Preparation of LaPO4:Ce,Tb phosphor with different morphologies and their fluorescence properties

LaPO4:Ce.Tb phosphor was prepared by firing the LaPO4:Ce,Tb precipitate derived from co-precipitation of aqueous solution of LaCeTb mixed rare earth nitrate with ammonium dibasic phosphate. Effects of ripening condition of precipitate, flux addition and firing temperature on the morphology and photoluminescence properties of LaPO4:Ce.Tb phosphor were investigated. It was found that ripening of LaPO4,Ce,Tb precipitate with mother liquor at pH=1 and 130 C for 24 h produced strip phosphor with width of 100 nm and length of 1 mu m. While ripening at either 85 or 130 degrees C after pH adjustment with ammonia generated spherical particles of about 100 nm in size. Types of flux employed significantly influenced the morphology of the phosphor. When H3BO3 was used as flux spherical particles of ca. 300 nm were formed. In contrast, when Li2CO3 or Li3PO4 was employed as flux either separately or a component of double flux, uniform spherical or near spherical particles of ca. 5 mu m were generated. Firing temperature of 1100 and 1200 degrees C in the presence of double flux led to the formation of smooth spherical particles with diameter of ca. 5 mu m, and the phosphor prepared with double flux showed higher brightness than the commercial phosphor. (c) 2008 Elsevier B.V. All rights reserved.