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Lanthanide ions (Ln3+)-activated nanomaterials have been intensively explored as nanothermometers (NTMs) that can be used as optical thermal probes in various fields.[1] For instance, Ln3+ doped upconversion(UC) NTMs, such as Tm3+/Yb3+ co-doped CaF2 nanoparticles, have been employed to evaluated the temperature of the biological systems based on the ratio of the UC emission intensity from different thermally populated 4f levels under near infrared (NIR) irradiation.However, these NTMs still suffer the common inherent drawbacks of a low temperature resolution which hinder their bio-applications.[2] Therefore, higher temperature sensitivity is preferred based on emission bands from different ions,which has been demonstrated with e.g.Eu3+-Tb3+ co-doped metal organic frameworks (MOFs) with a higher sensitivity.[3] Since these MOFs are not penetrable to tissue cells and only UV excitable, they are still not suitable for applications in biological fields.To circumvent these problems, we design here a self-referencing NIR-excitable NTM based on lanthanide-doped core-shell nanostructure.We demonstrate that non-contact self-referencing temperature sensors can be realized with this design.These lanthanide-based nanothermometers (NaGdF4∶yb3+/Tm3+@Tb3+/Eu3+) exhibit higher sensitivity at a wide range from 125 to 300 K based on two emissions of Tb3+ at 545 nm and Eu3+ at 615 nm under NIR laser excitation.Moreover, their small size and adjustable surface chemistry endow them high performance in nanoscale environment with good spatial and temperature resolution.