Tb3+/Mn2+ singly/doubly doped Sr3Ce(PO4)3 for multi-color luminescence, excellent thermal stability and high-performance optical thermometry

Abstract

A series of Tb3+ and Mn2+ singly/dually doped Sr3Ce(PO4)3 (SCP) phosphors were successfully synthesized via gel-combustion, whose structure, temperature-dependent photoluminescence (298-573 K), thermal stability, energy transfer, and performance of optical thermometry were systematically investigated. The phosphors were demonstrated to have thermal stability increasing in the order SCP:0.15Mn2+ < SCP < SCP:0.2Tb3+/0.2Mn2+ < SCP:0.4Tb3+ for the four typical compositions. SCP:0.4Tb3+ exhibited zero-thermal-quenching in the studied temperature range, and application indicated that SCP:0.15Tb3+/0.05Mn2+ can be a warm-white phosphor for UV-excited LEDs. While SCP:0.15Mn2+ is not suitable for ratiometric temperature sensing, both SCP:0.4Tb3+ and SCP:0.2Tb3+/0.2Mn2+ were shown to be excellent phosphors for self-referencing optical thermometry. The SCP:0.4Tb3+ phosphor presented absolute (SA) and relative (SR) sensitivities of ∼3.90% (573 K) and 0.384% K−1 (298 K), respectively, repeatability factor of ∼99%, and minimum temperature resolution of ∼0.078 K with the ITb/ICe fluorescence intensity ratio (FIR). The SCP:0.2Tb3+/0.2Mn2+ phosphor, on the other hand, showed maximum SA and SR values of ∼1.62% K−1 (573 K) and 0.612% K−1 (298 K), respectively, repeatability factor of ∼99%, and minimum temperature resolution of ∼0.049 K with the ITb/IMn FIR. Multi-color luminescence was also achieved via manipulating activator concentration and through efficient energy transfer among Ce3+, Tb3+ and Mn2+.