Nd:YAG Near-Infrared Luminescent Nanothermometers

In this work, the thermal sensing capability of Nd³⁺-doped Y₃Al₅O₁₂ nanoparticles fabricated by combustion synthesis is reported. Under excitation at 808 nm, the relative intensity of the two spectrally isolated luminescence peaks located at around 940 nm (corresponding to a ⁴F_3/2 →⁴I_9/2 transition of the Nd³⁺ ions) is found to be markedly temperature-dependent allowing for ratiometric luminescence nanothermometry. The potential use of neodymium-doped yttrium aluminum garnet nanoparticles in nanothermometry has been successfully tested in a variety of systems including integrated microelectronics, optofluidic devices, and subtissue ex vivo experiments.