Color tunable warm white emitting whitlockite-type phosphor applied in optical thermometry

Whitlockite-type structure phosphors have received extensive attention and research due to their adjustable chemical compositions in isomorphic compounds and providing rich crystal positions for doping activators. Ca2.6K0.2La0.2(PO4)(2) whitlockite-type phosphors with Dy3+ singly doping and Dy3+, Eu3+ co-doping were prepared via high temperature solid-phase reaction, and the crystallographic characteristics, luminescence properties and temperature sensing performance were investigated in detail. The prepared phosphors are pure phase and both Dy3+ and Eu3+ enter into the matrix and produce blue, yellow and red emissions. The CCT values of the emitted light from Ca2.6K0.2La0.2(PO4)(2): Dy3+, Eu3+ phosphors increase with the Eu3+ concentration rises, changing from cold white light to warm white light. The integrated emission intensity of Dy3+ in the phosphor decreases with the change in the doping ratio of Dy3+ and Eu3+, causing by the energy transfer from Dy3+ to Eu3+. The Ca2.6K0.2La0.13(PO4)(2):0.06Dy(3+), 0.01Eu(3+) phosphor shows temperature sensing performance based on FIR technique, with the maximum relative sensitivity calculated to be 0.181% K-1 . All the results reveal that the Ca2.6K0.2La0.2(PO4)(2) : Dy3+, Eu3+ phosphors can be applied to w-LEDs and display devices, and can be used as a new type of optical thermometer.