Coupled Energy Levels Research Articles

Construction of self-sensitized NaErF4@NaYF4 nanoparticles with multiple red upconversion luminescence for highly-sensitive optical temperature sensing

Efficient deep-penetrating red upconversion luminescent nanoparticles with ultra-small size are promising biological temperature probes. Herein, bright red upconversion luminescence are achieved in NaErF4@NaYF4 core-shell nanoparticles under multi-wavelength excitation of 808 nm, 980 nm, and 1550 nm. The core-shell structure engineering is constructed to minimize energy dissipation by surface quenchers. Furthermore, the established model explains the temperature dependence of thermally coupled energy levels in detail, confirming that the non-radiative relaxation is responsible for the quenching processes. Based on the luminescence intensity ratio technique, optical temperature sensing characteristics of thermally coupled (2H11/2/4S3/2) and non-thermally coupled energy levels (4F9/2/4S3/2) are investigated under the excitation of a relatively safe near-infrared wavelength for 1550 nm. The thermometer can maintain a maximum sensitivity of 35 × 10−3 K−1 over the entire temperature measurement region by fitting the non-thermally coupled energy levels, which is conducive to temperature monitoring in vivo due to high sensitivity and relatively safe excitation wavelength.

High-sensitivity NaYF4:Yb3+/Ho3+/Tm3+ phosphors for optical temperature sensing based on thermally coupled and non-thermally coupled energy levels.

Non-contact optical temperature sensors are highly sought after by researchers due to their satisfactory temperature resolution (δ(T) < 0.1 °C), high relative thermal sensitivity (Sr > 1% °C-1), fast temporal response (t < 0.1 s), and long-term optical stability. In this study, NaYF4:Yb3+/Ho3+/Tm3+ upconversion nanoparticles were prepared by a solvothermal method, and their crystal structure, microscopic morphology, and luminescence mechanism, together with the temperature sensing properties of the specimens, were investigated. Under 980 nm laser excitation, the specimens exhibited strong upconversion luminescence, and the emission peaks corresponded to the characteristic energy level jumps of Ho3+ and Tm3+, respectively. The temperature-dependent luminescence spectra of the samples were investigated based on the fluorescence intensity ratio (FIR) technique over a temperature gradient of 295-495 K. The samples are based on thermally coupled energy levels (TCLs: 1G4(1,2) → 3H6(Tm3+)) and non-thermally coupled energy levels (NTCLs: 3F3 → 3H6(Tm3+) and 5F3 → 5I8(Ho3+), 3F3 → 3H6(Tm3+) and 1G4 → 3H6(Tm3+), 3F3 → 3H6(Tm3+) and 5F5 → 5I8(Ho3+), 3F3 → 3H6(Tm3+) and 5F4 → 5I8(Ho3+)) for temperature sensing performance. The maximum absolute sensitivity (Sa), relative sensitivity (Sr), and minimum temperature resolution δ(T) were found to be 0.0126 K-1 (495 K), 1.7966% K-1 (345 K), and 0.0167 K, respectively, which are better than those of most sensing materials, and the simultaneous action of multiple coupling energy levels can further improve the temperature precision. This study indicates that the sample has a good value for optical temperature measurement and also provides new ideas for the exploration of other high-quality optical temperature sensing materials.

An up-conversion Ba3In(PO4)3:Er3+/Yb3+ phosphor that enables multi-mode temperature measurements and wide-gamut 'temperature mapping'.

