High-temperature Solid-phase Method Research Articles

Li4Ti5O12/C Composite Anode Material Synthesized Involving Absorbent Cotton for Li-Ion Battery

A puissant specific capacity spherical Li4Ti5O12 anode material of Lithium-Ion battery was successfully synthesized by two methods include a high-temperature solid-phase method using solid phase lithium and titanium sources, and a sol-gel method with liquid phase lithium and titanium sources. The carbon coating modification of Li4Ti5O12 anode material was carried out by adding absorbent cotton during the reaction process, and the effect of absorbent cotton addition on the structure, morphology and electrochemical performance of Li4Ti5O12 was studied. The composite prepared by sol-gel represents a superior first discharge specific capacity of 173 mAh·g−1 at 0.2 C rates, approximately 68 mAh·g−1 at 10 C rates, and the capacity of sample remained 103 mAh·g−1 after 100 cycles of 1 C rate charge/discharge process.

A robust strategy for crafting LiTiOPO4/CeO2 composites towards high rate lithium ion battery

LiTiOPO4/CeO2 composites as high-performance anodes for lithium-ion batteries (LIBs) were synthesized by a simple hydrothermal and high-temperature solid-phase method. X-ray diffraction (XRD) analysis results showed that CeO2-motified LiTiOPO4 was successfully prepared. Electron microscopy observation of the structural and morphological analysis data of the prepared materials further showed that CeO2 was coated on the surface of LiTiOPO4. X-ray photoelectron spectroscopy (XPS) showed different valence states of Ce4+/Ce3+ exist in LiTiOPO4/CeO2. The Ce3+-doped LiTiOPO4 with CeO2 surface modification was used to enhance lithium-ion storage performance by mediating voltage from 0.01 to 3.0 V. The rate capacity of the LiTiOPO4/CeO2 was maintained at 295.5 mAh g−1. The specific discharge capacity was maintained at 206.5 mAh g−1 after 1000 cycles, at 5 A g−1. The CeO2 not only significantly enhances ion diffusion and charge transfer, but also reduces polarization, promotes transport of Li+ to more storage sites in LiTiOPO4.

A multi-mode optical thermometer based on the up-conversion Ca3Y2Ge3O12: Er3+, Yb3+ phosphor

In order to develop a new up-conversion luminescent temperature measurement material with a garnet structure, Ca3Y2Ge3O12: Er3+, Yb3+ phosphors were prepared by a simple high temperature solid phase method. The structural phase and luminescence characteristics of the samples were characterized by X-ray powder diffraction, field emission scanning electron microscopy and photoluminescence spectra. It can be observed that the characteristic emission of Er3+ ion appears in the sample under 980 nm excitation, and it's up-conversion emission intensity increases with the increase of Yb3+ ion concentration. The maximum relative sensitivity is 1.29 %K−1, 1.09 %K−1 and 1.03 %K−1 based on the different temperature dependence of the thermal coupled energy levels (TCELs), non-thermal coupled energy levels (NTCELs) and the fluorescence lifetime (FL) of 4S3/2 state, respectively. The results show that Ca3Y2Ge3O12: Er3+, Yb3+ phosphor is excellent a material for optical temperature measurement.

Synergistic Strategy Using Doping and Polymeric Coating Enables High-Performance High-Nickel Layered Cathodes for Lithium-Ion Batteries

As one of the most promising cathode materials for lithium-ion batteries, nickel-rich layered oxide LiNi0.83Co0.11Mn0.06O2 (NCM83) has an inherent issue with rapid capacity decay caused by phase change and interface side reactions during the charge/discharge cycling. Herein, an effectively synergistic strategy for improving the structural stability and electrochemical performance of NCM83 cathodes has been proposed, combining surface polymeric coating with bulk doping by the high-temperature solid-phase method. The comprehensive results demonstrate that the niobium (Nb) element can be successfully bulk-doped into the crystal lattice, which could increase the layer spacing, thus stabilizing the crystal structure and minimizing the Li+/Ni2+ mixing in the as-prepared NCM83 cathode. Meanwhile, a small amount of Nb in the form of oxide and a layer of polyaniline (PANI) was coated on the NCM83 cathode’s surface. This not only can prevent electrolyte erosion and inhibit side reactions but also can effectively improve the transport coefficient of Li+ during the charge and discharge process. The optimized NCM83 cathode exhibited outstanding discharge-specific capacity (236.79 mAh g–1 at 0.2 C rate and 215.67 mAh g–1 at 2 C rate), stable cycling performance (capacity retention of 84.4% after 100 cycles at 2 C), and excellent rate performance (150.58 mAh g–1 at 10 C) by taking advantage of the synergistic effects. The synergistic strategy using Nb doping in combination with a surface polymeric coating can enhance the fundamental understanding of the high-nickel layered oxide cathodes for lithium-ion batteries.

