Multi-mode ratiometric thermometry using thermo-intensified NIR emission

Luminescence ratiometric thermometry has enabled fast-responsive and non-invasive temperature detection in microelectronic devices and biological systems, but it still suffers from limited thermal sensitivity and serious thermal quenching effects. Herein, a facile hydrothermal method was developed to construct monodispersed candy-like NaY(MoO4)2:Yb3+/Nd3+micro-thermometers that exhibit efficient near-infrared anti-stokes lumi-nescence under 980 nm excitation. By leveraging active lattice phonon, phonon-assisted Yb3+-> Nd3+energy transfer and excited-state absorption of Nd3+were greatly promoted as the temperature elevated, resulting in a giant and reversible enhancement of 4F7/2, 4S3/2 -> 4I11/2 transition by around 1683-folds. Luminescence in-tensity ratios of these near-infrared emissions featured a strong thermal response under the excitation of 980 and 808 nm, enabling the multi-mode thermometry with high sensitivity and resolution (Sr =4.69% K1 and delta T =0.071 K at 303 K). A flexible thermometer was further fabricated by embedding as-prepared microcrystals into the thin-film substrate, offering precise multi-mode thermal monitoring at the local hotspot in the electronic component.