Structure, particle size, and annealing of gas phase-condensed Eu 3+ :Y 2 O 3 nanophosphors

Nanofertilizers: The Next Generation of Agrochemicals for Long-Term Impact on Sustainability in Farming Systems

The microflora of the soil is adversely affected by chemical fertilizers. Excessive use of chemical fertilizers has increased crop yield dramatically at the cost of soil vigor. The pH of the soil is temporarily changed by chemical fertilizers, which kill the beneficial soil microflora and can cause absorption stress on crop plants. This leads to higher dosages during the application, causing groundwater leaching and environmental toxicity. Nanofertilizers (NFs) reduce the quantity of fertilizer needed in agriculture, enhance nutrient uptake efficiency, and decrease fertilizer loss due to runoff and leaching. Moreover, NFs can be used for soil or foliar applications and have shown promising results in a variety of plant species. The main constituents of nanomaterials are micro- and macronutrient precursors and their properties at the nanoscale. Innovative approaches to their application as a growth promoter for crops, their modes of application, and the mechanism of absorption in plant tissues are reviewed in this article. In addition, the review analyzes potential shortcomings and future considerations for the commercial agricultural application of NFs.

Green fabrication of lanthanide-doped hydroxide-based phosphors: Y(OH)3:Eu3+ nanoparticles for white light generation

Phosphors can serve as color conversion layers to generate white light with varying optical features, including color rendering index (CRI), high correlated color temperature (CCT), and luminous efficacy. However, they are typically produced under harsh synthesis conditions such as high temperature, high pressure, and/or by employing a large amount of solvent. In this work, a facile, water-based, rapid method has been proposed to fabricate lanthanide-doped hydroxide-based phosphors. In this sense, sub-micrometer-sized Y(OH)₃:Eu³⁺ particles (as red phosphor) were synthesized in water at ambient conditions in ≤60 min reaction time. The doping ratio was controlled from 2.5-20 mol %. Additionally, first principle calculations were performed on Y(OH)₃:Eu³⁺ to understand the preferable doping scenario and its optoelectronic properties. As an application, these fabricated red phosphors were integrated into a PDMS/YAG:Ce³⁺ composite and used to generate white light. The resulting white light showed a remarkable improvement (≈24%) in terms of luminous efficiency, a slight reduction of CCT (from 3900 to 3600 K), and an unchanged CRI (≈60) as the amount of Y(OH)₃:Eu³⁺ was increased.

Fabrication of a core–shell–shell particle with a quarter-wave thick shell and its optical properties

In the present work, core–shell–shell particles with quarter-wave thick shells have been synthesized using chemical solution processes for the first time and the optical properties are discussed both theoretically and experimentally.

Ionic Liquid Assisted Sol-Gel Prepared Ce-Doped ZnO

Ce4+-doped zinc oxide was prepared by Ionic liquid assisted sol - gel method using oxalic acid and zinc acetate as starting material for the first time. And rhodamine B as the target material to study ionic liquid assisted preparation of Ce4+-doped ZnO photocatalytic performance. ZnO was determined by SEM and XRD for introduction of ionic liquids and Ce4+ derived from nano-ZnO surface morphology and crystal before and after. The results show that the Ce4+-doped nano-ZnO crystal structure of a rod. In ionic liquids based on the Ce4+-doped photocatalytic properties of ZnO better. The degradation of rhodamine B 30min when the degradation rate of 90%.

Effect of methanol on the Lewis acidity of rutile TiO2 nanoparticles probed through vibrational spectroscopy of coadsorbed CO

Infrared spectroscopy of adsorbed CO has been used to characterize the effect of adsorbed methanol on the Lewis acidity of 4 nm rutile TiO(2) nanoparticles. Measurements of CO absorbance and vibrational frequency have revealed that CO adsorbs primarily at one class of Lewis acid sites on clean TiO(2) particles, where evidence for lateral interactions between neighboring molecules suggests dense coverage occurs near saturation. The response of the CO infrared intensities and frequencies to methanol exposure has shown that methanol uptake occurs primarily at the Lewis acid sites and through hydrogen bonding to surface OH groups. These surface sites appear to be responsible for driving both molecular and dissociative adsorption of methanol on the titania. Most importantly, these studies have revealed that the parent methanol and associated methoxy products lower the Lewis acidity of neighboring sites on TiO(2) nanoparticles.

Aerosol synthesis and characterization of nanostructured particles of Y3Al5O12:Ce3+ and Y2O3:Eu3+

Nanostructured YAG:Ce3+ and Y2O3:Eu3+ were synthesized by low temperature (320?C) aerosol synthesis-LTAS and high temperature (900?C) aerosol synthesis-HTAS, respectively. The synthesis included aerosol generation from a nitrate precursor solution by an ultrasonic atomizer (1.3 MHz). The obtained aerosol was introduced into a tubular flow reactor, using air as the carrier gas, where successively, on a droplet level, evaporation/drying, precipitation and thermolysis occurred. The obtained powders were collected and thermally treated at different temperatures (900-1200?C). The phase development and the morphology were investigated by the X-ray powder diffraction method (XRPD) and scanning electron microscopy combined with energy dispersive spectrometry (SEM/EDS). Structural refinement was performed using the Rietveld method with the Fullprof and Koalariet programs. The average crystallite size for the Y2O3:Eu system was calculated using the Profit program. It was shown that 89 wt.% of Y3Ai5Oi2:Ce was obtained by annealing (1000?C/6 h) the as prepared, amorphous powder, synthesized by the low temperature aerosol method (LTAS). High temperature spray pyrolysis (HTAS) at 900?C led to the formation of the targeted cubic phase of Y2O3:Eu3+. The microstructural parameters of the asprepared samples of the Y2O3:Eu3+ system indicate the formation of nanostructures with crystallite size smallest than 20 nm. The substitution of luminescent centers (Ce3+, Eu3+) into a host lattice (YAG, Y2O3, respectively) was confirmed by changes in the crystal lattice parameters. Also, it was shown in both systems that good morphological characteristics (non-a?gglomerated, spherical, submicron particles) were obtained enabling improved luminescent characteristics.

Photoluminescence and spectral holeburning in europium-doped MgS nanoparticles

Luminescence and power-gated spectral holeburning studies have been performed on Eu-doped MgS nanoparticles. These particles are atomically tailored to produce and control the relative concentration of Eu(2+) and Eu(3+), which is necessary for power-gated holeburning. The spectral holes are permanent at low temperatures. Optical studies show that the electron-phonon coupling is stronger in nanoparticles than in thin films or microparticles of the same material. This is the reason for inherently broader spectral holes in nanoparticles as compared to microparticle or thin-film samples. Temperature broadening of spectral holes in nanoparticles follows a T(2.4) behavior, a faster rate than thin films or microparticles. This behavior can be attributed to the glassy nature of the particles produced.