Spectral analysis of synthesized nanocrystalline aggregates of Er3+:Y2O3

Abstract

The absorption and fluorescence spectra of nanocrystalline aggregates of Y2O3 doped with Er3+ are reported between 8K and room temperature. The nanocrystalline particles were synthesized from a homogenous solution of the metal ions and urea at elevated temperatures in order to control the precipitation of the mixed hydroxides by a slow uniform reaction throughout the solution. The morphology of the calcinated materials revealed uniformly spherical aggregates 200nm or less depending on the ratio of the metal ions in the initial solution. Spectra obtained from these particles were analyzed in detail for the crystal-field splitting of the LJ2S+1 multiplet manifolds of Er3+(4f11) including the ground-state manifold I15∕24, and excited manifolds I9∕24, F9∕24, S3∕24, H11∕22, F7∕24, F5∕24, and F3∕24. Fluorescence lifetimes and results from an analysis of the intensities of manifold-to-manifold transitions are also reported. The sharp-line absorption and emission spectra are comparable to spectra reported earlier for Er3+:Y2O3 grown as large single crystals by a flame fusion method. The results described in the present study suggest that the simple, inexpensive method of preparation that is reported will lead to further investigation of these nanocrystals for their optical properties, especially in the near infrared region of the spectrum.