MOF-based electrolytes exhibit excellent chemical and thermal stability, which can improve the service life and safety of the whole battery. The research of MOF electrolytes is expected to promote the progress and development of solid-state battery technology with high energy density and high safety.

The MOF electrolytes has more grain boundaries, which tend to cause interfacial problems such as dendrite growth. In order to eliminate the grain boundaries of MOF, vitrification is a more effective strategy. However, the strong coordination bonds between the metal and organic ligands in MOF lead to high melting points and higher energy consumption required for the MOF glass preparation. In addition, the melting point and decomposition temperature of MOF are very close, and only several MOF can melt when heated, and most of MOF will decompose before melting, accompanied by carbonization of organic ligands, and oxidation of metal ions.

Therefore, for most MOF crystals, it is challenging to transform them into glass state by the conventional melt-quenching method. To expand the variety of MOF glasses, researchers have increased the entropy of melting by introducing functional groups with electron-absorbing ability and modified MOFs by strategies such as ion exchange and surface engineering, thereby lowering the melting temperature of MOFs. However, there is no clear mechanistic guidance for the melting point regulation of MOF crystals, and the relationship between its coordination bonds and its melting process is still unclear.

By introducing different functional groups with different electron-withdrawing/donating effects on organic ligands, the strength of coordination bonds between metal ions and organic ligands can be adjusted, through which the mechanism and influence law of MOF melting point regulation is investigated. The ligand and metal ions were dissolved in 15 mL of DMF, and then the above solutions were heated and held at 130 ℃ for 48 h. After cooling, the products were collected by centrifugation, washed out with DMF (dimethylformamide) for three times, and finally dried under vacuum at 120 ℃ for 12 h. The obtained TIF-4 crystals were placed into a tube furnace and further held at 380 ℃ for 5 min under argon gas atmosphere, then cooled to room temperature to obtain TIF-4 glass (a_gTIF-4). A series of TIF-4 crystals using different halogen groups with same structure were prepared via solvothermal method at 130 ℃ in DMF. The strength of the coordination bonds was investigated via FTIR and DSC, from which the influence of the coordination bonds on the melting behavior of MOF were investigated systematically.

With the enhancement of the electronegativity of functional groups or the increase of the content of strong electronegative functional groups, i.e. the enhancement of the electron-withdrawing effect of functional groups, it can weaken the coordination bond between the ligand and the metal centre and lower the melting point of the MOF; on the contrary, through the introduction of electron-donating groups (methyl groups), it can enhance the coordination bond through the electron-donating effect and increase the melting point of the MOF. A series of TIF-4 crystals using different halogen groups and same structure were prepared, and the Tm of TIF-4 (from 375 ℃ to 295 ℃) gradually decreased with the enhancement of the electron-withdrawing ability of the halogen functional groups. The strength of the coordination bond was regulated by the electron-withdrawing/donating and the low-temperature preparation of MOF glass was realized. Meanwhile, it provides more theoretical guidance for the preparation of MOF glass, effectively avoids the decomposition of MOF in the melting process, improves the quality of MOF glass, reduces the preparation cost of MOF glass, and provides the theoretical basis and technical support for the application of MOF glass in the field of electrolytes and other fields, and also has a certain role in promoting the development and application of MOF.

The relationship between the electron-withdrawing/donating of functional groups on organic ligands and the strength of coordination bonds is clarified, and its influence on the melting point of MOF is revealed, which facilitate the preparation of MOF glass with low melting temperature and high thermal stability. This work shows that the electron-withdrawing/donating effect could be utilized to regulate the melting point of MOF, which provides an effective strategy for the preparation of more different types of MOF glasses. This work could promote the large-scale preparation of low-cost and high-quality MOF glasses and promote the practical application of MOF glasses in different fields.