At present, most fluorescent materials that can be used for optical temperature measurement exhibit poor thermochromic performance, which limits their applications. In this study, the phosphor Ba3In(PO4)3:Er/Yb was synthesized with a high doping concentration of Yb3+, and it emitted composition- and temperature-induced wide color gamut up-conversion luminescence from red to green. Four modes of fluorescence thermometry can be realized in the temperature range of 303-603 K, which is based on the ratio of fluorescence intensity between thermally coupled energy levels and non-thermally coupled energy levels, color coordinate shift, and fluorescence decay lifetime, respectively. The highest Sr value obtained was 0.977% K-1. Taking advantage of the fact that temperature can significantly change the luminous color of the phosphor Ba3In(PO4)3:0.02Er3+/0.05Yb3+, we demonstrated 'temperature mapping' on a smooth metal surface with multiple optical encryptions. These results indicate that the Ba3In(PO4)3:Er/Yb phosphor is an excellent fluorescent material for thermal imaging and has great application potential in temperature visualization measurement and optical encryption.

Impact of crystal structure on optical properties and temperature sensing behavior of NaYF4:Yb3+/Er3+ nanoparticles.

We report a comprehensive study of the structural, morphological, and optical properties, and UC-based ratiometric temperature sensing behavior of (α) cubic and (β) hexagonal phases of NaYF4:Yb3+/Er3+ nanoparticles. The α-NaYF4:Yb3+/Er3+ and β-NaYF4:Yb3+/Er3+ nanoparticles were synthesized using co-precipitation and hydrothermal methods, respectively. Powder X-ray diffraction studies confirmed the phase purity of the samples. The morphological studies show uniform particle sizes of both phases; the average particle size of α-NaYF4:Yb3+/Er3+ and β-NaYF4:Yb3+/Er3+ was 9.2 nm and 29 nm, respectively. The Raman spectra reveal five sharp peaks at 253 cm-1, 307 cm-1, 359 cm-1, 485 cm-1, and 628 cm-1 for β-NaYF4:Yb3+/Er3+, whereas α-NaYF4:Yb3+/Er3+ shows two broad peaks centred at 272 cm-1 and 721 cm-1. The optical property measurements show that α- and β-NaYF4:Yb3+/Er3+ phases have distinct upconversion emission and temperature sensing behavior. The upconversion emission measurements show that β-NaYF4:Yb3+/Er3+ has higher overall emission intensities and green/red emission intensity ratio. The temperature-dependent upconversion emission measurements show that α-NaYF4:Yb3+/Er3+ has higher energy separation between 2H11/2 and 4S3/2 energy states. The temperature sensing performed utilizing these thermally coupled energy levels shows a maximum sensitivity of 0.0069 K-1 at 543 K and 0.016 K-1 at 422 K for β-NaYF4:Yb3+/Er3+ and α-NaYF4:Yb3+/Er3+, respectively.

Optical temperature-sensing phosphors with high sensitivities in a wide temperature range based on different strategies.

Rare earth ion doped luminescent materials are considered potential candidates with a wide range of applications because of their unique optical characteristics. In this work, single-phase Yb3+-Er3+ and Yb3+-Tm3+ co-doped La1.55SiO4.33 (LS) phosphors of a hexagonal system for optical thermometers are reported. Three characteristic emissions of Er3+ were observed at 521, 553 and 659 nm in the LS:Yb3+,Er3+ phosphors under 980 nm excitation, which are assigned to the 2H11/2 → 4I15/2, 4S3/2 → 4I15/2 and 4F9/2 → 4I15/2 transitions, respectively. In the LS:Yb3+,Tm3+ phosphors, one can find two strong emissions at 474 and 790 nm and two weak emissions at 648 and 685 nm. Their upconversion (UC) luminescence mechanisms were studied from their pump-power-dependent spectra. When the samples were measured at various temperatures, their spectral features revealed that different fluorescence intensity ratio (FIR) strategies can be used to characterize their optical temperature-sensing behaviors. The sensor sensitivities were determined from the temperature-dependent UC emission spectra using thermally coupled energy levels (TCELs) and non-TCELs, which had improved compared with those of some other reported optical temperature-sensing luminescent materials. The device fabrication indicated that the developed UC phosphors are promising for applications in optical thermometers.