Preparation and evaluation of H2TiO3@attapulgite with high adsorption and selectivity for lithium ions

In this work, the Li2TiO3@attapulgite (LTO@A-C-3) was prepared using attapulgite as a binder and a dispersant, based on the preparation of urea doped Li2TO3(LTO-C-3) by the modified high-temperature solid phase (m-HTSP) method. Urea addition changed the stacking fault concentrations and the attapulgite increased the lattice oxygen content, facilitating the production of isolated surface hydroxyl groups. HTO@A-C-3 exhibited a relatively high equilibrium Li+ adsorption capacity (Qe) of 48.44 mg·g−1. The selective adsorption capacity of HTO@A-C-3 was 46.27 mg·g−1, and the separation factors (αMLi) of Li+ exceeded 100 in Na+, K+, Mg2+ and Ca2+ coexisting salt solutions. The adsorption capacity was maintained at 39.12 mg·g−1, and titanium dissolution loss was less than 2.42% after five cycles.

Enhancement in electrochemical properties of boron-doped LiNi0.815Co0.15Al0.035O2 cathode

The lattice of the cathode material LiNi0.815Co0.15Al0.035O2 cathode (NCA) was doped with B3+ using a high-temperature solid-phase method, considerably improving the electrochemical properties of the NCA. Results of X-ray diffraction analysis and Rietveld refinement show that B3+ can enhance lattice ordering by minimising Li+/Ni2+ mixing. The scaning electron microscopy observations indicated that the B3+ doped changes the particle morphology. The specific discharge capacities of 1.5%B-NCA were 178.31 and 123.74 mAhg−1 at 0.2 and 5C, respectively. After 100 cycles, the specific discharge capacity was 176.29 mAhg−1 at 0.2C with a capacity retention of 98.87%. Boron doping significantly improves the structural stability of nickel-rich cathode materials by suppressing the detrimental H2→H3 phase transition, thus improving the electrochemical performance of nickel-rich ternary lithium-ion batteries.

Synthesis of Ni nanoparticles embedded porous Mo2C nanospheres for enhancing the electrochemical hydrogen storage properties of Co2B material

The porous Mo2C nanospheres were prepared by a high temperature calcination process. Different proportions of Ni nanoparticles were anchored and evenly distributed within the internal structure of porous Mo2C nanospheres via a hydrothermal process. Co2B hydrogen storage material was synthesized by a high temperature solid phase method. The Co2B + Mo2C and Co2B + Ni/Mo2C composites were manufactured via ball milling to improve the electrochemical hydrogen storage properties of Co2B. Eventually, the active materials doped Co2B composites electrodes revealed higher discharge capacities than conventional Co2B. More electrochemical active sites were provided for hydrogen adsorption and charger transfer owing to the extraordinary porous nanostructure and large specific surface area of Mo2C nanospheres. Moreover, the loaded Ni nanoparticles could further promote the electrical conductivity and electrocatalytic activity of Co2B. As a result, the Ni/Mo2C-1 modified Co2B electrode achieved a highest discharge capacity of 688.7 mAh/g. The two active species of porous Mo2C nanospheres and Ni nanoparticles played a synergistic role during the charging/discharging processes. In addition, the high-rate dischargeability (HRD), kinetic properties and corrosion resistance of Co2B were improved with the addition of Mo2C and Ni/Mo2C-1.

