NaYF4:Sm3+/Yb3+@NaYF4:Er3+/Yb3+ core-shell structured nanocalorifier with optical temperature probe.

A core-shell structure with a NaYF4:Sm3+/Yb3+ core for photothermal conversion nanocalorifier and a NaYF4:Er3+/Yb3+ shell as temperature probe for potential applications in photothermal therapy (PTT) were synthesized by a thermal decomposition technique of rare-earth oleate complexes. The optical temperature reading-out property for the NaYF4:Sm3+/Yb3+@NaYF4:Er3+/Yb3+ core-shell structure was systematically investigated and it was found that in comparison with pure NaYF4:Er3+/Yb3+ particles, the temperature sensing performance of the NaYF4:Er3+/Yb3+ shell did not become worse due to the presence of NaYF4:Sm3+/Yb3+ core. Furthermore, the photothermal conversion behavior for core-shell nanoparticles was successfully examined by dint of temperature sensing of the NaYF4:Er3+/Yb3+ shell, and it was found that an excitation-power-density-dependent temperature increase of up to several tens degrees can be achieved. All the experimental results suggested that the core-shell structure may be an excellent nanocalorifier candidate for advanced temperature-controllable PTT.