Search

The synthesis of binary (ZnO) 0.4 (CdO) 0.6 nanoparticles was achieved using a novel thermal treatment method. The structural, morphological, elemental composition and optical behaviour of these nanoparticles were determined using various techniques. X-ray diffraction of the sample at a calcination temperature above 500 °C showed the presence of both hexagonal and face-centred cubic crystalline structures. With increasing calcination temperature, the dispersion of the nanoparticles was improved, and the mean particle size determined by TEM micrographs suggested a corresponding increasing trend. Increased particle size led to a rise in the photoluminescent intensity as demonstrated by photoluminescence spectra, and multiple energy band gaps which lessen with increasing calcination temperature. The resulting (ZnO) 0.4 (CdO) 0.6 nanoparticles are likely to have widespread uses within numerous semiconductor applications. [ABSTRACT FROM AUTHOR]

In this research, a thermal treatment method was used to synthesize cadmium oxide nanoparticles. The metal precursor, cadmium nitrate and a capping agent were dissolved in deionized water, which later was dried and crushed into powder. The powder underwent calcination treatment of 500, 550, 600, and 650 °C to crystallize the nanoparticles and to remove organic compounds. The structural studies of CdO nanoparticles have been carried out using EDAX, FTIR, XRD, SEM and TEM. The FTIR and XRD spectra showed that the crystalline structure formation of metal oxide nanoparticles has only occurred after been exposed to calcination. The optical properties which were determined using a UV–vis spectrophotometer showed a decrease in the band gap with increasing calcination temperature. These results prove that the thermal treatment method is a simple technique that can produce pure metal oxide nanoparticles with no other chemicals added. [ABSTRACT FROM AUTHOR]

Facility agriculture has been widely used around the world due to its effective strategy of increasing the added value of agricultural products. The study of Mn4+ doped oxidized red phosphors has become a prominent area of research aimed at addressing the shortage of red light in agriculture and horticulture. In this work, SrZnAl 10 O 17 far-red phosphors doped with Mn4+ were deliberately designed through a high-temperature solid-state reaction. The crystal structure was determined through Rietveld refinement, and a comprehensive analysis of the photoluminescence properties was conducted. When illuminated with light at either 396 or 552 nm, the SrZnAl 10 O 17 :Mn4+ phosphors displayed a distinct narrow emission band, covering the wavelength range of 600–800 nm, with a peak occurring at 692 nm. Notably, the photoluminescence intensity of these phosphors did not show significant variations under 396 and 552 nm light excitation—a relatively uncommon occurrence in Mn4+-doped red oxide phosphors. Furthermore, the photoluminescence spectra of SrZnAl 10 O 17 :Mn4+ phosphors closely matched the absorption spectra of PFR, suggesting the potential application of these phosphors in agricultural cultivation. [ABSTRACT FROM AUTHOR]

In this study, binary nickel oxide silver oxide nanoparticles (NiO) x (Ag 2 O) 1 − x (NPs) were synthesised for the first time using the thermal treatment route at higher and lower precursor values. Two precursors and 5 g of polyvinyl pyrrolidone (PVP) were employed to obtain the (NiO) x (Ag 2 O) 1 − x NPs at 700 °C. The obtained NiO NPs documented cubic and hexagonal phases when assessed with X-ray diffraction (XRD) at (x = 0.4 and 0.6) and (x = 0.2 and 0.8), respectively. The cubic phase was confirmed for Ag 2 O NPs in all prepared samples. The smallest crystallite and particle sizes were found at x = 0.8. The particle size ranged from 23.0 to 45.0 nm, which was evaluated with a transmission electron microscope (TEM). Two shapes, NiO doped with porous Ag 2 O nanosheets, were observed with a scanning electron microscope (SEM). The purity of the products was evaluated via energy-dispersive X-ray (EDX) spectroscopy. The synthesised NPs were composed of nickel (Ni), silver (Ag), and oxygen (O). Moreover, the X-ray photoelectron spectroscopy (XPS) analysis performed during this study revealed the chemical states of the Ni, Ag, and O present, which confirmed the purity of the NPs. The ultraviolet–visible spectroscopy (UV–Vis) assessment conducted also demonstrated that the energy band gaps for nickel oxide (NiO) and silver oxide (Ag 2 O) increased with rising x values. The photoluminescence (PL) analysis performed in this study also verified the existence of two emission peaks attributable to NiO and Ag 2 O, indicating that the NPs possess good photocatalytic activity. Consequently, the NPs synthesised in the present study could be applied as antimicrobial agents in wastewater treatment. [ABSTRACT FROM AUTHOR]

