Herein, we investigate the performance of single- and multiparametric luminescence thermometry founded on the temperature-dependent spectral features of Casub.6BaPsub.4Osub.17:Mnsup.5+ near-infrared ...emission. The material was prepared by a conventional steady-state synthesis, and its photoluminescence emission was measured from 7500 to 10,000 cmsup.−1 over the 293-373 K temperature range in 5 K increments. The spectra are composed of the emissions from sup.1E → sup.3Asub.2 and sup.3Tsub.2 → sup.3Asub.2 electronic transitions and Stokes and anti-Stokes vibronic sidebands at 320 cmsup.−1 and 800 cmsup.−1 from the maximum of sup.1E → sup.3Asub.2 emission. Upon temperature increase, the sup.3Tsub.2 and Stokes bands gained in intensity while the maximum of sup.1E emission band is redshifted. We introduced the procedure for the linearization and feature scaling of input variables for linear multiparametric regression. Then, we experimentally determined accuracies and precisions of the luminescence thermometry based on luminescence intensity ratios between emissions from the sup.1E and sup.3Tsub.2 states, between Stokes and anti-Stokes emission sidebands, and at the sup.1E energy maximum. The multiparametric luminescence thermometry involving the same spectral features showed similar performance, comparable to the best single-parameter thermometry.
This paper presents four new temperature readout approaches to luminescence nanothermometry in spectral regions of biological transparency demonstrated on Yb3+/Er3+-doped yttrium aluminum garnet ...nanoparticles. Under the 10 638 cm−1 excitation, down-shifting near infrared emissions (>10 000 cm−1) are identified as those originating from Yb3+ ions' 2F5/2 → 2F7/2 (∼9709 cm−1) and Er3+ ions' 4I13/2 → 4I15/2 (∼6494 cm−1) electronic transitions and used for 4 conceptually different luminescence thermometry approaches. Observed variations in luminescence parameters with temperature offered an exceptional base for studying multiparametric temperature readouts. These include the temperature-dependence of: (i) intensity ratio between emissions from Stark components of Er3+ 4I13/2 level; (ii) intensity ratio between emissions of Yb3+ (2F5/2 → 2F7/2 transition) and Er3+ (4I13/2 → 4I15/2 transition); (iii) band shift and bandwidth and (iv) lifetime of the Yb3+ emission (2F5/2 → 2F7/2 transition) with maximal sensitivities of 1% K−1, 0.8% K−1, 0.09 cm−1 K−1, 0.46% K−1 and 0.86% K−1, respectively. The multimodal temperature readout provided by this material enables its application in different luminescence thermometry setups as well as improved the reliability of the temperature sensing by the cross-validation between measurements.
Judd-Ofelt analysis has been performed from the photoluminescence emission spectra of Y2O3:Eu3+ with 3%, 1% and 0.1% doping concentration and YVO4:Eu3+ with 1% doping concentration, in temperature ...range from 40 °C to 460 °C. For precise calculation, an extended Sellmeier equation that accounts for the doping concentration and temperature dependence of the refractive index of Y2O3 doped with lanthanides is estimated. The temperature dependence of Ω2 and Ω4 parameters are fitted with quadratic and linear regression, respectively. Judd-Ofelt intensity parameters uniformly drop with increasing temperature, but at a different rate for different doping concentrations. From the Judd-Ofelt parameters radiative lifetimes and emission cross-sections were calculated. The cross-sections show a linear decrease with increasing temperature.
•Y2O3 doped with 3%, 1% and 0.1% and YVO4 doped with 1% Eu3+ concentration werecreated.•Photoluminescent spectra were recorded form 40 °C to 460 °C, with 20 °C steps.•Temperature, concentration and wavelength dependent Sellmeier equation is formed.•Ω2,4 parameters were fitted and temperature and concentration dependences established.•Stimulated emission cross-sections and lifetimes temperature dependence is presented.
Front-face synchronous fluorescence spectroscopy combined with chemometrics is used to classify honey samples according to their botanical origin. Synchronous fluorescence spectra of three monofloral ...(linden, sunflower, and acacia), polyfloral (meadow mix), and fake (fake acacia and linden) honey types (109 samples) were collected in an excitation range of 240–500 nm for synchronous wavelength intervals of 30–300 nm. Chemometric analysis of the gathered data included principal component analysis and partial least squares discriminant analysis. Mean cross-validated classification errors of 0.2 and 4.8% were found for a model that accounts only for monofloral samples and for a model that includes both the monofloral and polyfloral groups, respectively. The results demonstrate that single synchronous fluorescence spectra of different honeys differ significantly because of their distinct physical and chemical characteristics and provide sufficient data for the clear differentiation among honey groups. The spectra of fake honey samples showed pronounced differences from those of genuine honey, and these samples are easily recognized on the basis of their synchronous fluorescence spectra. The study demonstrated that this method is a valuable and promising technique for honey authentication.
The figures of merit of luminescence intensity ratio (LIR) thermometry for Er3+ in 40 different crystals and glasses have been calculated and compared. For calculations, the relevant data has been ...collected from the literature while the missing data were derived from available absorption and emission spectra. The calculated parameters include Judd–Ofelt parameters, refractive indexes, Slater integrals, spin–orbit coupling parameters, reduced matrix elements (RMEs), energy differences between emitting levels used for LIR, absolute, and relative sensitivities. We found a slight variation of RMEs between hosts because of variations in values of Slater integrals and spin–orbit coupling parameters, and we calculated their average values over 40 hosts. The calculations showed that crystals perform better than glasses in Er3+-based thermometry, and we identified hosts that have large values of both absolute and relative sensitivity.
