Luminescence characteristics of Y2SiO5 : Tb phosphor particles directly prepared by the spray pyrolysis method

Abstract

Tb-doped Y2SiO5 phosphor particles were prepared directly by a continuous droplet-to-particle preparation process using an ultrasonic spray generator. The photoluminescence characteristics of as-prepared and calcined particles were investigated. The particles of Y2SiO5 prepared below 1100 degrees C had poor crystallinity because of the short residence time of the particles inside the hot wall reactor, while the particles of Y2SiO5 prepared at 1200 degrees C had sharp crystallinity. The crystal structure of Y2SiO5 particles was changed from the X1 to X2 type after calcining above 1400 degrees C. Both prepared and calcined particles had spherical morphology, submicron size, and narrow size distribution. Agglomeration of particles did not occur even after calcining at 1200 degrees C. The prepared Y2SiO5:Tb particles absorbed excitation energy in the range from 220 to 325 nm, and the maximum excitation wavelength was near 240 nn. The main emission peak was 538 nn. The optimum brightness was obtained at the doping concentration of 4 atom %. The activation of terbium occurred directly even at short reaction times inside the hot wall reactor. The brightness of as-prepared particles increased with increasing temperature because of good activation and crystallization in high temperatures. The PL intensity of as-prepared particles at 1200 degrees C was 96% in comparison with maximum intensity of calcined particles. (C) 1999 The Electrochemical Society. S0013-4651(98)04-012-9. All rights reserved.