The composition of the parent glass is 69SiO₂-24B₂O₃-7Na₂O. The prepared parent glass is heat treated at a temperature slightly higher than glass transition temperature for a certain time to produce nanoscale phase separation. The alkali-rich borate phase was dissolved by acid leaching, while the silicon-rich phase was retained, thus forming nanoscale pores. The size of pore size caused by acid leaching can be controlled by adjusting the temperature and time of heat treatment. By further alkali washing out, the silica material accumulated in the rigid pores of the silicon-rich phase skeleton can be removed, so as to expand the volumes of pores. CsPbBr₃ quantum dots are not synthesized in advance. CsBr and PbBr₂ are dissolved in water, and then add PG powder. Cs⁺, Pb²⁺, Br^- will be adsorbed in the PG glass channels. After drying the aqueous solution, CsPbBr₃ underwent in-situ crystallization in the pore channels to obtain the CPB-PG composite.

XRD analyses demonstrate the precipitation of CsPbBr₃ nanocrystals from glass matrix. The crystalline phase is dependent on the feeding amount of CsBr and PbBr₂. When the feeding amount gets higher than 0.12 mmol, the Cs₄PbBr₆ impurity phase will precipitate out. Careful TEM analyses were performed to reveal the microstructural features of the precipitated CsPbBr₃ nanocrystals. Interestingly, one can see some twin crystals, i.e., two crystals form a mirror-symmetric orientation relationship along a crystal plane. The formation of twins helps to stabilize the phase structure. The crystal size of CsPbBr₃ gradually increases in the following the sequence: CPB-PG1<CPB-PG2<CPB-PG3.

With the increase of crystal size, the luminescence peak redshifts: 514 nm→527 nm→532 nm, which is related to the quantum confinement effect. The half-peak full width (FWHM) of CPB-PG2 sample is the narrowest, merely 18 nm. The luminescent dynamical studies reveal that the luminescent decay curves can be well fitted by the double exponential function of equation, where the fast (τ₁) and slow (τ₂) lifetime components can be determined. τ₁ gets close to the lifetime of colloidal CsPbBr₃ quantum dots reported in the literature (5-10 ns), and can be attributed to the exciton recombination fluorescence transition process affected by non-radiative relaxation process. τ₂ results in the delay of fluorescence decay, which can be attributed to the trapping effect of shallow trap level. It was found that with the increase of crystal size, τ₁ tends to decrease, indicating that the number of defects leading to fluorescence non-radiative relaxation may increase; meanwhile, τ₂ increases, indicating that the associated shallow trap level defects also increase. It can be inferred that when CsPbBr₃ melted and recrystallized in PG glass with large pore size, the quantum dot components may be more easily volatilized through pores, resulting in more vacancy defects.

Benefiting the narrow FWHM of CPB-PG2, the CIE coordinate of (0.142, 0.782) gets close to the green coordinates defined by the standard Rec. 2020 standard (0.170, 0.797). Upon coupling the glass with blue LED chips, the electroluminescence is very bright. In order to verify the potential application of CPB-PG for w-LED , the CPB-PG2 powders, K_0.42Cs_0.58Pb(Br_1.5I_1.5) quantum dots glass powder and silica gel were mixed together, and then coated on the surface of InGaN 450 nm blue LED chip, whereupon w-LED prototype device was constructed. The constructed W-LED yields luminous flux of 1.58 lm, luminous efficiency of 30 lm/W, CCT of 7 710 K, CRI of 75.8, color coordinates of (0.284, 0.358), and covering 96% color gamut under the Rec. 2020.

Using porous glass as template, CPB-PG composites were prepared by impregnating porous glass powder in halide salt solution, CsPbBr₃ nanocrystals in-situ precipitate out in the pore channels during the succeeding heating and cooling processes. The crystal size of CsPbBr₃ can be adjusted by varying the pore size of porous glass under different heat treatment, acid leaching and alkali washing conditions. The prepared CPB-PG composite emits green light in a narrow band with a FWHM of 18 nm, corresponding to a quantum efficiency of 56%. Fluorescence kinetic analysis revealed that there are structural defects in CPB-PG, greatly affecting the fluorescence properties. The constructed w-LED prototype device can cover approximately 96% color gamut under the Rec. 2020 standard, demonstrating a potential application in LCD backlight displays.

