High-efficiency near-white emission of Bi3+/Sm3+ co-doped double-perovskite phosphors for optical thermometry

Abstract

Near-white emission phosphors of the Bi3+/Sm3+ co-doped double-perovskite Ca2YTaO6 were successfully prepared via a simple solid-state reaction. The crystal structures and lattice parameters as functions of doping ion type and its content were analyzed. Note that all the prepared samples have the monoclinic structure with the space group of P 21/n (14). Their lattice parameters were enlarged with the increment of doping ion content since the Y3+ ion with the smaller radius was substituted by the Bi3+ and Sm3+ ions. The photoluminescence (PL) properties of single Bi3+-doped and Bi3+/Sm3+ co-doped Ca2YTaO6 phosphors were fully investigated in terms of PL emission spectrum, emission intensity, energy transfer mechanism, chromaticity coordinate, decay curve, thermal stability, and internal quantum yield. Interestingly, the Ca2YTaO6:0.015Bi3+/0.07Sm3+ phosphor exhibited a high quantum yield (70.71%). Furthermore, the relative sensitivity based on the dual-emission centers (Bi3+ and Sm3+) was also analyzed. It is demonstrated that high-efficiency near-white Ca2YTaO6:Bi3+/Sm3+ phosphor with good sensing properties is expected to be a candidate in the field of optical thermometry.