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. Ca 2.6 K 0.2 La 0.2 (PO 4) 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 Ca 2·6 K 0·2 La 0·2 (PO 4) 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 Ca 2·6 K 0·2 La 0·13 (PO 4) 2 :0.06Dy3+, 0.01Eu3+ 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 Ca 2·6 K 0·2 La 0·2 (PO 4) 2 : Dy3+, Eu3+ phosphors can be applied to w-LEDs and display devices, and can be used as a new type of optical thermometer. Dy3+/Eu3+ co-doped Ca 2·6 K 0·2 La 0·2 (PO 4) 2 phosphor applied for w-LEDS and temperature sensing. [Display omitted] • Single-phase luminescent materials Dy3+, Eu3+ co-doped Ca 2·6 K 0·2 La 0·2 (PO 4) 2 phosphor with whitlockite structure was synthesized for the first time. • The concentration quenching and energy transfer mechanisms were investigated. • The emission color of Ca 2·6 K 0·2 La 0·2 (PO 4) 2 : Dy3+, Eu3+phosphors changes from natural white light to warm white light with the increase of Eu3+ concentration. • The samples showed temperature sensing performance with maximum S a to be 2.06 × 10−3 K−1 and S r to be 0.181% K−1 under 303 K. [ABSTRACT FROM AUTHOR]