Glassy metal-organic frameworks are emerging types of materials that could combine the modular tunability and high porosity of crystalline metal-organic frameworks (MOF) and the high processability of glassy materials. However, it remains difficult to obtain glassy MOF with high porosity. Thus, an alternative design strategy of embedding crystalline MOF nanocrystals into glassy MOF becomes very attractive to achieve materials with high porosity and liquid-like processability. Glassy materials based on titanium alkoxides are suitable host material for this purpose, which are easy to synthesis at large scale under mild conditions. Also, metal-organic polyhedral (MOP), as the molecular analogue for MOF, are also promising material for synthesizing composite materials. In this report, we developed a series of composite materials made of crystalline MOF and discrete MOP embedded in MOF glasses based on titanium-oxo cluster nodes and alkoxide linkers, and studied their porosity, crystallinity and morphology, which would pave the way for developing composite materials based on MOF glasses.

The prototype crystalline MOF, UiO-66, ZIF-8 and HKUST-1 were synthesized through solvothermal condition according to literature reports. The titanium alkoxide glass is made by mixing titanium precursor, titanium isopropoxide and the corresponding alcohol linker in alcohol solvents followed by evaporating the solvent at elevated temperature. To obtain the MOF@MOF glass composite materials, MOF nanocrystals were simply dissolved in the solution mixtures that were used to obtain titanium alkoxide glasses. The MOF@MOF glass composite materials were then washed out with various solvents and activated with super-critical CO₂ drying, and then tested for N₂ uptake at 77 K to obtain porosity data. The crystallinity of MOF after synthesis were measured by XRD, and the composite materials were studied by SEM. For the composite material using MOP, the hydroxyl functionalized MOP were synthesized in a method similar to literature, and then reacted with titanium precursor to produce the corresponding Ti-MOP material, following by investigation on its surface area.

The UiO-66 and HKUST-1 remain the crystallinity unvaried before and after synthesis. The composite material of UiO-66@Ti-PEG-BTM and HKUST-1@Ti-PEG-BTM show surface area of 375 m²/g and 368 m²/g, respectively. Conversely, ZIF-8 loses its crystallinity in the composite material, which has very low surface area. It is speculated that the ZIF-8 structure is unstable with the coordination competition of titanium alkoxide glass precursors. The Ti-MOP composite material also shows higher porosity than that of the MOP itself, showing that such synthetic strategy is promising to produce porous materials.

We developed a series of optically transparent glassy MOF made from titanium-oxo clusters linked with multi-dentate alcohol linkers, which could be modularly designed and synthesized under mild and environmentally friendly conditions. MOF nanocrystals were succeedingly embedded in the glass to prepare porous composite materials. For UiO-66 and HKUST-1, they retained high crystallinity and porosity in the MOF glasses, whereas ZIF-8 lost its crystallinity. We also developed composite materials based on metal-organic polyhedral and glassy MOF, which also showed high porosity. We therefore developed a new type of MOF glass that could be synthesized under mild condition and showed good compatibility with crystalline MOFs, from which a series of glass-crystal composite material with high porosity were successfully produced. We believe this research provide new opportunities for developing porous composite materials based on glassy MOF.

Coating PQDs in transparent glass media has greatly enhanced stability while maintaining excellent optical properties, so as to attract widespread attention from researchers in recent years. Utilizing femtosecond laser technology enables the manipulation of crystallization behavior of perovskite quantum dot glass in three-dimensional space, which holds significant implications for three-dimensional optical information encryption and storage. Additionally, the interaction between femtosecond laser and PQDs embedded glass enables reversible luminescence, laser emission, polarization, and long persistent luminescence properties, significantly expanding the application domains of PQDs embedded glass. However, many challenges still exist in the direction of femtosecond laser and PQDs embedded glass that researchers need to explore and resolve. The challenges are: how to use femtosecond laser to fabricate perovskite waveguides or single crystals in glass, potentially endowing inorganic glass with optoelectronic properties; how to design and to fabricate lead-free perovskite glass using femtosecond laser to further investigate its optical applications while maintaining non-toxic high optical performance; how to utilize femtosecond laser as pump sources to achieve laser output from PQDs embedded glass at room temperature; how to design specific optical devices and principles to further reduce the size of PQDs written inside glass to the nanometer scale using femtosecond laser, which is expected to greatly enhance the three-dimensional optical information storage capacity, etc. It is believed that in the near future, PQDs embedded glass under the influence of femtosecond lasers will lead us into a brand-new optoelectronic world.

