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

Abstract

A new approach to enhance the sensitivity of transition metal ion based nanocrystalline luminescent thermometer is presented. It was shown that the increase of Cr3+ concentration in three types of garnet host namely Y3Al5O12, Y3Ga5O12, and Y3Al2Ga3O12 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 Cr3+-O2− distance at higher Cr3+ concentrations. By increasing Cr3+ concentration from 0.6 to 30%, the sensitivity increased by over one order of magnitude from S = 0.2%/°C to S = 2.2%/°C at 9°C in Y3Al2Ga3O12 nanocrystals. Moreover, it was found that due to the Cr3+ → Nd3+ energy transfer in the Cr3+, Nd3+ co-doped system, the usable Cr3+ 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 Y3Al2Ga3O12:10%Cr3+ to 2.2%/°C Y3Al2Ga3O12:10%Cr3+, 1%Nd3+ nanocrystals).

LiAl5O8:Fe3+ and LiAl5O8:Fe3+, Nd3+ as a New Luminescent Nanothermometer Operating in 1st Biological Optical Window

“…As a consequence, nonradiative decay can only occur via multiphonon relaxation, which has a much lower probability to take place. The spectroscopic properties of some transition metal ions, Cr 3+ , Mn 2+/3+/4+ , V 3+/4+/5+ , Co 2+ , Ti 3+/4+ [6,[13][14][15][16][17][18][19][20] have been already considered for non-contact temperature sensing. However, Fe 3+ has not been considered for this purpose.…”

Synergy between NIR luminescence and thermal emission toward highly sensitive NIR operating emissive thermometry

“…Due to low scattering and absorption of the light by the tissue, near infrared (NIR) spectral range, where optical transparency windows of tissues occur, is especially desirable to report temperature dependent spectral signatures. Up to date many different phosphors have been proposed as NIR emitting noncontact temperature sensors including: quantum dots [17][18][19] , silicon nanoparticles 20 , nanogels 21 , inorganic nanoparticles doped with lanthanide ions [22][23][24][25][26][27][28] or transition metal ions [29][30][31][32][33][34] , nanodiamonds 35 , metal-organic frameworks 36 , coordination polymers 37 , semiconductor nanoparticles 38 etc. The progress in luminescence based thermometry, is strongly related to the advancement in available materials, especially because low intensity NIR emission of the phosphors inevitably increases the uncertainty of the temperature determination.…”

Synthesis, Cytotoxicity Assessment and Optical Properties Characterization of Colloidal GdPO4:Mn2+, Eu3+ for High Sensitivity Luminescent Nanothermometers Operating in the Physiological Temperature Range

“…In the case of biological applications, LT needs to reveal high sensitivity to temperature changes in the physiological temperature range (20-50 • C). Moreover, in order to enhance the accuracy and reliability of temperature sensing by the minimization of the light scattering and absorption by the tissue, emission of such phosphors should spectrally fall into biological optical windows (BWs) (BW-I: 650-950 nm, BW-II: 1000-1350 nm, and BW-III: 1500-1800 nm) [15][16][17][18][19][20][21]. Therefore, many potential non-invasive nanothermometers such as YAG garnets [22], NaYF 4 fluorides [23], Au NPs [24], etc., doped with optical active ions operating in the range of BWs have been studied in the last few years.…”