A novel reddish-orange-emitting phosphor Ca3Gd7(PO4)(SiO4)5O2: Sm3+ for white light-emitting diodes

Phosphor is the decisive material in white light-emitting diodes (WLED), affecting light quality. Silica phosphate has good stability, low cost and environmentally friendly features, so it has great application potential. In this paper, a self-activated reddish-orange phosphor Ca3Gd7(PO4)(SiO4)5O2: xSm3+ was prepared by the high-temperature solid-phase method. The phase purity of the sample was verified by X-ray diffraction (XRD). The Rietveld refinement method was used to resolve further the sample structure and the location of the substitution of rare earth ions. The photoluminescence properties were studied in detail using fluorescence spectra, temperature-dependent emission spectra and other characterization methods. The electron transition and energy transfer processes of Gd3+ in Ca3Gd7(PO4)(SiO4)5O2 were analyzed. The fluorescence decay curve of the sample was obtained, which belongs to the double exponential curve, and the decay lifetime depending on the Sm3+ doping concentration was calculated. Furthermore, a WLED device was assembled, and warm white light was obtained, with a spectrum showing characteristic red emission, proving to complement the missing red component of commercial WLEDs. These results indicate that Ca3Gd7(PO4)(SiO4)5O2: xSm3+ phosphor has great potential for application.

Potential application of Eu3+ ion-activated Ca2InTaO6 red phosphor with high thermal stability in WLEDs

The high-temperature solid-phase method synthesized a series of red phosphors Ca2InTaO6: xEu3+. Their most substantial emission peak is at 612 ​nm, FWHM ​= ​8 ​nm, and they can be excited under blue light. Has very excellent thermal stability, still has 77.7% of normal emission intensity at 150 ​°C, and the luminous intensity decreases very slowly between 80 ​°C–150 ​°C. In the high temperature durability test at 120 ​°C and 150 ​°C, the sample can still maintain good luminous intensity for a long time. The WLED was fabricated using fabricated samples in combination with commercial green and blue phosphors; it has Ra ​= ​90.1 and R9 ​= ​83.4. All expected test results prove that this sample is suitable for modern LED lighting.

Energy transfer and luminescent properties of Li2SnO3:Mn4+ phosphors

Li2SnO3:Mn4+ red phosphors were prepared using a high-temperature solid-phase method. The samples were characterized and analyzed by X-ray diffractometry, scanning electron microscopy, and fluorescence spectrometry, and the photoluminescence properties of the Mn4+-doped Li2SnO3 matrix were explored. The results show that the doping of Mn4+ did not change the crystal structure of the Li2SnO3 matrix but successfully substituted some Sn4+ sites into the substrate structure. The purity of the prepared samples was high, the distribution of the elements was uniform, and the particle size was at the micron level. Under ultraviolet light excitation of 330 nm, the highest emission peak of the Li2SnO3:Mn4+ phosphor was located at 658 nm in the red-light region, and the highest emission intensity was achieved when the Mn4+ dosage was 0.7%. The testing results of the light-emitting diode (LED) device that was packaged using Li2SnO3:Mn4+ phosphors as raw material showed that the Li2SnO3:Mn4+ phosphor was a suitable source of light for plant growth and can also be used to supplement the red-light component that white-light LEDs need.

Luminescent ionic lattice occupation and wide tunable emission spectra of La2MgZrO6:Bi3+,Eu3+ double perovskite phosphors for white light LED

La 2 Mg 1– x /2 Zr 1– x /2 O 6 : x Bi 3+ ( x = 0.01–0.035, abbreviated as LMZ:Bi 3+ ) and La 2– y Mg 0.99 Zr 0.99 O 6 :0.02Bi 3+ , y Eu 3+ ( y = 0.1–0.11, abbreviated as LMZ:Bi 3+ ,Eu 3+ ) double-perovskite phosphors were prepared through high-temperature solid-phase method. The emission spectrum of LMZ: x Bi 3+ ( x = 0.01–0.035) phosphors excited at 353 nm is asymmetric in the range between 375 and 650 nm, showing strong green light. There are two luminescent centers of [Mg1/Zr2–O 6 ] and [Mg2/Zr1–O 6 ] for Bi 3+ occupation, which were analyzed through different excitation wavelengths, Gaussian fitting peaks, fluorescence decay curves and Rietveld refinement of powder X-ray diffraction data. Through deep study of the luminescent lattices in the LMZ matrix, the green to blue tunning-emission is observed by different excitation wavelengths. In addition, red emission is obtained by co-doping Bi 3+ /Eu 3+ , and adjustable emission was investigated by changing the content of Eu 3+ in the co-doped phosphor formulation, so it is converted from green emission to red emission. The above results demonstrate how to tune emission color by co-doping rare earth ions in the double perovskite phosphor, which is attractive for future applications. The Gaussian deconvolution of the emission spectrum of LMZ:Bi phosphors was performed to obtain two sub-Gaussian components, and the selective site occupancy of Bi 3+ was analyzed. By co-doping Bi 3+ and Eu 3+ , the luminescence intensity of Eu 3+ can be effectively improved.