In this paper, we delve into the preparation methods, crystallization, and emission mechanisms of cesium lead halide quantum dots glass. Emphasis is placed on the stability challenges encountered in practical applications, including temperature variations, light exposure, and humidity. Significant strides in addressing these challenges are highlighted, offering insights into potential avenues for future research endeavors.

At the same time, quantum dots glass retains the excellent optical performance of CsPbX₃ PQDs. Studies have shown that enhancing the rigidity of the glass network structure, such as replacing GeO₄ tetrahedra with SiO₄ tetrahedra, helps enhancing the water resistance of quantum dots glass. Additionally, using tellurite-based glasses with a higher density to encapsulate QDs or doping with high atomic number rare earth ions, such as Gd³⁺ and Lu³⁺, contributes to improve the material's radiation resistance. However, the understanding of the damage mechanism of PQDs glass under high energy beam irradiation, the thermal erasure mechanism, and the PL quenching mechanism of quantum dots glass at high temperatures is not deep enough at present. There is an urgent need for more direct experimental and theoretical research.

The development of quantum dots glass represents a significant leap forward in enhancing the long-term stability of CsPbX₃ QDs. With the in-depth study of the synthesis process of quantum dots glass, by designing rational glass compositions and regulating the precipitation process of CsPbX₃ PQDs, comprehensive optimization of optical performance can be achieved. By harnessing the unique properties of both QDs and glass matrices, this composite material not only overcomes stability limitations but also opens new frontiers in optoelectronics. It provides new perspectives for improving the current state of quantum dots glass and is expected to play a crucial role in various optical fields. Moving forward, continued research and innovation in this field hold immense potential for revolutionizing optoelectronic device design and functionality.

In recent years, all-inorganic halide perovskite (CsPbX₃, X=Cl, Br, I) quantum dots (QDs) have attracted widespread attention due to their excellent optical and electrical properties. They exhibit high photoluminescence (PL) efficiency, narrow emission bandwidth and tunable emission energy at a wide spectral range. However, the poor stability of CsPbX₃ QDs under ambient conditions strongly limit their applications. In this work, CsPbI₃ QD-doped borosilicate glasses were prepared by high-temperature melting-quenching followed by heat treatment. ZrO₂ is employed as the network modifier, which effectively modifies the local network structure of glass. By optimizing the concentration of ZrO₂ and the heat treatment temperature or time, the PL efficiency of the glass can be effectively improved. PL intensity of the QDs glass sample demonstrates high stability, which is almost unchanged after multiple heating and cooling cycles between 293 K and 373 K.

The CsPbI₃ QD-doped glasses were prepared by high-temperature melting-quenching followed by heat treatment. All raw materials with the designed ratios were accurately weighed and mixed in an agate mortar for 20 min. After the raw materials were thoroughly mixed, they were placed in a covered alumina crucible and transferred to a muffle furnace for melting at 1200 ℃ for 20 min. Afterwards, the glass melt was quenched onto a steel plate and pressed into a glass plate. Finally, the precursor glass were heat-treated at different temperatures (520-550 ℃) for 4 h and at 530 ℃ for different times (2-12 h) to precipitate the CsPbI₃ QDs.

PL spectra, PL decay curves and thermal stability of glass samples were examined with a FLS 980 fluorescence spectrometer. Optical absorption spectra were recorded by using a UV-3600UV-Vis-NIR spectrometer. X-ray diffraction patterns were recorded by using an X'Pert PRO powder diffractometer. The network structure of glass was analyzed by using a Nicolet 6700 spectrometer and an InVia Reflex Raman spectrometer. The photoluminescence quantum yield (PLQY) was measured with an absolute PLQY measurement system.

