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 4F3/2 →4I9/2 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.