The effect of non-equimolar doping on the preparation and electrical conductivity of Sr(Ti,Zr,Zn,Sn,Hf)O3-σ high entropy perovskite oxide

A series of high entropy oxides (HEOSs) with non-isomolar ratios of perovskite structures were prepared by ball milling a mixture of SrO, TiO2, ZrO2, ZnO, SnO2 and HfO2 followed by sintering using a high-temperature solid-phase method. Both XRD and TG-DSC results indicate that single-phase Sr(Ti0.2Zr0.2Zn0.2Sn0.2Hf0.2)O3-σ is formed at 1500 °C. According to the SEM-EDS pictures, the elements in the oxide are uniformly distributed with no significant segregation or accumulation. The TEM results show that the polycrystalline ceramic powders can be classified as orthogonal Pbnm perovskite structure. The electrical conductivity (σ) was measured by the EIS technique and the activation energy (Ea) of HEOSs is calculated. In the temperature range of 300–750 °C, Sr(Ti0.28Zr0.18Zn0.18 Sn0.18 Hf0.18)O3-σ exhibits the highest conductivity (2.41 × 10−3 S/cm) and the lowest activation energy (Ea = 0.57 eV) due to lattice distortion and oxygen vacancy concentration.

Ultra-stable perovskite quantum dot composites encapsulated with mesoporous SiO2 and PbBr(OH) for white light-emitting diodes.

Lead halide perovskite quantum dots (QDs) with high fluorescence efficiency and high color purity have a broad application prospect in the field of backlight display, but poor stability has been a key factor limiting their commercialization. Herein, we successfully synthesized CsPbBr3 QDs-KIT-6 (CsPbBr3 -K6) composite by using KIT-6 molecular sieve as the limited template with a simple high temperature solid-phase method. Further, the semi-protected CsPbBr3 QDs in KIT-6 frame will spontaneously hydrolyze when encountering water, and finally the double-encapsulated CsPbBr3 QDs-KIT-6@PbBr(OH) (CsPbBr3 -K6@PbBr(OH)) composite are obtained. CsPbBr3 -K6@PbBr(OH) composite shows excellent green emission properties, including a photoluminescence quantum yield (PLQY) (~73%) and a narrow emission linewidth of 25 nm. It is interesting that, the composite has excellent stability, including water stability without attenuation of fluorescence intensity after soaking in water for 60 days, thermal stability of 120°C heating-cooling cycle, and excellent optical stability without attenuation under continuous ultraviolet irradiation.

Study on the preparation and luminescence properties of SrGe4 O9 :Mn4+ red phosphors for plant illumination.

In this study, SrGe4 O9 :Mn4+ red phosphors for plant illumination were prepared using a high-temperature solid-phase method. The samples were characterized and analyzed by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), fluorescence spectroscopy, and other techniques. The phase structure, apparent morphology, and luminescence properties of the SrGe4 O9 :Mn4+ red phosphors were investigated. The results indicated that the dopant Mn4+ was incorporated into the matrix structure by substituting some Ge4+ ions without any changes in the crystal structure of the SrGe4 O9 matrix. The samples comprised micron-scale particles and exhibited high purity and uniform distribution of elements. The SrGe4 O9 :Mn4+ phosphors exhibited relatively strong red light emission at 660 nm under the excitation of a 430-nm blue light, and the luminescence intensity was the highest when the Mn4+ doping amount was 1%. Proper doping of Ti4+ or Sn4+ could effectively improve the luminescence intensity of the SrGe4 O9 :Mn4+ phosphors. The light-emitting diode (LED) device packaging showed that the SrGe4 O9 :Mn4+ red phosphors could be used for plant growth illumination.

