A three-mode optical thermometry based on thermochromic Gd2GaSbO7:Bi3+,Eu3+ phosphors

Abstract

Nowadays, multi-mode luminescent thermometry has emerged as a strongly promising noncontact temperature-sensing technique, in which can realize the temperature determination more reliable and accurate by incorporating the excellent temperature monitoring properties from different modes of sensing. Herein, three-mode optical thermometry technics were triumphantly designed in thermochromic Gd2GaSbO7 (GGS):Bi3+,Eu3+ phosphors. With ascending temperature, the emission color of GGS:Bi3+,Eu3+ varies remarkably from pink to yellow with the thermo-caused chromaticity shift reaching 0.2505, being easily differentiated by our eyes. Employing the fluorescence intensity ratio of well-separated emission bands of Bi3+ and Eu3+, outstanding relative sensitivity (SR) of 1.03% K-1, favorable temperature uncertainty of 0.296 K, excellent reversibility and repeatability are acquired. Moreover, profiting by the rapid decline of fluorescence decay lifetime of Bi3+ (3P1) in GGS:Bi3+,Eu3+ with temperature elevating, the optimal SR reaches 0.75% K-1 at 473 K, higher than most reported optical thermometers. These discoveries indicate that GGS:Bi3+,Eu3+ phosphors have fantastic prospects in multi-mode temperature detection and high temperature warning areas.