CaSnO₃: Yb³⁺, Er³⁺, Ho³⁺ system synthesis and study of its luminescence under IR excitation

Solid state synthesis of Perovskite-like calcium stannate structure activated with three rare-Earth metal ions Yb³⁺,Er³⁺,Но³⁺ has been studied. The formation of the CaSnO₃ : Yb³⁺,Er³⁺,Но³⁺ luminescent structure requires the following synthesis conditions: anneal temperature 1250 °C and duration at least 18 h. The luminescent properties of the specimens have been studied under 960 nm semiconductor diode laser excitation. The luminescence spectra contain bands in the visible and IR spectral regions. Yb³⁺ ions have been shown to act predominantly as sensibilizers capable of transferring part of absorbed energy to Er³⁺ and Но³⁺ ions thus intensifying their respective luminescence peaks. Er³⁺ ions also transfer part of absorbed energy to Но³⁺ ions leading to an increase in the intensity of the 1194 and 1950 nm IR luminescence bands. A schematic of possible energy transitions in the CaSnO₃ : Yb³⁺,Er³⁺,Но³⁺ system under 960 nm laser excitation has been suggested. The energy transfer mechanism between Yb³⁺,Er³⁺ and Но³⁺ions has been described in detail. The luminescence intensity of the luminophore has been studied at 994, 1194, 1550 and 1950 nm as a function of Но³⁺ion concentration. The peak intensity of the 1194 and 1950 nm bands is the highest at a Но³⁺ion concentration of 0.007 at.fr. It has been suggested to use the CaSnO₃ : Yb³⁺,Er³⁺,Но³⁺ luminescent structure for radiation sources capable of converting 960 nm IR radiation to ~2000 nm IR radiation.