figshare
Browse

Average and Local Crystal Structure of β‑Er:Yb:NaYF4 Upconverting Nanocrystals Probed by X‑ray Total Scattering

Posted on 2017-07-21 - 18:33
The average and local structures of ∼22 nm β-Er:Yb:NaYF4 upconverting nanocrystals were probed using a dual-space approach combining Rietveld and pair distribution function analysis of X-ray total scattering. Comparison of the fits provided by the structural models derived from P6̅2m, P6̅, and P63/m space groups demonstrates that the latter yields a crystallochemically meaningful description of the nanocrystals’ average and local structures. This result is in line with those previously reported for bulk β-Na3xRE2–xF6 (x ∼ 0.45; RE = Y, Er, Tm, Yb) using powder X-ray diffraction, and for β-NaREF4 (RE = Y, Lu) nanocrystals using solid-state NMR; however, it differs from those reported in studies of β-NaREF4 (RE = La, Gd, Er) single crystals, which favored the structural model derived from the P6̅ space group. The proposed structural model features sodium cations distributed in four translation-equivalent chains, each shifted relative to the others along the c axis. Interestingly, the structural model derived for the mineral gagarinite (NaCaREF6, P63/m), in which sodium cations are distributed in eight chains, also provides an adequate fit to the X-ray scattering data. The potential implications of this finding are discussed from the perspective of the size dependence of the crystal structure of β-NaREF4.

CITE THIS COLLECTION

DataCite
3 Biotech
3D Printing in Medicine
3D Research
3D-Printed Materials and Systems
4OR
AAPG Bulletin
AAPS Open
AAPS PharmSciTech
Abhandlungen aus dem Mathematischen Seminar der Universität Hamburg
ABI Technik (German)
Academic Medicine
Academic Pediatrics
Academic Psychiatry
Academic Questions
Academy of Management Discoveries
Academy of Management Journal
Academy of Management Learning and Education
Academy of Management Perspectives
Academy of Management Proceedings
Academy of Management Review
or
Select your citation style and then place your mouse over the citation text to select it.

SHARE

email
need help?