Quantax edx detector

Pieces of sintered pellets were mounted
in epoxy pucks and polished using sandpaper and a polishing wheel
(1 μm colloidal diamond suspension) for SEM/EDS analysis with
a Thermo Fisher Quattro ESEM equipped with a Bruker Quantax EDX detector.
An Everhart–Thornley detector was used to collect secondary
electron images with 20 kV accelerating voltage, and an annular backscatter
detector was used for Z-contrast to analyze composition. EDS data
from 10 spots, analyzed with the Bruker ESpirit software package,
are provided in Supporting Information, Table S3. Na content was below the detection level of the instrument
(<0.3 atomic %), so elemental maps for Na were not acquired.

NMR-spectra were acquired on a Bruker Avance III 400 spectrometer using CDCl₃ or DMSO-d₆ as a solvent. The ESI-MS data were recorded using a Bruker micrOTOF II spectrometer. UV/VIS spectroscopic analysis was performed using an Agilent Cary 60 spectrometer. SEM measurements were performed using a Zeiss FESEM Auriga 40™ Crossbeam and a Hitachi TM3000 Tabletop SEM with a Bruker Quantax EDX Detector for the EDX measurements. EDX line scans were performed at a Zeiss Gemini 500 equipped with an Oxford EDX Ultim Max 100 detector. FT-IR spectra were recorded by using a PerkinElmer Spectrum 100 spectrometer using ATR unit. TGA measurements were measured on a Netzsch STA449 F3 Jupiter. All measurements were performed under oxygen atmosphere with 80 mL min⁻¹ flowrate and a heating rate of 10 K min⁻¹. Fluorescence microscopy was performed at labelled excitation wavelengths using a Zeiss Axio Observer Z1 microscope.

The sintered pellets were cut with a Buehler
Isomet diamond saw, and slices were mounted in epoxy pucks to be polished
using sandpaper and a polishing wheel (1 μm colloidal diamond
suspension) for SEM and EDS analysis. A Thermo Fisher Quattro ESEM
instrument equipped with a Bruker Quantax EDX detector, an Everhart–Thornley
detector, and an annular backscattered detector with 15 kV accelerating
voltage was used to collect elemental maps and electron micrographs.
The SEM micrographs and EDS elemental maps of Yb and Sb for the x = 0.25, 0.50, and 1.0 samples are provided in SI, Figure S3 and quantitative data in Table S4.