IR luminescence of CaGa2O4 : Yb3+ when excited by radiation with a wavelength of 940 and 980 nm

Abstract

The article provides an overview of known luminescent materials based on calcium gallate CaGa₂O₄, emitting in the visible and infrared (IR) spectral regions. IR phosphors have not been studied much, but their practical application is of interest. The solid-phase method was used to obtain CaGa₂O₄ samples activated with rare-earth ions Yb³⁺. The structural and luminescent properties of the composition CaGa₂O₄ : Yb³⁺ were studied. When CaGa₂O₄ : Yb³⁺ was excited by radiation with a wavelength of 940 and 980 nm, luminescence was recorded in the range of 980—1100 nm. Based on data on the structure of electronic levels in Yb³⁺ ions, it is concluded that excitation and radiation occur directly in Yb³⁺ ions with the passive participation of the base lattice. Three maximums at a wavelength were recorded on the luminescence spectra: 993 nm, 1025 nm, 1080 nm. The radiation in these bands is due to optical transitions of electrons from the excited to the ground state in Yb³⁺ ions. The dependence of the luminescence intensity in the 993 nm band on the concentration of Yb³⁺ activator ions was studied. It found that the introduction of the phosphor ions Na⁺ increases the intensity of the infrared luminescence. An optimal composition of the phosphor (Ca_1-x-yYb_xNa_y)Ga₂O₄ is proposed, at which the luminescence intensity in the range of 980—1100 nm is maximum.