White up-conversion La2Mo2O9:Yb3+, Ho3+, Tm3+ phosphors based on dual luminescence centers for high-sensitive optical thermometry

In this paper, the La2Mo2O9:Yb3+, Ho3+, Tm3+ phosphors are successfully synthesized through simple solid-state method. The white up-conversion luminescence is realized by appropriately varying the co-doped concentrations of Ho3+, Tm3+. The up-conversion luminescence characteristics and energy transfer processes of La2Mo2O9:Yb3+, Ho3+, Tm3+ are specifically analyzed upon 980 nm laser excitation. A strategy to enhance the optical temperature sensing performance is demonstrated via flexibly selecting diverse non-thermally coupled energy levels of dual luminescence centers with the fluorescence intensity ratio technology. The maximum values of absolute and relative sensitivity for the thermometer reach 0.2478 K−1 and 1.38% K−1 based on the non-thermally coupled energy levels of 3F2,3 (Tm3+)/5S2,5F4 (Ho3+). The luminescence color of La2Mo2O9:Yb3+, Ho3+, Tm3+ phosphors can maintain in the white region over the whole measured temperature range. These results indicate that the phosphors possess great potential in broad application prospects in the aspects of anti-counterfeiting, displays and non-contact temperature sensing.

Ultra-sensitive low-temperature thermometer regulated by the crystal field strength

Developing novel optical thermometry with ultrahigh relative sensitivity and temperature resolution has become a cutting-edge topic. For this purpose, under obeying Boltzmann distribution, a series of Li2Zn0.9992-xAxGe3-yByO8:0.08% Cr3+ (B= Sc3+, In3+, A = Si4+) phosphors were studied, which the luminescence intensity ratio between the transition of 4T2g→4A2g emission and the R line based on thermally coupled energy levels constitutes a temperature sensing work with a relative sensitivity of 9.46% K−1, 9.73% K−1, and 10.38% K−1, respectively. It is worth mentioning that the luminescence intensity of the R line (peak 1) increases significantly with the increase of temperature, while the transition of 4T2g→4A2g (peak 2) with high intensity at low temperature gradually quenching, and this opposite trend is an important advantage for the design of excellent thermometers. Compared the best relative sensitivity of Li2Zn0.9992-xAxGe3-yByO8:0.08%Cr3+ (B= Sc3+, In3+, A = Si4+) with the crystal field Dq/B, it can be concluded that relative sensitivity increasing gradually with decreasing the intensity of crystal field. Finally, by testing the stability of the sample at 50 K, a thermal resolution of 0.082 K, 0.080 K and 0.077 K was obtained, respectively, which is one of the best thermal resolutions so far, while the repeatability of the sample stability at 50 K and 300 K cycles was higher than 99%. Our work is expected to provide guiding insights for optimizing the sensitivity of Cr3+-based luminescence intensity ratio thermometers.

Germanate-based oxyfluoride transparent glass-ceramic embedded with Tm3+:Ca2YbF7 nanocrystals for high-performance optical thermometer

Germanate-based oxyfluoride transparent glass-ceramic functionalized by Tm3+:Ca2YbF7 nanocrystals was newly developed. The tremendously enhanced upconversion emission of 3F2,3 energy levels by in situ crystallization was extremely beneficial for constructing optical thermometry involving the indirect thermally coupled energy levels (1G4 and 3F2,3) of Tm3+ ions. Utilizing the fluorescence intensity ratio technique, the thermometry potentials of PG and GC8 were systematically evaluated based on the emissions from 3F2,3 and 1G4 energy levels. The relative and absolute sensitivities, thermometry resolutions, and repeatabilities were superior to many reported materials. This work provides an avenue for precipitating ternary fluoride nanocrystals containing rare earths in germanate-based oxyfluoride glass, and proposes a promising way to achieve high performance optical thermometry based on the emissions from widely spaced energy levels.

