Optical temperature sensing behavior and upconversion luminescence in Y₂O₃:Ho/Yb nanocrystal

Y₂O₃:Ho and Y₂O₃:Ho/Yb nanocrystal were prepared by the solution combustion synthesis method. The morphology, structure, and composition of nanocrystals were characterized using transmission electron microscopy (TEM), scanning electron microscope (SEM), and X-ray diffraction (XRD). Luminescent properties of Ho³⁺ were investigated under 488-nm and 980-nm laser excitation. Optical temperature sensing behavior was detected under 488-nm excitation. The effect of Yb concentration in Y₂O_3:Ho/Yb nanocrystal on the upconversion luminescence was investigated. It was found that the fluorescence intensity ratio of red light to green light varied obviously with the concentration of Yb in Y₂O₃ nanocrystal. The color of visible light in upconversion luminescence can be changed by adjusting the Yb concentration.