All-Optical Thermometry with Nitrogen-Vacancy Centers in Nanodiamond-Embedded Polymer Films

Fluorescent nanodiamonds (FNDs) containing negatively charged nitrogen-vacancy (NV-) centers are applicable for nanoscale temperature sensing in frontier areas of science and engineering. As researchers take advantage of the unique chemical and physical properties of this nanomaterial, many new innovations are emerging. Here, we show that FNDs can be readily embedded in poly(2-hydroxyethyl methacrylate) (PHEMA) with a high density (1 X 10(11) particles in a film of 10 X 10 X 0.1 mm(3)) and a high uniformity (intensity variation of similar to 10% over a distance of 10 mu m). The FND-embedded polymer films can be fabricated in large scale and are useful as all -optical thermometers for practical applications. This work made a comparative study on the temperature dependence of the peak positions and heights of the zero phonon line (ZPL) of NV- centers in these films from 35 to 120 degrees C. A measurement sensitivity of 0.46-1.1 and 0.15-0.62 K Hz(-1/2) was achieved respectively for the ZPL shifts and height changes over this temperature range. The utility and versatility of this device were demonstrated with a study for the energy transfer kinetics of a resistively heated gold microwire embedded in the PHEMA film.