Enhanced upconversion emission in Er3+/Yb3+-codoped Al2Mo3O12 microparticles via doping strategy: Towards multimode visual optical thermometer

To explore highly sensitive luminescent materials, a series of Er3+/Yb3+-codoped Al2Mo3O12 microparticles were prepared through a high-temperature solid-state reaction method. The phase structure, light harvest ability, morphology, and upconversion (UC) emission characteristics of these synthesized microparticles were investigated systematically. Excited at 980 nm, glaring visible UC emissions are gained in the developed specimens, in which the optimal doping content for Yb3+ is 7 mol% and the two-photon absorption process contributes to the UC emission mechanism. Based on the fluorescence intensity ratio technology, the thermometric properties of resultant microparticles are studied by analyzing the temperature-dependent green UC emissions of Er3+ arising from the thermal coupling energy levels. The maximum absolute and relative sensitivities of final products are 0.011 K-1 and 1.09% K−1, respectively, and they are barely influenced by Yb3+ contents. Besides, via exploring the lifetimes of 2H11/2 and 4S3/2 levels of Er3+ at various temperatures, the relative sensitivities of resultant microparticles are determined to be 0.27% and 0.26% K−1, respectively. Furthermore, the newly developed microparticles can be adopted to fabricate fluorescent ink to realize optical anti-counterfeiting and visual temperature monitoring. Our studies demonstrate that Er3+/Yb3+-codoped Al2Mo3O12 microparticles with strong UC emissions possess great potential for multimode visual optical thermometry applications.

A Compact Fluorescent Probe for Real-Time Thermal Monitoring of Chips

In this paper, a compact fluorescent probe based on fluorescence intensity ratio (FIR) technique is proposed for real-time thermal monitoring of chips, the sensing unit of which is based on a self-made tellurite optical fiber (TOF) co-doped with Er <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3+</sup> /Yb <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3+</sup> ions. Temperature information was demodulated by analyzing the up-conversion fluorescence emission spectra generated using a 980 nm laser pump. Experimentally characterized the relationship between the FIR related to two thermally coupled energy levels and the ambient temperature, and on-line investigated the temperature change of Central Processing Unit (CPU) and North Bridge Chip for about 80 min during the cycle startup/shutdown process. The proposed probe exhibits a fast time response of about 1.1 s in a step temperature-varying environment and a small absolute error of <0.85 K in the real-time thermal monitoring of the CPU. To the best of our knowledge, this is the first report on fluorescent probes for thermal detection of chips. The proposed probe has the characteristics of anti-electromagnetic interference, explosion-proof, corrosion resistance, and can effectively avoid cross-sensitivity problems caused by environmental parameters. It provides a novel and reliable method for real-time thermal monitoring of chips.

The excellent dual optical thermometry of the Yb3+, Er3+ doped SrLu2O4

SrLu2O4: Yb3+, Er3+ samples were achieved successfully via a traditional solid-state method at 1450 °C. As 980-nm laser exciting, the UC spectra include red and green emissions mainly centering on 665 and 552 nm, respectively. The red is dominant, and the green part is a relative weakness. For all co-doped samples, intense red radiation is obtained. Meanwhile, the experimental formulas about pumping power and spectrum intensity helped us comprehend the up-conversion processes further, and the conclusion is a two-photon process in UC. The 4S3/2 and 2H11/2 levels ions are thermal coupled energy levels. We also investigated thermometric characteristics of the samples on the fluorescence intensity ration technology. For SrLu2O4: Er3+/Yb3+, it can be used as a temperature sensor by using its green emission and red emission, and the sensor sensitivity was calculated. The maximum absolute sensitivity and the relative sensitivity is 0.00226 K-1 and 0.0119 K−1 at 513 K for green emission and the maximum absolute sensitivity and the relative sensitivity is 0.00126 K-1 and 0.0026 K−1 at 303 K for red emission. The fluorescence intensity ratio (FIR) values are almost stable and accurate in repeated tests. As a result, the SrLu2O4: Er3+/Yb3+ samples would useful hopefully to optical engineering and sensors.