YFeO 3 (YFO) thin films were deposited onto quartz substrates via sol-gel spin-coating technique and annealed at different temperature ranged between 650 and 900 °C. The impact of annealing temperature on the phase formation, microstructural, optical, photoluminescence (PL) and magnetic properties of the films were systematically investigated. X-ray diffraction analysis revealed an amorphous structure in film annealed at 650 °C and formation of hexagonal-YFO (h -YFO) phase in films annealed at 750–800 °C. The films annealed at 850–900 °C exhibited an orthorhombic-YFO (o -YFO) structure. Atomic force microscopy images of h -YFO films showed homogeneous surface with uniform particles size and shape. The particle size increased and had irregular shape in o -YFO films. The average particle size was 44 and 117 nm, while the root square roughness was 1.38 and 2.55 nm for h - and o -YFO films annealed at 750 and 850 °C, respectively. The optical band gap (E g) was 2.53 and 2.86 eV for h - and o -YFO films annealed at 750 and 850 °C, respectively. The PL spectra of h -YFO films were red-shifted compared with that of o -YFO films. The PL emission related to near band edge was observed at 459.0 and 441.9 nm for h - and o -YFO films annealed at 750 and 850 °C, respectively. The magnetization was enhanced with the increasing of annealing temperature and has the value of 4.8 and 12.5 emu/cm3 at 5000 Oe for h - and o -YFO films annealed at 750 and 850 °C, respectively. [ABSTRACT FROM AUTHOR]

Close-packed cubic copper ferrites (CuFe 2 O 4 ) nanoparticles were synthesized using an effective thermal-treatment method directly from an aqueous solution containing copper and iron nitrates as metal precursors and poly(vinyl pyrrolidone) as a capping agent. The FTIR spectra of the calcined samples revealed the vibration bands of Fe–O and Cu–O at 315 and 535 nm respectively. The structural, morphological, optical and magnetic properties of the nanocrystal powder samples were analyzed using various characterization techniques. The powder X-ray diffraction unveiled the formation of spinel phase of CuFe 2 O 4 with the average particle size determined from TEM images increased from 24 to 34 nm at the calcination temperatures between 773 and 1173 K. The band gap calculated using Kubelka–Munk function from the UV–visible diffuse reflectance spectra decreased from 2.64 to 2.45 eV with increasing calcination temperature. The electron spin resonance (ESR) spectroscopy confirmed the presence of unpaired electrons in the calcined samples. The g -factor increased from 2.10497 to 2.57056 and the resonance magnetic field decreased from 3.11599×10 −7 to 2.55161×10 −7 A/m with increasing calcination temperature. [ABSTRACT FROM AUTHOR]

In this work, a systematic coupling study of silane coupling agent between starch and epoxidized soybean oils (ESO) was carried out. Starch was modified by 3-aminopropyl trimethoxy silane (APMS) with various contents of NaOH. The APMS-modified starch was incorporated with ESO to synthesize the bioplastics by solution casting. As demonstrated by the FTIR spectra, the hydrogen bond interactions among starch molecules were inhibited by the modification. This outcome provided higher interaction and compatibility of starch with ESO, as confirmed by FESEM. TGA showed that the thermal stability of starch decreased considerably after the silylation. In contrast, the produced bioplastics with silylated starch exhibited higher thermal stability than the control sample. Regarding the bioplastics, an obvious increase of tensile strength from 5.78 MPa to 9.29 MPa was obtained. This work suggested a simple and effective modification technique by APMS to improve compatibility of starch/ESO-based bioplastics with superior mechanical and thermal properties. [Display omitted] [ABSTRACT FROM AUTHOR]

The structural, optical, electrical and magnetic properties of In 1.95 Cr 0.05 Cu 0.025 O 3 thin film annealed in hydrogen at different temperature (T H = 300, 400, 500, and 600 °C) were investigated. The film was amorphous at T H = 300 °C and had single phase In 2 O 3 at T H = 400 °C, while mixed phases of In 2 O 3 , In and CuCr 2 O 4 were observed at T H = 500 and 600 °C. At T H = 400 °C the film showed semiconducting like behavior. The film's transparency decreased with increasing T H , and optical band gap decreased from 3.67 eV for film annealed at T H = 400 °C to 3.0 eV for film annealed at T H = 600 °C. The magnetization increased for film annealed at T H = 400 and 500 °C while it disappeared at T H = 600 °C. The structural and physical properties were discussed and compared with that for film annealed in air at T Air = 500 °C. • The impacts of hydrogen annealing on the structural and physical properties of In 1.925 Cu 0.025 Cr 0.05 O 3 are reported. • The hydrogen annealing temperature affected the film crystallization and phase formation. • At T H = 400 °C the film is single phase and exhibited semiconducting behavior. • The optical band gap decreased from 3.67 eV for film annealed at T H = 400 °C to 3.0 eV for film annealed at T H = 600 °C. • The magnetization increased for film annealed at T H = 400 and 500 °C while it disappeared at T H = 600 °C. [ABSTRACT FROM AUTHOR]