Excellent red upconversion luminescence in GdLaO3:Er3+/Yb3+/Sc3+ under 980 nm laser excitation

Abstract

A series of (Gd_0.8−xEr_0.1Yb_0.1Sc_x)LaO₃ and (Gd_0.8Er_0.1Yb_0.1)(La_1−xSc_x)O₃ upconversion luminescence (UCL) phosphors were prepared by solid state sintering technology. The structure, diffuse reflection, and UCL spectra were investigated. (Gd_0.8Er_0.1Yb_0.1)(La_0.9Sc_0.1)O₃ represents excellent red UCL, which is comparable to commercial red β-NaYF₄:Er³⁺/Yb³⁺. Er³⁺/Yb³⁺ are distributed in a continuous double layer structure, blocked by a single layer of Sc³⁺/La³⁺. This structure allows cross relaxation (CR) to occur only in the double-layer structure and improves the efficiency of energy transfer with CR in the double-layer, resulting in the emission of outstanding red UCL. Using the luminescence branching intensity ratio (LIR) technique, the maximum value of relative temperature sensitivity is calculated as 0.01295 K⁻¹ at 303 K. GdLaO₃:Er³⁺/Yb³⁺/Sc³⁺ has excellent pure red UCL and can be applied in luminescence display and temperature sensing.