Energy transfer in dual-emission LiY6(BO3)3O5: Bi3+, Eu3+ phosphors for temperature sensing applications

In this work, a Bi 3+ and Eu 3+ co-doped borate oxide LiY 6 (BO 3 ) 3 O 5 (LYBO) phosphor was prepared using high temperature solid-state method. Eu 3+ can be well sensitized by Bi 3+ in the LYBO matrix under 305 nm excitation and produce well-separated emission bands with high intensity. The energy transfer from Bi 3+ to Eu 3+ results in the tunable multicolor emission from LYBO. The maximum energy transfer efficiency can reach 95.93 %. The Bi 3+ and Eu 3+ emissions exhibit the differentiated responses to thermal quenching. The fluorescence intensity ratios between 615 nm and 421 nm show a favorable linear relationship in the range of 123–483 K. It indicates the outstanding optical thermometry performance of LYBO: Bi 3+ , Eu 3+ . The maximum absolute sensitivity (S a ) and relative sensitivity (S r ) are determined to be 0.0087 K -1 and 3.84 % K −1 , respectively. The results exhibit that LYBO: Bi 3+ , Eu 3+ phosphor has a promising application as an optical thermometer in non-contact temperature measurement.