Facile precipitation synthesis of green-emitting BaY2F8:Yb3+, Ho3+ upconverting phosphor

Upconversion process in BaY2F8:Yb3+,Ho3+ phosphor for optical thermometry

“…The phase formation and purity of the BaY 2 F 8 :0.2Yb 3+ ,0.02Ho 3+ phosphor has already been discussed using the powder X‐ray diffraction pattern (PXRD). [ 7 ] As observed in Figure 1, it was obvious from the PXRD that the BaY 2 F 8 :0.2Yb 3+ , 0.02Ho 3+ phosphor had formed in a single phase and there was no trace of any kind of impurity phase due either to unreacted precursors or to dopant lanthanides.…”

“…XRD pattern of BaY 2 F 8 :0.2Yb 3+ , 0.02Ho 3+ phosphor along with the standard XRD pattern (reproduced with permission from ref. [ 7 ] , copyright © 2019 Elsevier)…”

“…From the upconversion photoluminescence (UCPL) analysis, it was discovered that BaY 2x‐y F 8 : y Yb 3+ , x Ho 3+ phosphor exhibited green luminescence with emission peaks at 538 nm and 549 nm due to 5 F 4 → 5 I 8 and 5 S 2 → 5 I 8 transitions, respectively. [ 7 ] The optimum dopant concentrations that provided the maximum green luminescence were found to be y = 0.2 and x = 0.02 for Yb 3+ and Ho 3+ , respectively. Hence, the BaY 2 F 8 :0.2Yb 3+ , 0.02Ho 3+ phosphor was chosen to study the variation in the UCPL emission spectra with temperature for optical thermometry application.…”

“…Details of the synthesis have been described previously. [ 7 ] All metal ion nitrate solutions were sequentially into a glass beaker placed on a hotplate. The solutions were kept stirring using a magnetic needle to form a uniform clear solution.…”

“…The UC luminescence properties of this phosphor have been discussed previously. [ 7 ] However, the capability of this phosphor for optical thermometry was not analysed and, hence, the FIR of the transitions from the TCEL, 5 F 4 and 5 S 2 levels, to the ground state 5 I 8 of Ho 3+ in the BaY 2 F 8 :0.2Yb 3+ , 0.02Ho 3+ phosphor are presented and discussed here.…”