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11 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on NaYF4 by Materials Project

NaYF4 is Fluorite-derived structured and crystallizes in the tetragonal I4_1/amd space group. The structure is three-dimensional. Na1+ is bonded in a body-centered cubic geometry to eight equivalent F1- atoms. All Na–F bond lengths are 2.43 Å. Y3+ is bonded in a body-centered cubic geometry to eight equivalent F1- atoms. All Y–F bond lengths are 2.31 Å. F1- is bonded to two equivalent Na1+ and two equivalent Y3+ atoms to form a mixture of edge and corner-sharing FNa2Y2 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NaYF4 by Materials Project

NaYF4 crystallizes in the trigonal P3 space group. The structure is three-dimensional. there are three inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 3-coordinate geometry to nine F1- atoms. There are a spread of Na–F bond distances ranging from 2.25–2.91 Å. In the second Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six F1- atoms. There are three shorter (2.27 Å) and three longer (2.54 Å) Na–F bond lengths. In the third Na1+ site, Na1+ is bonded in a 9-coordinate geometry to nine F1- atoms. There are six shorter (2.47 Å) and three longer (2.55 Å) Na–F bond lengths. There are three inequivalent Y3+ sites. In the first Y3+ site, Y3+ is bonded in a 9-coordinate geometry to nine F1- atoms. There are a spread of Y–F bond distances ranging from 2.30–2.39 Å. In the second Y3+ site, Y3+ is bonded in a 9-coordinate geometry to nine F1- atoms. There are a spread of Y–F bond distances ranging from 2.30–2.39 Å. In the third Y3+ site, Y3+ is bonded in a 9-coordinate geometry to nine F1- atoms. There are six shorter (2.32 Å) and three longer (2.40 Å) Y–F bond lengths. There are four inequivalent F1- sites. In the first F1- site, F1- is bonded in a 3-coordinate geometry to one Na1+ and three Y3+ atoms. In the second F1- site, F1- is bonded in a 5-coordinate geometry to three Na1+ and two Y3+ atoms. In the third F1- site, F1- is bonded to two Na1+ and two Y3+ atoms to form a mixture of distorted edge and corner-sharing FNa2Y2 tetrahedra. In the fourth F1- site, F1- is bonded to two Na1+ and two Y3+ atoms to form a mixture of distorted edge and corner-sharing FNa2Y2 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NaYF4 by Materials Project

NaYF4 crystallizes in the hexagonal P-6 space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six F1- atoms. There are three shorter (2.26 Å) and three longer (2.57 Å) Na–F bond lengths. In the second Na1+ site, Na1+ is bonded in a 9-coordinate geometry to nine F1- atoms. There are six shorter (2.47 Å) and three longer (2.54 Å) Na–F bond lengths. There are two inequivalent Y3+ sites. In the first Y3+ site, Y3+ is bonded in a 9-coordinate geometry to nine F1- atoms. There are a spread of Y–F bond distances ranging from 2.30–2.40 Å. In the second Y3+ site, Y3+ is bonded in a 9-coordinate geometry to nine F1- atoms. There are six shorter (2.32 Å) and three longer (2.39 Å) Y–F bond lengths. There are three inequivalent F1- sites. In the first F1- site, F1- is bonded in a distorted trigonal non-coplanar geometry to three Y3+ atoms. In the second F1- site, F1- is bonded to three Na1+ and two equivalent Y3+ atoms to form distorted FNa3Y2 square pyramids that share corners with two equivalent FNa3Y2 square pyramids, corners with six equivalent FNa2Y2 tetrahedra, edges with four equivalent FNa3Y2 square pyramids, and edges with six equivalent FNa2Y2 tetrahedra. In the third F1- site, F1- is bonded to two Na1+ and two Y3+ atoms to form distorted FNa2Y2 tetrahedra that share corners with three equivalent FNa3Y2 square pyramids, corners with ten equivalent FNa2Y2 tetrahedra, edges with three equivalent FNa3Y2 square pyramids, and edges with two equivalent FNa2Y2 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NaYF4 by Materials Project

