal conditions at 95 oC during 96 hours with pH=9. The MSU-S has an ordered hexagonal mesoporous structure containing zeolite BEA seed. The pore diameter is concentrated at 2.9 nm. The BET surface area is calculated to be 770 m²/g. Thermal stability is determined to be up to 900 oC.

Structural, Magnetic, and Magneto-Thermal Properties of Rare Earth Intermetallic GdRhIn

We study the structural, magnetic, and magneto-thermal properties of the GdRhIn compound. The room-temperature X-ray diffraction measurements show a hexagonal crystal structure. Temperature and field dependence of magnetization suggest two magnetic transitions—antiferromagnetic to ferromagnetic at 16 K and ferromagnetic to paramagnetic at 34 K. The heat capacity measurements confirm both the magnetic transitions in GdRhIn. The magnetization data were used to calculate isothermal magnetic entropy change and refrigerant capacity in GdRhIn, which was found to be 10.3 J/Kg-K for the field change of 70 kOe and 282 J/Kg for the field change of 50 kOe, respectively. The large magnetocaloric effect in GdRhIn suggests that the material could be used for magnetic refrigeration at low temperatures.

Green synthesis of NiO and NiO@graphene oxide nanomaterials using Elettaria cardamomum leaves: Structural and electrochemical studies

An eco-friendly synthetic route was developed for the formation of nickel oxide (NiOaq and NiOet) nanoparticles (NPs) by treating Ni(NO3)2.6H2O with aqueous/ethanolic extracts of Elettaria cardamomum leaves; the same reaction was performed in the presence of graphene oxide (GO) to produce NiOaq@GO and NiOet@GO nanocomposites (NCs), respectively. The NMs were characterized by XRD, FT-IR, SEM, EDX, UV–visible spectroscopy, and TGA-DSC analysis. They were also subjected to electrochemical investigations and photocatalytic degradation of crystal violet (CV) dye. XRD analysis revealed the average crystallite sizes of 8.84–14.07 nm with a face-centered cubic form of NiO NPs and a hexagonal structure of their nanocomposites with GO. FT-IR spectroscopy confirmed the presence of Ni-O vibrations at 443-436 cm−1. SEM images confirmed the spherical morphology of NiO NPs while NiOaq@GO NCs contained randomly aggregated, thin, and wrinkled graphene sheets. NiOaq and NiOet have shown particle sizes of 27.7–30.63 nm which were decreased to 19.33–26.39 nm in their respective NiOaq@GO and NiOet@GO NCs. EDX spectra verified the homogeneous distribution of elements (Ni, O, C) on the surface of the particles. The synthesized NCs have shown smaller band gaps (NiOaq@GO = 3.74 eV; NiOet@GO = 3.34 eV) as compared to their respective NPs (NiOaq = 5.0 eV; NiOet = 3.89 eV). TGA/DSC data was used to find the thermal stabilities, glass transition temperatures, and enthalpies. Cyclic voltammetry measurements exhibited distinct oxidation and reduction peaks. NCs exhibited better potential as electrode materials for supercapacitor applications as compared to their respective NPs. NiOet@GO exhibited the best electrochemical performance and photocatalytic degradation efficiency of CV dye. After 120 min exposure to sunlight, the degradation coefficient of CV was observed to be 82.93, 86.34, 89.99, 90.27 and 81.65 % in the presence of NiOaq, NiOet, NiOaq@GO, NiOet@GO and GO, respectively.

Influence of Wrinkle Structure on Properties of Na-doped ZnO Films

Un-doped ZnO and Na-doped ZnO (NZO) thin films with various Na doping concentrations were successfully fabricated on glass substrates by a sol-gel process. The effect of Na ions at concentrations of 0, 1, 2, 3, 4, and 5% on the crystalline structure, surface morphology, and optoelectronic properties of ZnO films was studied using appropriate measurement techniques. XRD analysis revealed a polycrystalline hexagonal wurtzite structure in the NZO films. The NZO films' average crystal size ranged from 17.7 nm to 19.6 nm. SEM micrographs showed that wrinkle network appeared in the pure and doped ZnO films due to solvent evaporation during the thermal annealing process. UV-Vis spectroscopy pointed out that the average transmittance of NZO films is as large as ca. 78%. The optical bandgap of the films varied slightly between 3.235 eV for the pure ZnO and 3.246 eV for the Na 5% doped NZO film. When Na ions were doped into the NZO films, the electrical conductivity improved. Moreover, the absorption figure of merit exhibited the largest value of 0.981 Ω-1cm-1 for the fabricated NZO films, which enables the use of these films for solar cells and for other optoelectronic applications.

