Thermometer design at the nanoscale

Accurate temperature measurement with high spatial resolution is a challenging research topic. Advances in nano- and biotechnology demand precise thermometry down to the nanoscale regime, where conventional methods are not able to make measurements. The development of a nanoscale thermometer is not only a matter of size, but also requires materials with novel physical properties, because all physicochemical and thermodynamic properties are drastically altered at this tiny scale. We review current technical developments toward nanoscale thermometries and describe their advantages and applications. In particular, progress on thermal sensors using molecular and biological moieties, as well as nanoscale superstructures, is stressed as a novel approach to thermometry.