AUTHOR=Elzbieciak Karolina , Marciniak Lukasz 

TITLE=The Impact of Cr3+ Doping on Temperature Sensitivity Modulation in Cr3+ Doped and Cr3+, Nd3+ Co-doped Y3Al5O12, Y3Al2Ga3O12, and Y3Ga5O12 Nanothermometers

JOURNAL=Frontiers in Chemistry

VOLUME=6

YEAR=2018

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2018.00424

DOI=10.3389/fchem.2018.00424

ISSN=2296-2646

ABSTRACT=<p>A new approach to enhance the sensitivity of transition metal ion based nanocrystalline luminescent thermometer is presented. It was shown that the increase of Cr<sup>3+</sup> concentration in three types of garnet host namely Y<sub>3</sub>Al<sub>5</sub>O<sub>12</sub>, Y<sub>3</sub>Ga<sub>5</sub>O<sub>12</sub>, and Y<sub>3</sub>Al<sub>2</sub>Ga<sub>3</sub>O<sub>12</sub> allows for significant enhancement of their performance in non-contact thermometry. This phenomenon is related to the weakening of the crystal field strength due to enlargement of average Cr<sup>3+</sup>-O<sup>2−</sup> distance at higher Cr<sup>3+</sup> concentrations. By increasing Cr<sup>3+</sup> concentration from 0.6 to 30%, the sensitivity increased by over one order of magnitude from <italic>S</italic> = 0.2%/°C to <italic>S</italic> = 2.2%/°C at 9°C in Y<sub>3</sub>Al<sub>2</sub>Ga<sub>3</sub>O<sub>12</sub> nanocrystals. Moreover, it was found that due to the Cr<sup>3+</sup> → Nd<sup>3+</sup> energy transfer in the Cr<sup>3+</sup>, Nd<sup>3+</sup> co-doped system, the usable Cr<sup>3+</sup> concentration, for which its emission can be detected, is limited to 10% while the sensitivity at −50°C was doubled (from 1.3%/°C for Y<sub>3</sub>Al<sub>2</sub>Ga<sub>3</sub>O<sub>12</sub>:10%Cr<sup>3+</sup> to 2.2%/°C Y<sub>3</sub>Al<sub>2</sub>Ga<sub>3</sub>O<sub>12</sub>:10%Cr<sup>3+</sup>, 1%Nd<sup>3+</sup> nanocrystals).</p>