Evo 18 research unit

The crystalline phase, crystallinity and crystal strain in the samples have been analyzed using X-ray diffraction (XRD) technique. The XRD patterns of the samples have been recorded using Cu, K_α radiation (λ = 0.15406 nm) from a MiniFlex 600 (Rigaku, Japan) unit at 2° min⁻¹ scan speed. The Rietveld analysis of the XRD patterns of the samples was performed using FullProf Suite.^{31 (link)} The scanning electron microscope (SEM) has been used to record the morphological features of the samples with a Zeiss, Evo 18 Research unit. The elemental analysis of the samples was carried out using the energy dispersive spectroscopic (EDS) measurements. The Fourier transform infrared (FTIR) measurements of the phosphor samples were carried out using a Perkin Elmer IR spectrometer (FT-IR/FIR Frontier spectrometer) to verify different molecules present in the samples. The upconversion spectra of the phosphor samples have been monitored using 976 nm excitation from a diode laser and an iHR320, Horiba Jobin Yvon, monochromator attached with PMT (photomultiplier tube) at various input pump powers and temperatures.

The crystalline nature and phase purity of the phosphor samples were analyzed by monitoring the XRD patterns using Rigaku diffractometer (MiniFlex 600-unit and Cu Kα radiation with λ = 0.15406 nm). The scanning electron microscope (SEM) (Zeiss, Evo 18 Research unit) was used to study the morphological structure of the phosphor samples. The elements present in the phosphors were verified by the energy dispersive X-ray spectroscopic (EDS) studies. The Fourier transform infrared (FTIR) spectra were monitored to know the vibrational groups present in the phosphors using a PerkinElmer IR spectrometer (I-Frontier unit). The downshifting photoluminescence spectra of all the samples were recorded using Fluorolog-3 spectrophotometer (Horiba Jobin Yvon) attached with a 450 W Xenon lamp as a source of light (Horiba Jobin Yvon). We have also measured the lifetime of ⁵D₀ level of Eu³⁺ ion using the same unit attached with a 25 W pulsed Xenon lamp.