Photoluminescent properties of Sm³⁺ and Tb³⁺ codoped CaWO₄ nanoparticles obtained by a one-step sonochemical method

Luminescent materials with LED applications can have your emission color controlled by rare earth doping. In this work, Sm³⁺- and Tb³⁺-codoped CaWO₄ nanoparticles were obtained by a one-step sonochemical method. The nanoparticles were characterized by X-ray diffractogram (XRD), Raman scattering (RS) spectroscopy, The Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and visible ultraviolet spectroscopy (UV–Vis). The photoluminescent measurements were taken at room and lower temperatures for analysis of doping in emission color. The diffractograms indicate the single-phase CaWO₄ with the scheelite structure and it was observed a reduction in the crystallite size as the doping. SEM and TEM images indicate the formation of nanospheres for pure and samarium-doped samples, while terbium doping results in the formation of nanorods. Room temperature photoluminescence spectra indicate a blue emission for the bare and samarium-doped CaWO₄, while terbium doping emits at the green color. The codoping mixes the colors blue, green, and orange, indicating a potential material with white color emission.