Temperature sensing characteristics of Bi3+/Eu3+ co-activated SrGa2B2O7: Phosphor for dual-mode optical thermometry

SrGa2B2O7: Bi3+, Eu3+ phosphors were synthesized through high temperature solid-state method successfully. The structure, luminescent characteristics and temperature sensing properties of the phosphors are studied. Under the excitation at 363 nm, several bands of Sr0.935Ga2B2O7: 0.015Bi3+, 0.05Eu3+ phosphor appeared in the blue and red regions and the emission peaks of Bi3+ and Eu3+ ions can be well separated. For the SrGa2B2O7: Bi3+/Eu3+ samples, the maximum absolute temperature sensitivity (Sa) reaches about 0.181 K−1 at 473 K and the relative temperature sensitivity (Sr) of that is up to 1.549% K−1 at 423 K. The results originated from the characteristic transitions of Bi3+ (3P1→1S0) and Eu3+ (5D0→7F1, 5D0→7F2, 5D0→7F4) ions are based on the fluorescence intensity ratio (FIR). Furthermore, the maximum of Sa is 4.66 K−1 and the maximum of Sr is 0.538% K−1 at 293 K based on the fluorescence lifetime temperature measurement method. All these investigations indicate that the SrGa2B2O7: Bi3+/Eu3+ phosphors can be a promising optical thermometric material in the field of temperature sensing.