Energy transfer, superior thermal stability and multi-color emitting properties of langbeinite-type solid-solution phosphor K2Dy1.5–xEuxTa0.5(PO4)3

Langbeinite type compounds are a large kind of oxometallate with good flexibility structure. Herein, we synthesized a new langbeinite type compound K 2 Dy 1.5 Ta 0.5 (PO 4 ) 3 , in which the Dy 3+ and Ta 5+ were blended to occupy the same crystallographic sites. Simultaneously, solid solutions of K 2 Dy 1.5– x Eu x Ta 0.5 (PO 4 ) 3 ( x  = 0–1.5) were prepared and their photoluminescence properties were investigated. Due to energy transfer from Dy 3+ to Eu 3+ , both Dy 3+ and Eu 3+ characteristic emissions are observed under 393 nm light excitation . The emitting color of K 2 Dy 1.5– x Eu x Ta 0.5 (PO 4 ) 3 turns from green through yellow to red by simply adjusting the Eu 3+ concentration from 0 to 0.4. Moreover, K 2 Dy 1.48 Eu 0.02 Ta 0.5 (PO 4 ) 3 phosphor possesses excellent fluorescence thermal stability and exhibits zero thermal quenching at 150 °C. These results manifest that K 2 Dy 1.5– x Eu x Ta 0.5 (PO 4 ) 3 solutions are promising multi-color emitting phosphors candidate for near-UV LED.