From the XRD results, as the heat treatment time increases, two diffraction peaks at angles (2θ) of 28.5° and 35.5° become stronger in intensity, corresponding to the (200) and (211) planes of CsPbI₃ QDs, respectively. With increasing the ZrO₂ concentration, the diffraction peak of (200) crystal plane shifts to a larger angle, which is attributed to the replacement of larger Pb²⁺ ions by smaller Zr⁴⁺. Based on FTIR and Raman spectra characterizations, the network structure of glass is mainly composed of [BO₄], [SiO₄] and [BO₃] units. As the ZrO₂ concentration increases, the fraction of tetrahedral network structure formed by [BO₄] and [SiO₄] units in the glass increases, leading to an increase in the fraction of the three-dimensional network structure of the glass, therefore inhibiting the crystallization of CsPbI₃ QDs and reducing the size of QDs. This results in the blue shift of the absorption edge and emission peak wavelength. From the emission spectra, with increasing the ZrO₂ concentration, the PL intensity of the glass samples first increases and then decreases. Both the absorption edge and emission peak wavelength show a clear redshift with increasing the heat treatment temperature or time, which is mainly attributed to the increased size of QDs. According to the PL decay curves, as the ZrO₂ concentration increases, the PL lifetime of glass gradually decreases; as the heat treatment temperature increases, the PL lifetime of glass gradually increases. Finally, after multiple heating and cooling cycles at 293-373 K, there was no significant decrease in the PL intensity of the glass.

The CsPbI₃ QD-doped borosilicate glass was prepared successfully by high-temperature melting-quenching followed by heat treatment. X-ray diffraction shows that CsPbI₃ QDs are precipitated in the glass. With increasing the ZrO₂ concentration, the PL intensity of the glass samples first increases and then decreases, and the highest PLQY reaches 32.6%. In addition, the emission peak wavelength and absorption edge show a blue shift, which is attributed to the increased fraction of tetrahedral network structures formed by [BO₄] and [SiO₄] units in the glass at higher ZrO₂ concentrations. Consequently, the increase in the fraction of the three-dimensional network structures of the glass impedes the movement of Cs⁺, Pb²⁺ and I^-, inhibiting the crystallization of CsPbI₃ QDs. After multiple heating and cooling cycles at 293-373 K, there was no significant decrease in the PL intensity of the glass, indicating that Zr⁴⁺ doped CsPbI₃ perovskite QDs glass has good thermal stability, which may find applications in display, lighting and other fields.

Silica aerogel is a novel nanostructured material, and the exceptional transparency makes it invaluable for applications in photothermal conversion, energy storage, building insulation, solar collector, and advanced optical devices. Silica aerogels could serve as the key component of devices in field of radiation detection due to their exceptionally high transmittance. Although numerous studies have addressed the transparency of silica aerogels, there is a notable gap in research for regarding the relationship between the transmittance and aerogel thickness. Consequently, it still remains a challenging problem for effectively maintaining high aerogel transmittance (approaching 80% at 550 nm) at a specific thickness (approaching 10 mm). In this work, the titration experiments were first concluded to identify optimal synthesis parameters, which was beneficial to investigate the phase demarcation points in the ternary phase diagram. Subsequently, according to the optimal parameters, highly transparent silica aerogels were prepared by using the sol-gel method. Additionally, a comprehensive examination of silica aerogels, including density, microstructure and transmittance, was conducted in detail.

The synthesis of silica aerogels was conducted through the sol-gel method. The following materials were employed: Tetraethoxysilane (TEOS, 98%) as the silica precursor, ethanol (EtOH) as the solvent, water (H₂O) as the hydrolysis reactant, and ammonium hydroxide solution (NH₄OH, 25%) as the catalyst, respectively. The alcogels were dried by ethanol supercritical drying to obtain transparent silica aerogels. The morphology and microstructure of silica aerogels were observed by a Zeiss EVO-50 XVP scanning electron microscope (SEM). The UV-Vis spectrophotometer was used to test the aerogel transmittance in the wavelength range of 500-800 nm. The specific surface area of aerogels was calculated by Bruno-Emmett-Teller (BET) method. Under the relative pressure p/p₀=0.99, the total pore volume was calculated by nitrogen adsorption-desorption isotherm. The related pore size distribution was obtained by Barret-Joyner-Halenda (BJH) method.

