Preparation and Sensing Performance Study in Ultra-wide Temperature Range of K3LuF6:Er3+,Yb3+ Up-converting luminescent materials with Cryolite Structure

Cryolite-type materials have advantages of low phonon energy, easy rare-earth ion doping, and stable physicochemical properties, and they are considered as ideal matrices for up-converting luminescent materials. In this paper, a series of K3LuF6:Er3+,Yb3+ up-converting materials with cryolite structure were prepared for the first time by high-temperature solid-phase method. The compositions, structures and luminescent properties were systematically characterized by X-ray powder diffractometry (XRD), field emission scanning electron microscopy (SEM) and fluorescence spectroscopy (PL). Under 980 nm excitation, the sample emission spectra mainly consisted of green and red emission bands with peaks at 525, 546 and 662 nm, corresponding to the 2H11/2-4I15/2, 4S3/2-4I15/2 and 4F9/2-4I15/2 electron transitions of Er3+, respectively. In addition, the temperature sensing characteristics of two thermally coupled energy levels (2H2/11 and 4S3/2) were studied based on fluorescence intensity ratio (FIR) technique in the range of 79-579 K. All the results show that K3LuF6:Er3+/Yb3+ up-converting luminescent materials have excellent temperature sensing performance in the ultra-wide temperature range and have broad application prospects in the field of temperature sensing.