Simultaneously excellent upconversion luminescence and temperature sensing properties in tungstate multiphase phosphors

For optical temperature sensor, high luminescence intensity is as important as high temperature sensing sensitivity. In this work, research on rare-earth ions Er3+/Yb3+ codoped KY(WO4)2–K2WO4 multiphase phosphors for optical temperature sensing application was first proposed by material design. Under a 980 nm excitation, the upconversion luminescence intensity of multiphase materials was much higher than that of pure phase materials. For the 0.6KYW–0.4KW multiphase material, excellent temperature sensing property that the maximal sensitivity was 14.7 × 10− 3 K−1 at 643 K in a broad temperature range from 83 to 663 K was simultaneously obtained. These results indicate that KY(WO4)2–K2WO4 multiphase phosphors with excellent upconversion luminescence and temperature sensing properties are promising candidates for optical temperature sensors.