Fluorescence Intensity Ratio‐based temperature sensor with single Nd<sup>3 +</sup> :Y<sub>2</sub>O<sub>3</sub> nanoparticles: Experiment and theoretical modeling
Rodrigo Galvão, Luiz Fernando dos Santos, Rogéria Rocha Gonçalves, Leonardo de S. Menezes
Abstract
Abstract A thermometer based on single Nd 3 + :Y 2 O 3 nanoparticles is reported. The nanothermometer relies on the ratio of thermally coupled Nd 3 + emission lines accessible by either continuous‐wave upconversion under 880 nm or downconversion under 532 nm excitation wavelengths. Both processes are modeled through rate equation systems based on multiphonon interactions between excited luminescent states, which led to excellent agreement with the experimental data. Moreover, the Y 2 O 3 effective phonon mode energy was determined, showing the appropriateness of the theoretical approach used. The system presented a relative sensitivity up to 1.36% at 300 K while working within the first biological window, thus particularly useful for biological sensing applications.