Intense red up-conversion luminescence and temperature sensing property of Yb3+/Er3+ co-doped BaGd2O4 phosphors

In this study, intense red and extremely weak green up-conversion (UC) luminescence was obtained in BaGd2O4: x mol% Yb3+/y mol% Er3+ phosphors under the excitations of 980 nm and 1550 nm. The corresponding maximum integrated intensity ratios of the red to green UC emissions are 50.3 and 158.7, respectively. The UC luminescence mechanisms upon different excitations were discussed. It was confirmed that two-photon and three-photon processes were responsible for both the red and green UC emissions excited at 980 nm and 1550 nm, respectively. The energy transfer efficiency from Er3+ to Yb3+ was calculated according to the fluorescence lifetime measurement under 1550 nm excitation. Temperature sensing based upon the thermally coupled energy levels 2H11/2/4S3/2 as well as thermally coupled Stark sublevels of 4F9/2 level of Er3+ was investigated under the excitation of 980 nm. The maximum absolute sensitivities were respectively obtained to be 0.42% K−1 at 573 K and 0.18% K−1 at 298 K. Our results indicated that BaGd2O4: Yb3+/Er3+ phosphors might be a kind of promising red UC phosphors with optical temperature measurement function.

Fluorescence temperature sensing of NaYF4:Yb3+/Tm3+@NaGdF4:Nd3+/Yb3+ nanoparticles at low and high temperatures

NaYF4:Yb3+/Tm3+@NaGdF4:Nd3+/Yb3+ upconversion nanoparticles were prepared using a solvothermal method, and the effects of key factors such as the content of sensitiser Nd3+ and Yb3+ on their luminescence properties were investigated. The nanoparticles are homogeneous in size and well dispersed. Under 808 nm excitation, it can produce strong upconversion fluorescence. At the same time, the nanoparticles have good temperature sensing properties at the thermally coupled energy levels of 700 and 646 nm for Tm3+. Using its fluorescence intensity ratio, accurate temperature measurements can be performed, and it has been found that it exhibits different temperature sensing properties in low and high-temperature regions. The maximum relative sensitivity was found to be 0.88% K−1 and 1.89% K−1 for the low-temperature region of 285–345 K and the high-temperature region of 345–495 K. The nanoparticles were applied to the internal temperature measurement of lithium batteries and the actual high-temperature environment, respectively, and were found to have good temperature measurement performance.

Developing Smart Temperature Sensing Window Based on Highly Transparent Rare-Earth Doped Yttrium Zirconate Ceramics.

Lanthanide-ion-based thermometers have been widely researched and utilized as contactless temperature sensing materials. Cooperating with the unique optical and excellent physical properties of transparent ceramics, Er3+/Yb3+ co-doped Y2Zr2O7 transparent ceramics were successfully fabricated as temperature sensing window materials. Homogeneous distribution of elements inside samples together with high transmittance (nearly 73%) makes it possible as an observing window. Upon excitation at 980 nm, room-temperature luminescent performance was systemically researched for explaining the energy transfer mechanism between Yb3+ and Er3+ ions. The FIR method was introduced for thermally coupled energy levels to realize temperature sensing ability. Detecting sensitivity at different temperatures was also calculated (1.24% K-1 at 303 K), suggesting that Yb3+, Er3+:Y2Zr2O7 are adequate for high sensitivity temperature detecting application. It is also investigated that the concentration of Yb3+ ions not only affects the emission color at room-temperature but also has influence on the sensitivity of temperature and 10 mol % Yb3+, 2 mol % Er3+:Y2Zr2O7 was found to be the most sensitive one. A demonstration experiment was also carried out to validate its application as a smart temperature sensing window. These results suggested that Yb3+, Er3+:Y2Zr2O7 transparent ceramics can have potential for temperature monitoring applications, especially as novel window materials under extreme circumstances.