KEARNS TEXTURE PARAMETERS AND PROPERTIES OF HEXAGONAL MONO- AND POLYCRYSTALS

Problem statement. Polycrystals' physical and mechanical properties are determined by the corresponding properties of single crystals (crystallites) that make up the polycrystal, and their distribution by orientation in the polycrystal (texture). In metals with a hexagonal structure, the use of Kearns texture parameters, which show the degree of coincidence of the hexagonal axis of crystallites with a given direction in a polycrystalline sample, allows determining the property of a polycrystal in this direction, if the properties of a single crystal in the direction of its hexagonal axis and the perpendicular direction are known. It is also possible to solve the inverse problem: determining the properties of a single crystal in the direction of its hexagonal axis and the perpendicular direction based on the properties of the polycrystal and the determined of the Kearns texture parameters. Materials and methods. Elastic and mechanical characteristics of hexagonal alloys based on titanium (Grade 1 and VT1-0) and magnesium (Mg − 10 % Li and ZE10) were studied after different types of deformation − rolling, alternating bending, and twist extrusion. The Kearns texture parameters were determined by the X-ray method based on the data of the construction of inverse pole figures (IPF) in the normal direction (ND) to the sheets plane and the rolling direction (RD). The results of the experiment. It is shown that the specified method allows to calculate the elastic and mechanical properties of the specified polycrystals after they undergo various types of deformation with an error of no more than 5−10 %, as well as to solve the inverse problem of calculating the properties of single crystals with an error of no more than 5 %. Conclusions. Using the parameters of the Cairns texture and the characteristics of single crystals of magnesium alloys ZE10, Mg 5 % Li, titanium Grade1 and VT1-0 made it possible to calculate the corresponding properties of polycrystals and their anisotropy. The use of Cairns texture parameters, experimental values of the modulus of elasticity, tensile strength and yield strength of polycrystalline sheets of the studied magnesium and titanium alloys made it possible to evaluate the characteristics. There are strong correlations between the values of the modulus of elasticity, the mechanical characteristics of the studied sheets of magnesium and titanium alloys, on the one hand, and the corresponding parameters of the Cairns texture, on the other hand.

Water purification and biological efficacy of green synthesized Co/Zn-Doped α-Fe2O3 nanoparticles

In the present study, Co/Zn doped α-Fe2O3 (Hematite) nanoparticles (NPs) were synthesized using polyvinylpyrrolidone (PVP) and Azadirachta indica (AI) leaves aqueous extract. The analytical techniques including XRD, UV, SEM, EDX, VSM, Raman, and FTIR, we were able to identify and characterize the structural, morphological and magnetic attributes of the synthesized NPs. The findings demonstrated that the synthesized NPs exhibit homogeneous spherical shapes with particle sizes ranging from 8.64 to 15.32 nm. The NPs have rhombohedral crystal lattices, with crystallite sizes of 23.25 nm for chemically synthesized doped α-Fe2O3 NPs and 12.52 nm for those synthesized using green methods. The magnetic study has shown that the saturation magnetization (Ms) value of NPs, which ranges from 36 to 45 emu/g at ambient temperature, exhibits superparamagnetic properties (300 K). The treatment of industrial wastewater and its reuse for agricultural purposes are the subjects of the current study. Different concentrations of doped α-Fe2O3 NPs were used as photocatalysts to degrade dyes in a bioreactor under UV light in a heterogeneous mixture. The degradation rates achieved were 96.42 % for Congo Red (CR) and 98.36 % for Eosin Yellow (EY). DPPH assays were conducted to evaluate the antioxidant activity of the synthesized doped α-Fe2O3 NPs. The percentage inhibition of DPPH radicals ranged from 71.13 % to 90.35 %. Our findings indicate that AI leaf extract holds promise as a valuable resource for the development of bioactive compounds and environmentally friendly approaches to synthesizing green NPs. This is primarily attributed to the increased accessibility of bioactive components with potent antioxidant properties. The combination of these benefits provides opportunities for novel uses in environmental cleanup, biological applications, and energy conversion.

