Two- and three-photon upconversion of LaOBr:Er3+

In this work, the LaOBr:Er3+ (0.1%) powders were prepared by solid state reaction. The structural properties of LaOBr:Er3+ were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and Raman spectroscopy. The results show that LaOBr:Er3+ has low phonon energy, which indicate that LaOBr:Er3+ may have high luminescent efficiency. Under excitation into I-4(1 1/2) level of Er3+ ions by 980 nm laser, the two- and three-photon upconverted luminescence of LaOBr:Er3+ were recorded. The most intense emissions were come from the H-2(11/2), S-4(3/2) --> I-4(15/2) transitions. The upconversion mechanisms were studied in detail through laser power dependence, and results show that excited state absorption is responsible for the upconversion. The upconversion properties indicate that LaOBr:Er3+ may be used in upconversion phosphors. (c) 2006 Elsevier B.V. All rights reserved.