Multiphonon assisted upconversion thermal enhancement for optical temperature sensing and high penetration depth

Toward Ultra-High Sensitivity Optical Thermometers and Bright Yellow LEDs Based on Phonon-Assisted Energy Transfer in Rare Earth-Doped La2ZnTiO6 Double Perovskite

“…Conventional temperature measurement methods are becoming obsolete due to drawbacks such as the inability to measure under extreme conditions, the inability to measure moving objects, and the need for prolonged contact. Therefore, luminescence intensity ratio (LIR) thermometry based on Ln 3+ -doped luminescent materials is widely favored for its advantages of self-referencing, fast response, high temperature resolution, no need for contact, and suitability for extreme conditions. − Current LIR-based temperature sensing techniques are mainly classified into two types: thermally coupled levels (TCLs) temperature measurement and nonthermally coupled levels (NTCLs) temperature measurement. − Regardless of the type of thermometer, the relative sensitivity is the most important parameter to judge its temperature measurement performance. TCLs are those where the energy gap between the two energy levels is in the range of 200 to 2000 cm –1 and where the change in the distribution of particles with temperature is in accordance with Boltzmann’s law.…”

Convolutional neural networks driving thermally enhanced upconversion luminescence for temperature sensing: achieving high accuracy and robustness across a wide temperature range

“…15,16 And the phonon-assisted absorption of excitation is also meaningful for weakening the thermal-induced luminescence quenching. 17 In our previous studies, the phonon-assisted energy transfer (PAET) mechanism between RE ions was employed to achieve thermally enhanced luminescence. 18 The intense emission of RE ions at high temperature is particularly beneficial to the good signal-to-noise ratio and enables luminescence thermometry to work in a large temperature region.…”