Up-conversion luminescence transparent CaNb2O6 glass ceramics for temperature monitoring

To explore new up-conversion luminescent materials with high sensitivity for optical thermometry, Yb3+/Tm3+ co-doped transparent CaNb2O6 glass ceramics are successfully prepared using the traditional melting and controlling crystallization. Its structure, micro-morphology and luminescence characteristics are studied comprehensively by means of XRD, Raman, TEM and a fluorescence spectrometer. The results show that the luminescence intensity of glass ceramics is significantly higher than that of glasses under 980 nm laser excitation. A dual-mode temperature measurement based on fluorescence intensity ratios (FIR, I690/I796 and I690/I651) is realized by using the different temperature dependence of emission peaks of Tm3+. In a wide temperature range (298 − 573 K), the highest absolute sensitivity (Sa-max) of 0.42‰ K−1 and the supreme relative sensitivity (Sr-max) of 2.65% K−1 based on thermal coupling energy levels (TCELs) are gained. Furthermore, using non-thermal coupling energy levels (NTCELs), Sr-max and Sa-max reach 0.23% K−1 and 20.49% K−1, respectively. This work indicates that the CaNb2O6 glass ceramics as a new type of up-conversion luminescent material have great application prospects in the field of optical thermometry.

Temperature-responsive lanthanide-doped nanoarchitecture with orthogonal upconversion luminescence

Lanthanide-doped core-shell upconversion particles with tunable emission bands and intensities in response to external stimuli provide opportunities for multicolor barcoding, optical imaging, and temperature sensing applications. Here, we provide a universal template that can be used as a basic medium for color control and temperature sensing. In a representative nanostructure, i.e., NaYF4:Yb/[email protected]4:Yb/Tm, two excitation-emission spectra-orthogonal luminescence groups with naked-eye observable emission colors (cyan or yellow-green) were obtained by switching the excitation wavelength (980 and 1550 nm). Furthermore, the temperature-responsive optical performance of the nanostructure was investigated, and enhanced temperature sensitivities Sa (0.2339 K−1) and Sr (2.5286% K−1) were achieved based on 3F2,3/4S3/2 non-thermally coupled energy levels (NTCLs). The photophysical properties of the nanostructure show great potential for anticounterfeiting and non-contact temperature sensing applications.

Upconversion luminescence and optical temperature sensing of Er3+-doped La2Mo2O9 phosphors under 980 and 1550 nm excitation

A series of Er3+-doped La2Mo2O9 phosphors are prepared by the solid-state method. Up-conversion luminescence properties of La2Mo2O9:Er3+ are studied in detail under 980 and 1550 nm excitation. By inspecting the power dependent up-conversion intensity, indicating the two- and three-photon up-conversion population processes for 980 and 1550 nm excitation, respectively. The thermally coupled energy levels of 2H11/2 and 4S3/2 exhibit strong temperature dependence in the range of 293–533 K. Based on fluorescence intensity ratio technology, the La2Mo2O9:Er3+ phosphors present the maximum absolute sensitivity of 78.95 × 10−4 K−1 at 493 K and high relative sensitivity of 1.16% K−1 at 293 K under relatively safe wavelength of 1550 nm excitation. The results suggest that La2Mo2O9:Er3+ phosphor can be used as excellent optical temperature sensor.

High-sensitive temperature sensing based on thermal-enhanced emission and non-thermally coupled energy levels of white upconversion luminescence system

