Optical characterization, absorption and upconversion luminescence in Er3+and Er3+/Yb3+doped In2O3 phosphor

Combustion derived In2O3:Er3+, co-doped with Yb3+phosphor powders have been prepared. Powder X-ray diffraction, scanning electron microscopy, energy dispersive X-ray and Fourier transform infrared spectroscopy methods are used to characterize the prepared phosphor powders. The intensity parameters (Ωλ, λ=2, 4 and 6), radiative transition probabilities (AR), radiative lifetime (τR) and branching ratios (β) of certain emission transition of Er3+ions for In2O3:Er3+and In2O3:Er3+/Yb3+phosphors have been estimated in the framework of the model given by Judd-Ofelt. Upon excitation at 978 nm, upconversion luminescence properties of Er3+and Er3+/Yb3+doped In2O3 phosphors are investigated. The results obtained from optical study confirm the existence of an effective Yb3+to Er3+energy transfer process and it also predict possible mechanisms to populate the 4S3/2 and 4F9/2 levels. The possible upconversion mechanisms are discussed for Er3+and Yb3+ions with energy level diagram.