Electric polarization-enhanced optical thermometry in lanthanide ion-doped ferroelectric Bi₄Ti₃O₁₂ nanosheets

The demand for temperature measurement in optoelectronic integration has prompted research on advanced luminescent materials. Here, ferroelectric Bi₄Ti₃O₁₂:Yb³⁺/Er³⁺/Nd³⁺ nanosheets were designed for optical thermometry. The transition emissions of nanosheets were significantly enhanced through electric polarization engineering. By utilizing the fluorescence intensity ratio of emissions from Nd³⁺ and Er³⁺ ions, the poled system achieved notable absolute and relative sensing sensitivities of 3.03 and 2.52% K^-1, respectively. These results highlight the multi-band luminescence and optoelectronic coupling characteristics of lanthanide ion-doped ferroelectric nanosheets and suggest that electric field polarization-enhanced temperature measurement can serve a reference for enhancing optical sensing capabilities.