NaYF4 crystallizes in the monoclinic Pc space group. The structure is three-dimensional. there are three inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six F1- atoms. There are a spread of Na–F bond distances ranging from 2.26–2.42 Å. In the second Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six F1- atoms. There are a spread of Na–F bond distances ranging from 2.26–2.51 Å. In the third Na1+ site, Na1+ is bonded in a 9-coordinate geometry to nine F1- atoms. There are a spread of Na–F bond distances ranging from 2.35–2.60 Å. There are three inequivalent Y3+ sites. In the first Y3+ site, Y3+ is bonded in a 9-coordinate geometry to nine F1- atoms. There are a spread of Y–F bond distances ranging from 2.32–2.41 Å. In the second Y3+ site, Y3+ is bonded in a 9-coordinate geometry to nine F1- atoms. There are a spread of Y–F bond distances ranging from 2.33–2.40 Å. In the third Y3+ site, Y3+ is bonded in a 9-coordinate geometry to nine F1- atoms. There are a spread of Y–F bond distances ranging from 2.32–2.41 Å. There are twelve inequivalent F1- sites. In the first F1- site, F1- is bonded to two Na1+ and two Y3+ atoms to form distorted FNa2Y2 tetrahedra that share corners with fifteen FNaY3 tetrahedra, corners with two equivalent FNa2Y2 trigonal pyramids, and edges with six FNa2Y2 tetrahedra. In the second F1- site, F1- is bonded to one Na1+ and three Y3+ atoms to form distorted FNaY3 tetrahedra that share corners with sixteen FNa2Y2 tetrahedra, a cornercorner with one FNa2Y2 trigonal pyramid, edges with five FNaY3 tetrahedra, and an edgeedge with one FNa2Y2 trigonal pyramid. In the third F1- site, F1- is bonded to one Na1+ and three Y3+ atoms to form distorted FNaY3 tetrahedra that share corners with fifteen FNa2Y2 tetrahedra, corners with two equivalent FNa2Y2 trigonal pyramids, and edges with six FNaY3 tetrahedra. In the fourth F1- site, F1- is bonded to two Na1+ and two Y3+ atoms to form a mixture of distorted corner and edge-sharing FNa2Y2 tetrahedra. In the fifth F1- site, F1- is bonded to two Na1+ and two Y3+ atoms to form distorted FNa2Y2 tetrahedra that share corners with fifteen FNaY3 tetrahedra, corners with two equivalent FNa2Y2 trigonal pyramids, edges with five FNa2Y2 tetrahedra, and an edgeedge with one FNa2Y2 trigonal pyramid. In the sixth F1- site, F1- is bonded to two Na1+ and two Y3+ atoms to form a mixture of distorted corner and edge-sharing FNa2Y2 tetrahedra. In the seventh F1- site, F1- is bonded to one Na1+ and three Y3+ atoms to form a mixture of distorted corner and edge-sharing FNaY3 tetrahedra. In the eighth F1- site, F1- is bonded to two Na1+ and two Y3+ atoms to form distorted FNa2Y2 tetrahedra that share corners with sixteen FNa2Y2 tetrahedra, a cornercorner with one FNa2Y2 trigonal pyramid, edges with five FNaY3 tetrahedra, and an edgeedge with one FNa2Y2 trigonal pyramid. In the ninth F1- site, F1- is bonded to two Na1+ and two Y3+ atoms to form distorted FNa2Y2 tetrahedra that share corners with fifteen FNa2Y2 tetrahedra, corners with two equivalent FNa2Y2 trigonal pyramids, edges with five FNaY3 tetrahedra, and an edgeedge with one FNa2Y2 trigonal pyramid. In the tenth F1- site, F1- is bonded to two Na1+ and two Y3+ atoms to form a mixture of distorted corner and edge-sharing FNa2Y2 tetrahedra. In the eleventh F1- site, F1- is bonded to two Na1+ and two Y3+ atoms to form distorted FNa2Y2 trigonal pyramids that share corners with seventeen FNa2Y2 tetrahedra and edges with six FNaY3 tetrahedra. In the twelfth F1- site, F1- is bonded to two Na1+ and two Y3+ atoms to form a mixture of distorted corner and edge-sharing FNa2Y2 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NaYF4 by Materials Project

NaYF4 is Fluorite-derived structured and crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. Na1+ is bonded in a body-centered cubic geometry to eight equivalent F1- atoms. All Na–F bond lengths are 2.44 Å. Y3+ is bonded in a body-centered cubic geometry to eight equivalent F1- atoms. All Y–F bond lengths are 2.31 Å. F1- is bonded to two equivalent Na1+ and two equivalent Y3+ atoms to form a mixture of edge and corner-sharing FNa2Y2 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NaYF4 by Materials Project

