Dxrxi raman imaging microscope

For structural analysis, powder samples were characterized using Bruker D8 Advance X-ray diffractometer operating at 40 kV tube voltage and 40 mA current in the 2θ range 10 to 90°. The Tecnai G2 TWIN was used to take TEM pictures of the NaYF₄:Yb³⁺/Er³⁺ phosphor while operating at 200 kV acceleration voltages. The Raman spectra of NaYF₄:Yb³⁺/Er³⁺ phosphor were recorded using a Thermo Scientific DXRxi Raman imaging microscope instrument equipped with a 532 nm laser. To capture the photoluminescence (PL) excitation and emission spectra of the powder sample, a fluoromax-plus spectrofluorometer with a 150 W xenon flash lamp was employed (without using an integrating sphere). PL decay measurements were carried out at the same set-up using a pulsed xenon lamp (25 W). The 976 nm tunable continuous-wave diode laser was used as an external excitation source in the same setup to record the UC emissions. A homemade heater equipped with a k-type thermocouple was utilized for the temperature-dependent UC emission measurements, and it was placed right next to the laser's focal point. A variac was used to control the temperature of the (by controlling the voltage of the heater) sample.

Raman spectra are collected in ambient air and at room temperature with a DXRxi Raman imaging microscope (Thermo Scientific). An excitation laser with a wavelength of 532 nm and a mapped area of 100 × 100 µm² are used. An incident power of 10 mW is used to avoid sample damage or laser-induced heating.

All samples were brought into focus using either 20×/0.40NA or 100×/0.9NA microscope objective lenses using a DXRxi Raman imaging microscope (Thermo Fisher Scientific Inc.) with a 780 nm (λ) laser line for SERS analysis. Each spectrum was generated based on 0.1 s collection‐exposures using a 3 mW laser line through a 50 μm slit‐aperture in the range of 600‐1800 cm⁻¹. Chemical imaging was achieved by integrating at least 4000 spectra. The laser spot size was approximately 2.38 and 1.06 μm (ø), respective to the use of 20× and 100× magnification lenses. Single‐cell SERS microscopy was conducted using a 2 μm pixel step‐size and lower magnification images were constructed using a 40 μm pixel step size. Images were analyzed using the OMNICxi Raman SW software (Thermo‐Nicolet, Madison, Wisconsin, USA). Spectra were comparatively analyzed based on discriminatory features that were identified using the TQ Analyst 9.0 software (Thermo‐Nicolet).

The printed pure polymer and BN-filled samples were examined to trace the specific peaks attributed to different components using a Thermo Scientific DXR xi Raman imaging microscope with Thermo Scientific OMNIC xi Raman imaging software. The measurements were conducted at room temperature and at the excitation wavelength of 532 nm from a laser that focused on the samples using a 50× objective for the 100–3500 cm⁻¹ zone. The obtained spectra were exported to the Origin Pro data analysis software for data processing. The baseline was corrected, and the peak heights were normalized to 1.0.

SEM and EDS were conducted on a Zeiss Supra 55VP field emission SEM equipped with a Thermo Fisher Scientific UltraDry EDS detector. The accelerating voltage for SEM and EDS were 3 and 15 kV, respectively. Transmission electron spectroscopy images and elemental mappings were collected using a JEM-2100F microscope equipped with an Oxford energy-dispersive X-ray analysis system, with the accelerating voltage of 200 kV. PXRD was performed on a Bruker D8 Advance powder X-ray diffractometer using Cu Kα radiation. XPS was performed on a Thermo Scientific K-Alpha XPS system with an Al Kα X-ray source. UPS was collected on a Thermo ESCALAB 250Xi XPS system with a He I source gun. The Raman spectra were collected on a Thermo Fisher Scientific DXRxi Raman imaging microscope with a 532 nm laser. The ICP-MS analysis was carried out on a Shimadzu ICPMS-2030 spectrometer. The XAS were collected in the transmission mode at the Advanced Photon Source Beamline 10-BM-B at the Argonne National laboratory. To collect the Co K-edge in the energy window from 7.450 to 8.650 keV, a 71/29 N₂/He gas mixture was used in the I₀ ion chamber to achieve 10% absorption, while a 68/32 N₂/Ar gas mixture was used in the I_t ion chamber to achieve 70% absorption (calculated using Hephaestus at an energy of 7.709 keV). The Co foil standard was used for the energy calibration.

Separated compounds on TLC were located under 254 nm by an Ultraviolet analyzer (YOKO-2F; Wuhan YOKO technology Ltd., Wuhan, China). Raman spectra and its imaging were obtained by use of a DXR™ xi Raman Imaging Microscope (Thermo Fisher Scientific, Waltham, MA, USA) with an excitation wavelength of 532 nm, a resolution of 5.0 cm⁻¹, and a 10× long working distance microscope objective. The excitation power was 10 mW and the integration time was 0.5 s; number of scans was 20. The scan range was 3300~100 cm⁻¹, with a 50 µm confocal pinhole DXR532 full range grating (400 line/mm). Detector was TE-cooled electron-multiplying CCD (EMCCD). Area scanning was chosen as the scanning mode, scanning area was more than 150 μm × 150 μm, and total scanning time was 20 min.
Ultra high-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) was operated on a Dionex UltiMate 3000 ultra-performance liquid chromatography–TSQ quantum mass spectrometer system (Thermo Fisher Scientific, Waltham, MA, USA).

Raman mapping was performed using a DXRxi Raman imaging microscope (Thermo Fisher Scientific Inc., Hudson, USA) equipped with a 532 nm excitation laser. The laser power, exposure time, number of scans, and image pixel size equaled 6.0 mW, 0.00286 s, 11, and 5.0 μm, respectively. System control and spectrum acquisition were conducted using the ThermoScientific OMNIC software.