Enhanced triboelectric degradation of organics by tuning the synergy between ferroelectric polarization and illumination

It is urgently necessary to develop efficient and environmentally friendly catalysts to solve pollution problems faced by humankind. In this work, ferroelectric Ba2-xSr3+xLaNb7Ti3O30 (x = 0, 0.2, 0.4, 0.6) (BSLNT) tungsten bronze ceramics were prepared using a high-temperature solid-phase method and applied as tribocatalysts for degradation of organics. The built-in electric field in ferroelectric BSLNT was enhanced by modulating the ferroelectric polarization and by electrical poling. The degradation results show that better ferroelectric properties of the tribocatalysts led to better the catalytic capability with 92% RhB degradation after 2 h. The further enhanced polarization of the catalyst by electrical poling can improve the degradation efficiency of RhB to 96.8% in 2 h. Under the synergistic effect of illumination and friction, the degradation efficiency of RhB after 30 min reached 95.2%. Therefore, a highly efficient ferroelectric tribocatalyst with an enhanced built-in electric field for degradation of dye wastewater was demonstrated, expanding the application of ferroelectric materials in the catalysis field.

High Quantum Efficiency Rare-Earth-Doped Gd2O2S:Tb, F Scintillators for Cold Neutron Imaging.

High-resolution neutron radiography provides novel and stirring opportunities to investigate the structures of light elements encased by heavy elements. For this study, a series of Gd2O2S:Tb, F particles were prepared using a high-temperature solid phase method and then used as a scintillation screen. Upon reaching 293 nm excitation, a bright green emission originated from the Tb3+ luminescence center. The level of F doping affected the fluorescence intensity. When the F doping level was 8 mol%, the fluorescence intensity was at its highest. The absolute quantum yield of the synthesized particles reached as high as 77.21%. Gd2O2S:Tb, F particles were applied to the scintillation screen, showing a resolution on the neutron radiograph as high as 12 μm. These results suggest that the highly efficient Gd2O2S:Tb, F particles are promising scintillators for the purposes of cold neutron radiography.

Ca2YNbO6: Dy3+, Sm3+/Eu3+ warm white phosphors with tunable light color and FIR optical temperature measurement characteristics

The warm white phosphor samples Ca2YNbO6 (CYN): x mol Dy3+, y mol Sm3+/z mol Eu3+ were synthesized by the high-temperature solid-phase method. They have low CCT values and high thermal stability and still have more than 80% luminescence intensity at room temperature of 425 K, indicating that they can be used for WLED. The samples' emission (PLE) and excitation (PL) spectra were measured, and the reasons for the concentration quenching of CYN: x mol Dy3+, y mol Sm3+/z mol Eu3+ were analyzed. Meanwhile, it was found that the CYN: 0.05 mol Dy3+, 0.2 mol Eu3+ samples showed different trends in the two emission peaks of I575 and I612 under temperature variations. On this basis, an FIR temperature measurement model was developed with a maximum value of 3.14% k−1 for Sr, indicating that the sample has good optical temperature measurement characteristics.

Interaction of superionic conductor and heterostructure LiVOPO4-Li2.72Ti2(PO4)3 cathode materials for lithium-ion batteries

The heterostructure LiVOPO4-Li2.72Ti2(PO4)3 (LVOP-LTP) was synthesized using a hydrothermal process combined with a high-temperature solid-phase method. The electron microscopic analysis demonstrates that the sample has a heterojunction. The electrochemical performance tests reveal that the heterostructure LVOP-LTP has initial discharge-specific capacity of 88.4 mAh/g at 100 mA g−1, which is superior to the single-phase LiVOPO4 (LVOP, 25.1 mAh/g) and Li2.72Ti2(PO4)3 (LTP, 37.1 mAh/g). The improved electrochemical performance of heterostructure LVOP-LTP can be ascribed to the introduction of lithium superionic conductor (LISICON) and the formation of a heterojunction, which increases the lithium-ion pervasion channels and accelerates the lithium-ion transmission speed.

Al, Zr dual-doped cobalt-free nickel-rich cathode materials for lithium-ion batteries

Nickel-rich and cobalt-free cathode materials have obvious advantages in the aspects of energy density and economic efficiency. However, these materials are restricted from being used in commercial lithium-ion batteries due to the problems of poor structural stability and rate capability. In this study, the aluminum and zirconium dual-doped Co-free Ni-rich LiNi0.96Mn0.04O2 cathode material (NMAZ) is prepared by a facile high-temperature solid-phase method. The obtained NMAZ shows low cation disordering degree owing to the stability of transition metal slabs induced by strong Al–O and Zr–O bonds. Besides, the kinetics of lithium-ion diffusion is significantly improved by larger c-axis and the fast lithium-ion conducting Li2ZrO3 layer on the interface. As a result, NMAZ shows an improved capacity retention of 70.3% at 1C after 100 cycles under an elevated temperature (45 ​°C), compared with 50.5% of pure LiNi0.96Mn0.04O2. In addition, it exhibits splendid rate performance even at higher C-rate and better thermal stability compared to bare LiNi0.96Mn0.04O2. Hence, the Al, Zr dual-doped modification is beneficial to improving the structural stability and electrochemical performance of the Ni-rich and Co-free layered oxide cathodes for Li-ion batteries.