Na3Y(VO4)2:Nd3+,Yb3+,Ho3+,Tm3+ phosphors present significantly improved sensitivity of optical temperature sensing based on thermal-enhanced upconversion luminescence and non-thermally coupled energy levels. Under 808 nm excitation, white upconversion luminescence is successfully achieved in Nd3+-sensitized system. In addition, the emissions intensities originated from 4G5/2→4I9/2 transition of Nd3+ and 3F2,3→3H6 transition of Tm3+ gradually increase with elevating temperature owning to the thermal population effects, as opposed to the blue (1G4→3H6 transition of Tm3+), green (5S2,5F4→5I8 transition of Ho3+) and red (5F5→5I8 transition of Ho3+) emissions intensities show continuous decreasing trend. The temperature sensing behaviors are investigated by employing multiple non-thermally coupled energy levels. Based on non-thermally coupled energy levels of 4G5/2 (Nd3+)/1G4 (Tm3+), the absolute and relative sensitivities are obtained to be 0.433 K−1 and 2.81 % K−1. These results demonstrate that the Na3Y(VO4)2:Nd3+,Yb3+,Ho3+,Tm3+ phosphors with superior optical thermometry performance and white luminescence within a relatively wide temperature range can achieve optical applications in many fields.

Up-conversion luminescence and temperature sensing properties based on Y2GeO5: Er3+, Yb3+ phosphors for three-mode optical thermometry

Herein, a series of novel Y2GeO5: Er3+, Yb3+ phosphors were prepared through traditional high-temperature solid-state reactions under an air atmosphere. During whole experiments, the fluorescence intensity ratio (FIR), crystal structure, up-conversion (UC) luminescence, and energy transmission between Er3+ and Yb3+ of all the samples were combined to explore their properties as optical thermometer. By exciting 980 nm laser, strong UC luminescence of Er3+ ions was emitted at 522, 546, and 652 nm, and by increasing the Er3+, Yb3+ ions co-doped concentration, the UC luminescence intensity of Er3+ ions was greatly enhanced. By using two different techniques, a dual-mode temperature sensor was explored based on the FIR of thermal coupling (2H11/2/4S3/2) and non-thermal coupling (2H11/2/4F9/2) energy levels. And the maximal relative sensitivities of thermal coupling and non-thermal coupling were 1.17%·K−1 and 1.71%·K−1, respectively. In addition, the fluorescence lifetime was used as the third temperature detection signal. And the maximum of relative sensitivity based on fluorescence lifetime was 1.81%·K−1. All the above research shows that Y2GeO5: Er3+, Yb3+ phosphors are prospective applications in temperature sensing.

Up-conversion luminescence, temperature sensitive and energy storage performance of lead-free transparent Yb3+/Er3+ co-doped Ba2NaNb5O15 glass-ceramics

In this work, a new type of Yb 3+ /Er 3+ co-doped lead-free glass-ceramics (GCs) containing Ba 2 NaNb 5 O 15 nanocrystals was synthesized via traditional melt-quenching and controlled crystallization. The research results illustrate that a transparency of GCs can reach 50% at wavelength of 600 nm and the up-conversion (UC) luminous performance of GCs has been improved obviously compared with precursor glass (PG). And the dual-mode temperature measurement was carried out by fluorescence intensity ratio technology. Using thermally/non-thermally coupled energy levels (TCELs/non-TCELs), the maximum absolute sensitivities of S a-max (TCELs) and S a-max (non-TCELs) are 0.65% K −1 and 0.68% K −1 , and the maximal relative sensitivities of S r-max (TCELs) and S r-max (non-TCELs) are 1.19% K −1 and 0.90% K −1 , respectively. Furthermore, the discharge energy density (W d ) of 1.53 J cm −3 and the instantaneous discharge power density of 370 MW cm −3 with ultra-fast discharge time of 7 ns are simultaneously achieved in the GCs. These findings reveal the potential applications of new lead-free transparent Yb 3+ /Er 3+ co-doped Ba 2 NaNb 5 O 15 GCs for optical temperature measurement and energy storage. • Multi-function RE-doped Ba 2 NaNb 5 O 15 transparent glass ceramics were first fabricated. • Realizing dual-mode Up-conversion optical thermometry in the glass ceramics. • The maximum S r-max and S a-max can reach 1.19% K −1 and 0.68% K −1 . • Achieving high W d of 1.53 J cm − 3 and high P d of 370 MW cm − 3 at 600 kV/cm.