Optimization of highly sensitive YAG:Cr³⁺,Nd³⁺ nanocrystal-based luminescent thermometer operating in an optical window of biological tissues

Abstract

Luminescent and temperature sensitive properties of YAG:Cr,Nd nanocrystals were analyzed as a function of temperature, nanoparticle size, and excitation wavelength. Due to numerous temperature-dependent phenomena (e.g. Boltzmann population, thermal quenching, and inter-ion energy transfer) occurring in this phosphor, four different thermometer definitions were evaluated with the target to achieve a high sensitivity and broad temperature sensitivity range. Using a Cr to Nd emission intensity ratio, the highest 3.48% K sensitivity was obtained in the physiological temperature range. However, high sensitivity was compromised by a narrow sensitivity range or vice versa. The knowledge of the excitation and temperature susceptibility mechanisms enabled wise selection of the spectral features found in luminescence spectra for a temperature readout, which enabled the preservation of relatively high temperature sensitivity (>1.2% K max) and extended the temperature sensitivity range from 100 K to 850 K. The size of the nanophosphors had negligible impact on the performance of the studied materials.

In Vivo Subcutaneous Thermal Video Recording by Supersensitive Infrared Nanothermometers

“…According to the level scheme included in Figure , this result suggests that the large thermal sensitivity of 690 nm excited Er‐Yb@Yb‐Tm core/shell NPs is only achieved when the 3 H 5 level of Tm 3+ ions is contributing to the overall emission spectrum and/or when the 3 H 5 (Tm 3+ ); 3 F 5/2 (Yb 3+ ) → 3 H 6 (Tm 3+ ); 3 F 5/2 (Yb 3+ ) ET process is involved. Previous works have demonstrated that the ratiometric thermal sensitivity of rare earth doped NPs is based either on the temperature dependence of ET efficiency between different rare earth ions or on the different temperature quenching rate of the different rare earth ions . In our particular case, both effects could be contributing to the superior ratiometric thermal sensitivity of our Er‐Yb@Yb‐Tm core/shell NPs.…”

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.…”

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

“…As it was recently showed, this is an important condition to enhance the relative sensitivity of this kind of LTs (Marciniak et al, 2017a). In case of Y 3 Al 2 Ga 3 O 12 : Cr 3+ , Nd 3+ (Figure 2D) nanocrystals the presence of Nd 3+ ion significantly quenched the Cr 3+ emission intensity due to the Cr 3+ → Nd 3+ energy transfer.…”

“…One of the most promising one, relies on exploiting transition metal (TM) ions, whose highly temperature dependent emission is referred to emission of barely temperature dependent lanthanides ions (Marciniak et al, 2017a; Drabik et al, 2018; Elzbieciak et al, 2018; Kniec and Marciniak, 2018; Marciniak and Trejgis, 2018; Trejgis and Marciniak, 2018). Materials which could be applied as real time temperature sensors in biomedicine, must also accomplish some other important requirements like sufficient sensitivity to temperature changes, high stability, low cytotoxicity (Brites et al, 2012; Jaque and Vetrone, 2012; Benayas et al, 2015) and operation in spectral range of optical transparency windows of biological tissues (Anderson and Parrish, 1981; Jaque and Jacinto, 2016).…”