Sensitivity augmentation in multimodal optical thermometry based on NaBi (MoO4)2:Yb3+,Er3+@NaBi(MoO4)2:Yb3+,Ho3+ core@shell nanoparticles

Abstract

High relative temperature sensitivity (S_r) and a broad sensing range are now necessities in real-world applications of lanthanide luminescence thermometry. A luminescent thermometer that is composed of core@shell Ln³⁺-doped molybdates (Ln = Yb, Er, and Ho) is suggested here. The material under consideration here, NaBi(MoO₄)₂:Yb³⁺,Er³⁺@NaBi(MoO₄)₂:Yb³⁺,Ho³⁺ core@shell nanoparticles, has been synthesized via an ethylene glycol-mediated solvothermal procedure, and the temperature dependencies based on the varied emissions in the green and red regions have been evaluated. The successful synthesis of the core@shell has been clarified via particle size measurement as well as enhancement in photoluminescence intensity. The findings of the experiment show that NaBi(MoO₄)₂:Yb³⁺,Er³⁺@NaBi(MoO₄)₂:Yb³⁺,Ho³⁺ core@shell nanoparticles have a relative temperature sensitivity of 4.16% K⁻¹ at 350 K and a low temperature uncertainty of <0.1 K. In addition, it outperforms previously reported luminescent thermometric materials in maintaining a reasonably high S_r (no lower than 2.5% K⁻¹) throughout a broad temperature sensing range (∼200 K). The findings of this work may, therefore, shed light on a promising avenue for future research into the construction of highly accurate luminescent thermometers capable of measuring a broad variety of temperatures.