Highlights • Cyto- and genotoxicity of FIT monomer and Lucirin TPO photoinitiator were evaluated. • FIT showed less cytotoxic and genotoxic effects than BisGMA. • TPO showed 7 times higher ...cytotoxicity than CQ. • Components of FIT-based mixtures exhibited an antagonistic cytotoxic effect. • Components of BisGMA-based mixtures showed a synergistic cytotoxic effect.
This paper presents four new temperature readout approaches to luminescence nanothermometry in spectral regions of biological transparency demonstrated on Yb
/Er
-doped yttrium aluminum garnet ...nanoparticles. Under the 10 638 cm
excitation, down-shifting near infrared emissions (>10 000 cm
) are identified as those originating from Yb
ions'
F
→
F
(∼9709 cm
) and Er
ions'
I
→
I
(∼6494 cm
) electronic transitions and used for 4 conceptually different luminescence thermometry approaches. Observed variations in luminescence parameters with temperature offered an exceptional base for studying multiparametric temperature readouts. These include the temperature-dependence of: (i) intensity ratio between emissions from Stark components of Er
I
level; (ii) intensity ratio between emissions of Yb
(
F
→
F
transition) and Er
(
I
→
I
transition); (iii) band shift and bandwidth and (iv) lifetime of the Yb
emission (
F
→
F
transition) with maximal sensitivities of 1% K
, 0.8% K
, 0.09 cm
K
, 0.46% K
and 0.86% K
, respectively. The multimodal temperature readout provided by this material enables its application in different luminescence thermometry setups as well as improved the reliability of the temperature sensing by the cross-validation between measurements.
To develop novel luminescent materials for optical temperature measurement, a series of Yb3+- and Er3+-doped Ca3Sc2Si3O12 (CSS) upconversion (UC) phosphors were synthesized by the sol–gel combustion ...method. The crystal structure, phase purity, and element distribution of the samples were characterized by powder X-ray diffraction and a transmission electron microscope (TEM). The detailed study of the photoluminescence emission spectra of the samples shows that the addition of Yb3+ can greatly enhance the emission of Er3+ by effective energy transfer. The prepared Yb3+ and Er3+ co-doped CSS phosphors exhibit green emission bands near 522 and 555 nm and red emission bands near 658 nm, which correspond to the 2H11/2→4I15/2, 4S3/2→4I15/2, and 4F9/2→4I15/2 transitions of Er3+, respectively. The temperature-dependent behavior of the CSS:0.2Yb3+,0.02Er3+ sample was carefully studied by the fluorescence intensity ratio (FIR) technique. The results indicate the excellent sensitivity of the sample, with a maximum absolute sensitivity of 0.67% K−1 at 500 K and a relative sensitivity of 1.34% K−1 at 300 K. We demonstrate here that the temperature measurement performance of FIR technology using the CSS:Yb3+,Er3+ phosphor is not inferior to that of infrared thermal imaging thermometers. Therefore, CSS:Yb3+,Er3+ phosphors have great potential applications in the field of optical thermometry.
The multiparametric luminescence thermometry with Dy3+, Cr3+ double activated yttrium aluminium garnet – YAG is demonstrated. Phospors were synthesized via Pechini method and their structure is ...confirmed by X-ray diffraction analysis. Mean crystallite size of powders was calculated to be ~22 nm. Morphology was investigated using scanning electron microscopy showing combination of dense, different size chunks constituted of spherical particles bellow 50 nm in size. Photoluminescence emission spectra of the Dy3+, Cr3+ double activated YAG consist of blue and yellow Dy3+ emissions and the broad, deep red Cr3+ emission. The decrease in the Dy3+ emission intensity with the increase in the Cr3+ content indicates the efficient energy transfer from Dy3+ to Cr3+ of ~90%. Temperature-dependant photoluminescence emission measurements are performed under 484 nm and 582 nm excitation in the steady-state domain and in the 175 K–650 K temperature range. The noted alterations of luminescence with temperature present an excellent base for studying the multiparametric temperature readouts. The luminescence intensity ratio, the most frequently exploited luminescent thermometry temperature readout method, was tested using: i) the combination of Dy3+ and Cr3+ emissions, ii) using the double excitation approach, and iii) using Cr3+ emission only, with relative sensitivities of 0.64 %K−1 at 175 K, 0.96 %K−1 at 200 K and 2.2 %K−1 at 200 K, respectively.
Display omitted
•Multiparametric luminescence thermometry with Dy3+, Cr3+ double activated YAG.•PL consists of blue and yellow Dy3+ emissions and the broad, deep red Cr3+ emission.•Efficient energy transfer (~90%) from Dy3+ to Cr3+ in theYAG host.•LIR using: i) Dy3+ and Cr3+ emissions, ii) double excitation, and iii) Cr3+ emission.•Sr of i) 0.64 %K−1 at 175 K, ii) 0.96 %K−1 at 200 K and iii) 2.2 %K−1 at 200 K.
PDF
