BaMoO4:Nd3+-Yb3+ upconverting phosphors for NIR to NIR contactless temperature reading out

BaMoO4:Nd3+-Yb3+ phosphors have been synthesized by using conventional solid state reaction synthesis technique. Frequency up-conversion (UC) emission studies have been performed under 980 nm excitation. The developed UC phosphors show multicolor upconverted emission bands in the 400-900 nm wavelength range and assigned via the radiative transitions of Nd3+ ion. FIR technique based on frequency upconversion has been applied for the F-4(7/2) -> I-4(9/2) and F-4(5/2) -> I-4(9/2) transitions of Nd3+ ion in the NIR (750-804 nm) region arising from the two thermally coupled energy states. The energy gap (Delta E) between the upper and lower excited levels (F-4(7/2) and F-4(5/2)) was found to be similar to 800 cm(-1). The maximum sensor sensitivity similar to 23.2 x 10(-4) K-1 at 306 K (operating temperature range 306-483 K) under 980 nm NIR laser irradiation for BaMoO4:Nd3+-Yb3+ phosphors is reported. The prepared phosphors have proven their utility as a novel upconverting material for NIR to NIR contactless temperature reading out.