Spectral Characterization and Excited-State Interactions Between Rare Earth Ions Doped in Borosilicate and Sol-Gel Glasses: Energy Transfer Up-Conversion in the Pr-Sm System

Abstract

ABSTRACTSpectroscopie properties of selected 4f-elements in a sol-gel and two high temperature silicate based glasses are reported. In particular, the spectral properties of the Eu3+ ion have been used to probe the local coordination environment of the f-elements in these glass matrices. Luminescence studies of the high temperature glasses indicated that the electric dipole allowed f-f transitions dominate the spectra which suggests that the local symmetry around the 4f-ions is low. Temperature-dependent spectroscopie studies of the sol-gel glasses indicated that the f-elements retain a “solution-like” environment prior to thermal processing. After heat treatment, an increase in the emission intensities of the electric-dipole transitions is accompanied by a concomitant decrease in the magnetic-dipole allowed transitions. Moreover, excited state interactions has also been observed in the high temperature glasses that contain certain multiple f-elements. In Pr-Sm systems, exclusive excitation of the Sm3+ ion with a 514 nm argon ion laser line provides a higher-energy emission band (ca. 490 nm) from the Pr3+ ion (3P0 → 3H4) transition. This energy up-conversion is attributed to energy transfer from the 6H13/2 level of the Sm3+ ion to the 3Hg6 state of the Pr3+ ion. Following a second photon absorption, the Pr3+ ion is excited to the emitting 3P0level.