Optical characterization of spherical fine particles of glassy Eu3+ doped yttrium basic carbonates

摘要

Spherical fine particles of glassy Eu3+ doped yttrium basic carbonate, whose sizes are about 300 nm in diameter, are prepared by a co-precipitation method using urea as a precipitation generator. The optical properties concerned with the f-f transitions of Eu3+ are investigated for the as-prepared powder and the powder samples calcined at 300 and 550degreesC. As the calcination temperature becomes high, the absorption band (charge-transfer band) due to the electron transfer from O2- to Eu3+ shifts to lower energy. The forced electric dipole D-5(0)-F-7(J) (J = 0, 2, 3,4) transition strengths and the inhomogeneous width of the D-5(0)-F-7(J) luminescence spectrum of Eu3+ increase with calcination temperature. From these results, the local structure around Eu3+ is compared among the three powder samples. The persistent spectral hole burning (PSHB) effect is observed at 10, 70, and 120 K in the F-7(0)-D-5(0) transition of Eu3+ in all the samples. It is found that, at these temperatures, the burning reaction rate decreases with increasing calcination temperature. Probable PSHB mechanisms of the three samples are discussed (C) 2002 Elsevier Science B.V. All rights reserved. [References: 41]