NaYF4 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are three inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six F1- atoms. There are a spread of Na–F bond distances ranging from 2.28–2.47 Å. In the second Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six F1- atoms. There are a spread of Na–F bond distances ranging from 2.28–2.38 Å. In the third Na1+ site, Na1+ is bonded in a 9-coordinate geometry to nine F1- atoms. There are a spread of Na–F bond distances ranging from 2.38–2.58 Å. There are three inequivalent Y3+ sites. In the first Y3+ site, Y3+ is bonded in a 9-coordinate geometry to nine F1- atoms. There are a spread of Y–F bond distances ranging from 2.31–2.42 Å. In the second Y3+ site, Y3+ is bonded in a 9-coordinate geometry to nine F1- atoms. There are a spread of Y–F bond distances ranging from 2.31–2.40 Å. In the third Y3+ site, Y3+ is bonded in a 9-coordinate geometry to nine F1- atoms. There are a spread of Y–F bond distances ranging from 2.32–2.41 Å. There are twelve inequivalent F1- sites. In the first F1- site, F1- is bonded to two Na1+ and two Y3+ atoms to form a mixture of distorted edge and corner-sharing FNa2Y2 tetrahedra. In the second F1- site, F1- is bonded to two Na1+ and two Y3+ atoms to form a mixture of distorted edge and corner-sharing FNa2Y2 tetrahedra. In the third F1- site, F1- is bonded to two Na1+ and two Y3+ atoms to form a mixture of distorted edge and corner-sharing FNa2Y2 tetrahedra. In the fourth F1- site, F1- is bonded to two Na1+ and two Y3+ atoms to form a mixture of distorted edge and corner-sharing FNa2Y2 tetrahedra. In the fifth F1- site, F1- is bonded to two Na1+ and two Y3+ atoms to form a mixture of distorted edge and corner-sharing FNa2Y2 tetrahedra. In the sixth F1- site, F1- is bonded to two Na1+ and two Y3+ atoms to form a mixture of distorted edge and corner-sharing FNa2Y2 tetrahedra. In the seventh F1- site, F1- is bonded to one Na1+ and three Y3+ atoms to form a mixture of distorted edge and corner-sharing FNaY3 tetrahedra. In the eighth F1- site, F1- is bonded to two Na1+ and two Y3+ atoms to form a mixture of distorted edge and corner-sharing FNa2Y2 tetrahedra. In the ninth F1- site, F1- is bonded to two Na1+ and two Y3+ atoms to form a mixture of distorted edge and corner-sharing FNa2Y2 tetrahedra. In the tenth F1- site, F1- is bonded to one Na1+ and three Y3+ atoms to form a mixture of distorted edge and corner-sharing FNaY3 tetrahedra. In the eleventh F1- site, F1- is bonded to two Na1+ and two Y3+ atoms to form a mixture of distorted edge and corner-sharing FNa2Y2 tetrahedra. In the twelfth F1- site, F1- is bonded to one Na1+ and three Y3+ atoms to form a mixture of distorted edge and corner-sharing FNaY3 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Chemically Driven Multistep Crystallization in the Synthesis of Sodium Yttrium Fluoride Via a Porous, Electrochemically Active Intermediate

Two-step crystallization mechanisms based on liquid–liquid phase separations followed by crystallization are commonly observed both in the laboratory and in nature. While this pathway quite often occurs as a result of a chemical reaction, the subsequent nucleation and growth are often considered as separate, discrete events from the reaction itself. We show this mechanism in the aqueous synthesis sodium yttrium fluoride, but by using a combination of experimental techniques and computational modeling, we show an additional step of solid-state chemical diffusion that is essential to the nucleation mechanism. In this system, we observe at least four distinct steps in the crystallization process, including (1) the segregation of aqueous ions into a dense liquid phase, (2) the formation of a metastable amorphous aggregate, (3) the continuous, gradual solid-state diffusion of sodium and fluoride ions into the amorphous aggregate toward a NaYF4 stoichiometry, and (4) the crystallization of a stable cubic sodium yttrium fluoride phase. Unlike previous descriptions of nucleation and growth, we find that the stoichiometry of the final solid phase evolves throughout the crystallization process rather than being determined at the time of the initial separation from solution. Further, this emphasizes that the chemical reaction cannot be assumed to be a separate event from the phase separation and growth, especially in compounds with variable stoichiometry. We also find that the amorphous aggregate that forms prior to the ion incorporation step adopts a porous, gel-like structure, which we isolated and showed to be electrochemically active, allowing for its potential use as a battery anode in lithium and sodium ion batteries, among other potential applications.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Short-Wave Infrared Upconverting Nanoparticles

