Optical super-resolution nanothermometry via stimulated emission depletion imaging of upconverting nanoparticles.

From engineering improved device performance to unraveling the breakdown of classical heat transfer laws, far-field optical temperature mapping with nanoscale spatial resolution would benefit diverse areas. However, these attributes are traditionally in opposition because conventional far-field optical temperature mapping techniques are inherently diffraction limited. Optical super-resolution imaging techniques revolutionized biological imaging, but such approaches have yet to be applied to thermometry.

Luminescence Thermometry Beyond the Biological Realm.

As the field of luminescence thermometry has matured, practical applications of luminescence thermometry techniques have grown in both frequency and scope. Due to the biocompatibility of most luminescent thermometers, many of these applications fall within the realm of biology. However, luminescence thermometry is increasingly employed beyond the biological realm, with expanding applications in areas such as thermal characterization of microelectronics, catalysis, and plasmonics.

Nanothermometry in rarefied gas using optically levitated nanodiamonds.

Heat transfer in gases in the continuum regime follows Fourier's law and is well understood. However, it has been long understood that in the subcontinuum, rarefied gas regime Fourier's law is no longer valid and various models have been proposed to describe heat transfer in these systems. These models have very limited experimental exploration for spherical geometries due to the difficulties involved.

Apparent self-heating of individual upconverting nanoparticle thermometers.

Individual luminescent nanoparticles enable thermometry with sub-diffraction limited spatial resolution, but potential self-heating effects from high single-particle excitation intensities remain largely uninvestigated because thermal models predict negligible self-heating. Here, we report that the common "ratiometric" thermometry signal of individual NaYF:Yb,Er nanoparticles unexpectedly increases with excitation intensity, implying a temperature rise over 50 K if interpreted as thermal. Luminescence lifetime thermometry, which we demonstrate for the first time using individual NaYF:Yb,Er nanoparticles, indicates a similar temperature rise.

Nanocarbon Paper: Flexible, High Temperature, Planar Lighting with Large Scale Printable Nanocarbon Paper (Adv. Mater. 23/2016).

On page 4684, C. Dames, L. Hu and co-workers report highly efficient, broadband lighting from printed hybrid nanocarbon structures with carbon nanotubes and reduced graphene oxides.