LAUSR

Abstract The series of Tm-doped phosphates Ca9-xZnxLa0.9(PO4)7:0.1Tm3+ for using in phosphor-convertible white LEDs (pc-WLED) with β-Ca3(PO4)2-type structure were synthesized using a standard high temperature route. Intense emission in the blue region of the visible spectrum was observed due to 4f-4f transitions of the Tm3+ ion. The phosphates have been characterized by X-ray powder diffraction (XRD), second harmonic generation (SHG), and luminescence spectroscopy. These phosphors show a satisfactory blue performance due to the 1D2 – 3F4 (≈ 450 nm) transition of Tm3+ excited by n-UV light (358 nm). The crystal structure transforms R3c → R 3 ¯ c upon Ca2+ → Zn2+ substitution, and leads to increase of the integral intensity in 4 times compared with unsubstituted phosphate. Increasing of color purity peaking in x = 1 was also observed. The obtained characteristics is higher than that for the commercial blue phosphor BaMgAl10O17:Eu2+. Generally, Ca9-xZnxLa(PO4)7:Tm3+ phosphates are a new kind of potential blue emitting phosphors for white light-emitting diodes.