A Promising Orange-Red Nanocrystalline Potassium Lanthanum Orthophosphate for White Light-Emitting Diodes

Abstract

The spectral properties of the K 3 La(PO 4 ) 2 :Eu 3+ nanophosphors synthesized by the combustion method are reported. The phosphors were characterized by X-ray diffraction, transmission electron microscopy, and optical spectroscopy. The XRD pattern reveals a pure monoclinic phase of the K 3 La(PO 4 ) 2 with the average particle size of 30 nm in diameter. Under UV excitation, the phosphors exhibited several emission bands which were assigned to 4f-4f transitions of Eu 3+ ions. The red shade of the Eu 3+ ion with the CIE coordinates (x, y) as (0.63, 0.37) suggests that this material is a promising phosphor for near-UV InGaN-based LED lighting.

Flux Synthesis, Monoclinic Structure, and Luminescence of Europium(III)‐Doped K3La(PO4)2

“…The lack of structural and spectroscopic data for this family of compounds is more likely to have synthetic reasons. The most common route of binary phosphate preparation is the solid‐state technique, although it is followed by the presence of LnPO 4 admixture . On the contrary, molten salt synthesis has shown limited application due to high volatility and thermohydrolysis of molten component alkali metal halides or high melting point in the case of K 4 P 2 O 7 .…”

“…For this reason, the K 3 La(PO 4 ) 2 compound has been chosen for detailed investigation including the search of the synthetic procedure, the peculiarities of doping with europium(III), and the spectroscopic characteristics of the solid solutions prepared. Taking into account that K 3 La(PO 4 ) 2 has been already known and some spectroscopic investigations have been made in the presence of admixtures, no data have been found for luminescence dependence of pure solid solutions yet.…”