Optical technologies enable real-time, noninvasive analysis of complex systems but are limited to discrete regions of the optical spectrum. While wavelengths in the short-wave infrared (SWIR) window (typically, 1700-3000 nm) should enable deep subsurface penetration and reduced photodamage, there are few luminescent probes that can be excited in this region. Here, we report the discovery of lanthanide-based upconverting nanoparticles (UCNPs) that efficiently convert 1740 or 1950 nm excitation to wavelengths compatible with conventional silicon detectors. Screening of Ln3+ ion combinations by differential rate equation modeling identifies Ho3+/Tm3+ or Tm3+ dopants with strong visible or NIR-I emission following SWIR excitation. Experimental upconverted photoluminescence excitation (U-PLE) spectra find that 10% Tm3+-doped NaYF4 core/shell UCNPs have the strongest 800 nm emission from SWIR wavelengths, while UCNPs with an added 2% or 10% Ho3+ show the strongest red emission when excited at 1740 or 1950 nm. Mechanistic modeling shows that addition of a low percentage of Ho3+ to Tm3+-doped UCNPs shifts their emission from 800 to 652 nm by acting as a hub of efficient SWIR energy acceptance and redistribution up to visible emission manifolds. Parallel experimental and computational analysis shows rate equation models are able to predict compositions for specific wavelengths of both excitation and emission. These SWIR-responsive probes open a new IR bioimaging window, and are responsive at wavelengths important for vision technologies.

Qi, Xiao↗
DOE OSTI2025

Enhanced upconversion and photoconductive nanocomposites of lanthanide-doped nanoparticles functionalized with low-vibrational-energy inorganic ligands

Upconverting nanoparticles (UCNPs) convert near-infrared (IR) light into higher-energy visible light, allowing them to be used in applications such as biological imaging, nano-thermometry, and photodetection. It is well known that the upconversion luminescent efficiency of UCNPs can be enhanced by using a host material with low phonon energies, but the use of low-vibrational-energy inorganic ligands and non-epitaxial shells has been relatively underexplored. Here, we investigate the functionalization of lanthanide-doped NaYF4 UCNPs with low-vibrational-energy Sn2S64- ligands. Raman spectroscopy and elemental mapping are employed to confirm the binding of Sn2S64- ligands to UCNPs. This binding enhances upconversion efficiencies up to a factor of 16, consistent with an increase in the luminescent lifetimes of the lanthanide ions. Annealing Sn2S64--capped UCNPs results in the formation of a nanocomposite comprised of UCNPs embedded within an interconnected matrix of SnS2, enabling each UCNP to be electrically accessible through the semiconducting SnS2 matrix. This facilitates the integration of UCNPs into electronic devices, which we demonstrate through the fabrication of a UCNP-SnS2 photodetector that detects UV and near-IR light. Our findings show the promise of using inorganic capping agents to enhance the properties of UCNPs while facilitating their integration into optoelectronic devices.

Pan, Jia-Ahn↗
DOE OSTI2022

Solid-state laser refrigeration of core-shell polystyrene microspheres

Microlaser designs based on the coupling of whispering gallery modes (WGMs) with the upconversion processes which take place within lanthanide-doped nanoparticles (UCNPs) have been demonstrated and shown to have many valuable qualities, such as high Q factors and low lasing thresholds. One obstacle that these microlaser designs still face is the challenges caused by photothermal heating of the gain medium, which could be solved through the design of a radiation balanced microlaser. In this work, WGM microresonators composed of 5 µm diameter polystyrene spheres are fabricated with a layer of Yb3+-doped NaYF4 UCNPs in order to test if the anti-Stokes cooling properties of the UCNPs can cool the microresonator and its environment under laser irradiation. We find via calibrated mean fluorescence spectroscopy that the UCNPs can cool their local environment by as much as 23 °C and significantly reduce the heating of the aqueous environment surrounding the microresonator, showing promise for inclusion in a design for a radiation balanced microlaser.

whispering gallery modes, optical refrigeration, m↗