The structure, magnetic properties, magnetotransport and temperature coefficient of resistivity of hexagonal 4H-SrMnO3 manganite

The perovskite hexagonal SrMnO3 manganite with four layers (4H-SrMnO3) have been one of the hot topics in materials science due to the physical characteristics of antiferromagnetic, ferroelectric, and thermoelectric effects. The transport properties and magnetoresistance (MR) effect of 4H-SrMnO3 have seldom been reported. The structure, temperature coefficient of resistivity (TCR), magnetic and magnetotransport properties of the 4H-SrMnO3 SrMnO3 manganite obtained by solid state reaction have been investigated in this work. X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) measurements at room temperature reveal that the SrMnO3 sample exhibits a pure hexagonal symmetric structure, with uniform distribution of particles and elements. Under applied magnetic fields of 2000 Oe, the SrMnO3 sample exhibits a transition from antiferromagnetic (AFM) to paramagnetic (PM) behavior at approximately 280 K, known as the Néel temperature (TN). The resistance is influenced by the magnetic field, but overall exhibits an insulating state. Remarkably, the SrMnO3 sample shows significant MR effect near room temperature. The negative MR near room temperature varies from 5.8 % with 1 T field to 16.8 % with 6 T field, indicating an existence of obvious MR in the hexagonal AFM SrMnO3 manganite. Furthermore, the maxmium value of TCR reaches 4.34 % K−1 near room temperature. These findings of room-temperature TCR and room-temperature MR in the AFM 4H-SrMnO3 hold immense value for the research and potential application of the AFM spintronics and devices.

Effect of various processing parameters on the properties of ZnO thin films

Zinc oxide (ZnO) thin films are essential in opto-/piezo-electronics due to their transparency, high electron mobility, wide bandgap (∼3.37 eV), and high excitonic binding energy (60 meV). Effects of processing parameters on ZnO thin films, such as the molarity, ageing, thickness, and calcination temperature, on the microstructural and optical properties deposited by sol-gel spin-coating are investigated under one roof. X-ray diffraction (XRD) confirmed the polycrystalline nature of all films, along with a dominant orientation (002) plane, indicating the formation of a c-axis oriented hexagonal wurtzite structure of ZnO regardless of the processing parameters. Peak intensities varied for all samples and exhibited the highest peak intensity annealed at 500 °C, which correlates with the increase in crystallite size from 15.93 to 16.41 nm due to a decrease in defect density via the thermal expansion. 0.4 M aged solution over 70 h showed the variation in the crystallite size and dislocation density, indicating the improvements in the thin film quality. Thickness-dependent ZnO thin films also improved the crystallinity, which was confirmed by high peak intensities. Decreasing the Urbach energy (Eu) of 0.4 M solution indicates reduced lattice imperfections/defects and high electronic quality of thin-film materials. Deposited ZnO films with an ageing time of 70 h and thickness of 109 nm exhibit the highest refractive index of 3.9 and 2.6, indicating light interaction and optimal density. The optimized conditions of sol-gel derived ZnO thin films augment the ease of development of economic devices for practical implications in opto-/piezo-electronics.

Spray pyrolysis grown Cu and Ni co-doped ZnO thin films: a study of their structural, optical, wettability, and photocatalytic performance

This study explores the impact of Cu and Ni doping on the structural, wettability, optical, and photocatalytic properties of ZnO thin films. The co-doped thin films, with varying Ni concentrations, were deposited using a spray pyrolysis method onto pre-heated soda lime glass substrates. X-ray diffraction analysis confirmed the hexagonal wurtzite structure with preferred orientation primarily along the (002) plane, while crystallinity decreased with higher Ni concentrations. Scanning electron microscopy reveals a compact, adherent structure in all films, with Ni incorporation altering the surface morphology. Fourier transform infrared spectroscopy identified characteristic absorption bands for metal-oxygen bonds. Optical analysis indicated that all thin films exhibited over 88% average transmittance in the visible region, accompanied by a red shift in the optical bandgap. Photoluminescence spectra exhibited a broad emission band in the visible region, indicating intrinsic and extrinsic defects induced by doping. Co-doping transforms the wettability character of ZnO thin films from hydrophilic to hydrophobic. Finally, the photodegradation efficiency of the thin films against methylene blue under sunlight significantly increases from 72% to 92% with an increase in Ni concentration.

