Nature of local disorder in β-NaYF-based, near-infrared upconverting core nanocrystals due to deliberate incorporation of a symmetry perturbing agent.

As nanocrystalline materials exhibit complex disorders, assessment of the local disorder at the nanoscale induced by implanted lattice defects plays a crucial role in understanding the structure-function relationship in these materials. In this report, a comprehensive structural analysis was performed on upconverting nanocrystals (UCNCs) of NaYF/Nd/Yb/Tm, containing varying concentrations of Li to induce deliberate lattice defects. Subsequently, a comprehensive structural analysis of the UCNCs was performed using synchrotron radiation-based high-resolution X-ray diffraction (HRXRD), high-energy total angle scattering coupled with pair distribution function (PDF) analysis, neutron diffraction (ND) and EXAFS probing.

Behavior of Microstrain in Nd-Sensitized Near-Infrared Upconverting Core-Shell Nanocrystals for Defect-Induced Tailoring of Luminescence Intensity.

In an attempt to optimize the upconversion luminescence (UCL) output of a Nd-sensitized near-infrared (808 nm) upconverting core-shell (CS) nanocrystal through deliberate incorporation of lattice defects, a comprehensive analysis of microstrain both at the CS interface and within the core layer was performed using integral breadth calculation of high-energy synchrotron X-ray (λ = 0.568551 Å) diffraction. An atomic level interpretation of such microstrain was performed using pair distribution function analysis of the high-energy total scattering.

Sub-nanograin metal based high efficiency multilayer reflective optics for high energies.

The present finding illuminates the physics of the formation of interfaces of metal based hetero-structures near layer continuous limit as an approach to develop high-efficiency W/BC multilayer (ML) optics with ML periodicity varying = 1.86-1.23 nm at a fixed number of layer pairs = 400.

In Situ Evolution of Secondary Metallic Phases in Off-Stoichiometric ZrNiSn for Enhanced Thermoelectric Performance.

The full-Heusler (FH) inclusions in the half-Heusler (HH) matrix is a well-studied approach to reduce the lattice thermal conductivity of ZrNiSn HH alloy. However, excess Ni in ZrNiSn may lead to the in situ formation of FH and/or HH alloys with interstitial Ni defects. The excess Ni develops intermediate electronic states in the band gap of ZrNiSn and also generates defects to scatter phonons, thus providing additional control to tailor electronic and phonon transport properties synergistically.

Microwave-Assisted Coprecipitation Synthesis and Local Structural Investigation on NiO, β-Ni(OH)/CoO Nanosheets, and CoO Nanorods Using X-ray Absorption Spectroscopy at Co-Ni K-edge and Synchrotron X-ray Diffraction.

Developing the most straightforward, cheapest, and eco-friendly approaches for synthesizing nanostructures with well-defined morphology having the highest possible surface area to volume ratio is challenging for design and process. In the present work, nanosheets of NiO and β-Ni(OH)/CoO, and nanorods of CoO have been synthesized at a large scale via the microwave-assisted chemical coprecipitation method under low temperature and atmospheric pressure. X-ray absorption spectroscopy (XAS) measurements, which comprises both X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) techniques, have been carried out at Co and Ni K-edges to probe the electronic structure of the samples.