Controllable crystal form transformation and temperature sensing properties studies of K3Sc0.5Lu0.5F6: Ho3+, Yb3+ with cryolite structure

In this work, a method for controllable regulation of crystal form was proposed for the first time and the effects of different crystal forms on the up-conversion luminescence properties of Ho3+, Yb3+ co-doped K3Sc0.5Lu0.5F6 (KSLF) phosphors was explored. KSLF:Ho3+, Yb3+ phosphors were synthesized by the high temperature solid-state reaction method, and X-ray diffraction (XRD) results illustrate that the compounds can obtain monoclinic phase and cubic phase at different synthesis temperatures. In addition, according to the power-dependent up-conversion luminescence (UCL) intensity, the UCL mechanism and the electronic transition process are discussed. Simultaneously, the temperature sensing behavior of the best samples with different crystal forms at different temperatures was studied by fluorescence intensity ratio technique. All the results show that KSLF:Ho3+, Yb3+ phosphors show great application potential in the field of temperature sensing, and the preparation of KSLF:Ho3+, Yb3+ in different crystal forms can provide a reference value for crystal design and growth.