Dual-mode up/down-conversion optical thermometry of Pr<sup>3+</sup>-regulated Li<sub>0.9</sub>K<sub>0.1</sub>NbO<sub>3</sub>:Er<sup>3+</sup> phosphors

Photothermal sensing is crucial in developing smart wearable devices. However, designing and synthesizing luminescent materials with suitable multi-wavelength emission and constructing multiple sets of probes in a single material system is a huge challenge for constructing sensitive temperature sensors with a wide temperature range. In this paper, Pr<sup>3+</sup>, Er<sup>3+</sup> single-doped and double-doped Li<sub>0.9</sub>K<sub>0.1</sub>NbO<sub>3</sub> phosphors are successfully prepared by high temperature solid phase method, and their structures, morphologies, excitation wavelengths and temperature-dependent fluorescence properties are characterized by XRD, SEM, fluorescence spectrometer and self-made heating device. Firstly, the photoluminescences of the synthesized series of samples are investigated. The results show that comparing with the single-doped Li<sub>0.9</sub>K<sub>0.1</sub>NbO<sub>3</sub>: Er<sup>3+</sup> sample, the up/down-conversion spectra of Pr<sup>3+</sup>, Er<sup>3+</sup> co-doped phosphors under 808 nm/380 nm excitation show that the green fluorescence emission of Er<sup>3+</sup> is enhanced. In addition, under 980 nm excitation, Pr<sup>3+</sup> can effectively regulate the fluorescence energy level population pathway, so that the electrons are more effectively arranged in the <sup>2</sup>H<sub>11/2</sub> and <sup>4</sup>S<sub>3/2</sub> energy levels in the excitation process. The red emission is weakened and the green emission is enhanced, which improves the signal resolution of the fluorescent material and has a significant influence on the optical temperature measurement. Secondly, the up-conversion fluorescence property of Er<sup>3+</sup> under 808 nm/980 nm laser excitation in Li<sub>0.9</sub>K<sub>0.1</sub>NbO<sub>3</sub>:Er<sup>3+</sup> and Li<sub>0.9</sub>K<sub>0.1</sub>NbO<sub>3</sub>:Pr<sup>3+</sup>,Er<sup>3+</sup> phosphors are investigated. The results show that the red and green fluorescence emissions of Er<sup>3+</sup> are two-photon processes. Finally, the up/down-conversion dual-mode temperature sensing properties of Er<sup>3+</sup> in Li<sub>0.9</sub>K<sub>0.1</sub>NbO<sub>3</sub>:Er<sup>3+</sup> and Li<sub>0.9</sub>K<sub>0.1</sub>NbO<sub>3</sub>:Pr<sup>3+</sup>, Er<sup>3+</sup> phosphors are investigated. It is found that both materials have good optical temperature measurement performances. The Pr<sup>3+</sup> doping optimizes the dual-mode optical temperature measurement performances of Li<sub>0.9</sub>K<sub>0.1</sub>NbO<sub>3</sub>:Er<sup>3+</sup> phosphors derived from the thermal coupling energy level of Er<sup>3+</sup> ions. In addition, the up/down-conversion fluorescence mechanism of Li<sub>0.9</sub>K<sub>0.1</sub>NbO<sub>3</sub>:Er<sup>3+</sup> and Li<sub>0.9</sub>K<sub>0.1</sub>NbO<sub>3</sub>:Er<sup>3+</sup>, Pr<sup>3+</sup> phosphors are proposed, and the enhanced green fluorescence by Pr<sup>3+</sup> co-doping is attributed to the energy transfer from Pr<sup>3+</sup> ions to Er<sup>3+</sup> ions, leading to the increase of green fluorescence level population and the decrease of red fluorescence level population of the Er<sup>3+</sup> ions. This new dual-mode optical temperature measurement material provides a material basis and optical temperature measurement technology for exploring other temperature measurement materials.