Dual-emitting SrY2O4:Bi3+,Eu3+ phosphor for ratiometric temperature sensing

A promising temperature sensing material of SrY2O4:Bi3+,Eu3+ (SYO:Bi3+,Eu3+) phosphor was successfully synthesized here. Its structure, luminescence, thermal-sensitive emission behaviors as well as the probable mechanism were investigated in detail. Dual-emitting centers with well separated emission bands were obtained in SYO:Bi3+,Eu3+ phosphor, presenting excellent signal discriminability. Benefited from the opposite temperature dependence of Bi 3+ and Eu 3+ luminescent intensities in SYO matrix, highly relative sensitivity of 0.86% K(-1 )at 433 K and absolute sensitivity of 4.33% K-1 at 563 K based on the fluorescence intensity ratio between Bi3+ and Eu3+ were attained. More importantly, the obvious variety of the luminescent color from red at room temperature to blue at 563 K was realized, which is easily distinguished by the human eyes. These results manifest that the as-obtained SYO:Bi3+,Eu3+ phosphor is a promising candidate for application in optical temperature sensors covering a broad temperature range from 313 to 563 K and acts as a safety sign in high-temperature environments.