Enhanced gas sensing performance of ZnO and Pt-doped ZnO nanostructured films by chemical spray pyrolysis

This study focuses on the preparation and characterization of zinc oxide (ZO) and platinum-doped zinc oxide (Pt-ZO) nanostructured thin films using the chemical spray pyrolysis technique. Structural and morphological properties of the films were investigated via X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). To understand the semiconducting nature and carrier dynamics, UV-Vis spectroscopy, electrical conductivity measurements, and a static gas sensing system were employed. The films exhibited crystallization in the hexagonal wurtzite structure with a preferred orientation along the (002) plane. FESEM images revealed the presence of small bright particles, particularly abundant in the 5 wt% Pt-doped ZO thin film, indicating the presence of platinum catalysts. Electrical conductivity measurements confirmed the semiconducting nature of the films. Optical parameters such as band gap and absorption index were obtained from UV-Vis spectroscopy. Gas sensing performance towards liquefied petroleum gas (LPG) showed that the 5 wt% Pt-doped ZO thin film exhibited a high response (69.9) to a 50 ppm concentration of LPG at 350 °C. The gas response and recovery times were observed to be 8 s and 12 s, respectively. These results are attributed to interactions between LPG molecules and adsorbed oxygen species on the sensor surface. Platinum atoms on the oxide surface facilitate the formation of oxygen vacancies and the dissociation of oxygen molecules at low temperatures, leading to increased adsorption and reaction with LPG molecules. This results in significant changes in the sensor's resistance, thereby amplifying the sensor response. The findings demonstrate the potential of Pt-doped ZO thin films for practical gas sensing applications.

Dual Eu3+ and Er3+ doping in ZnO nanoporous 2D frameworks for tuning photocatalytic activity, linear and non-linear optical response

Recent days, the greater attention of research materials are focusing on the porous nano frame structure due to their distinctive properties and high photocatalytic activity. The porous defective materials revealed a significant role in numerous research fields like sensors, catalysts, energy production, magnetic memory storage, bio medical etc. In our work, pure ZnO and 4f shell shielded rare earth metals doped ZnO metal oxide nanomaterials attributed in the photocatalytic dye degradation, non-linear optical and magnetic properties. We were synthesized pure ZnO and ZnO0.1–2xEuxErxHMT0.1–2x (2x = 0.025,0.05,0.075, 0.010 wt%) nanoparticles using a straightforward hydrothermal route. The hexagonal wurtzite structure of ZnO and Eu:Er-doped ZnO (Eu:Er@ZnO) exhibited by PXRD, and the optical bandgap (Eg) range from 3.14 eV to 3.18 eV was determined by Tauc relation (αhγ)2 = 0. The porous nanoplate morphology of as-synthesized materials revealed by HR-SEM and HR-TEM techniques. All synthesized materials exposed weak ferromagnetic property nature by VSM studies. Among all the synthesized materials, the 0.0025 wt% Eu:Er@ZnO nanoparticles exhibited porous nanoplate structures capable of catalyzing the breakdown of reactive black 5 (RB5) dye, achieving a photocatalytic activity of 93.2 % after 65 min of UV light exposure. The dopant concentration significantly influenced this photocatalytic activity, with lower concentrations showing enhanced performance, particularly in acidic conditions. Moreover, all synthesized porous nano-plate materials followed pseudo-first-order kinetics. Additionally, the Z-scan technique was employed to assess the nonlinear optical properties of the synthesized materials using Q-switched nanosecond Nd laser pulses at 532 nm wavelength. The open-aperture Z-scan revealed reverse saturable absorption (RSA) in all samples. The Eu:Er@ZnO porous nano-plates exhibited promising nonlinear absorption characteristics, with a higher nonlinear absorption coefficient ranging from 5.21 to 7.84 × 10−11 m/W and a lower optical limiting threshold between 0.87 and 0.95 × 1012 W/m2.