The solvent titration experiment data was normalized and subsequently used to construct the ternary phase diagram. The ternary phase diagram clearly demonstrated the phase transition boundary, single-phase region and multi-phase region, respectively for three solvents at room temperature. Thus, the ternary phase diagram could be employed to predict whether any mixture of three solvents results in a transparent solution, regardless of its proportions. The silica aerogels were prepared by using the parameters of ternary phase diagram. Specifically, it was seen that the higher initial transmittance the sols had, the similarly higher transmittance the aerogels also had. Moreover, the related transmittance of the sol-gel-aerogel system in the single-phase region demonstrated the highest value (~80.3%), which was better than that (~74%) on the phase transition boundary. The silica aerogel with the higher transmittance could be prepared in the single-phase region, and it provided a new idea for further study around the single-phase region of ternary phase diagram.

In order to manipulate the phase boundary point for accessing the single-phase transparent interval, the ethanol volume fraction in the mixture increased along the extension of the selected phase boundary point. It illustrated that the aerogel transmittance first rose with the increase of ethanol volume fraction. However, it decreased with the excessive ethanol. With an increase of ethanol volume fraction, the average particle size of silica aerogels decreased first and then increased. Moreover, the relationship between average particle size and transmittance were further established. The average particle size had a linear relationship with the transmittance of silica aerogels, meaning that the smaller the average particle size was, the larger the aerogel transmittance was. Furthermore, the skeleton particle boundary size of Rayleigh scattering and Mie scattering could be calculated and the corresponding particle boundary size at a wavelength of 550 nm was calculated to be 57 nm. The aerogel transmittance at a wavelength of 550 nm was further compared with the cumulative frequency of skeleton particles whose size were the smaller than the boundary one (~57 nm). It could be concluded that the aerogel transmittance had a certain linear correlation with the cumulative frequency. Obviously, the largest cumulative frequency (~94.68%) corresponded to the highest transmittance (the transmittance of sample C3 was 79.6%), while the lowest cumulative frequency (~83.05%) corresponded to the lowest transmittance (the transmittance of sample C5 was 69.5%).

According to the ternary phase diagram, the highly transparent silica aerogels were precisely prepared by using the optimal synthesis parameters. The higher initial transmittance of the sols induced a higher transmittance of the aerogels. Furthermore, the smaller the average particle size, the larger the transmittance of silica aerogels could be, which was attributed to the larger cumulative frequency of particle size smaller than 57 nm due to the suppression of Mie scattering opaque effect. Besides, the higher pore size meant the lower aerogel transmittance, which was caused by the stronger light scattering effect. In a word, the highly transparent silica aerogel with transmittance (~80.3% at 550 nm) at a specific thickness (~10 mm) was successfully fabricated by the sol-gel method in the single-phase region, which would be satisfied with practical application requirements in Cherenkov radiation detector.

The energy transfer between lanthanide ions (Ln³⁺) and transition metal ions (Cr³⁺) typically leads to luminescence attenuation, which hinders their application in temperature measurement. However, this issue can be effectively addressed by synthesizing polyphase glass-ceramics that separate the Ln³⁺ and Cr³⁺ into different nano-crystals.

In this study, we designed polyhedral glass-ceramics (40SiO₂-20Al₂O₃-15LiF-10Ga₂O₃-0.1TmF₃-0.1ErF₃-0.05Cr₂O₃-1YbF₃-0.5SnO) doped with Ln³⁺/Cr³⁺ (Ln³⁺=Er³⁺/Tm³⁺/Yb³⁺). The up-conversion spectra of Tm³⁺ and Er³⁺ in the temperature range of 313-573 K, as well as the temperature-dependent properties of the emission intensity ratio of ²E and ⁴T₂ and fluorescence lifetime decay of Cr³⁺ were systematically investigated. The results demonstrate that Ln³⁺/Cr³⁺-doped polyphase glass-ceramics exhibit excellent performance as a four-mode fluorescence temperature measurement material.

Ln³⁺/Cr³⁺-doped glass samples were prepared using melt quenching technology, where the raw materials were melted in a lifting furnace at 1 500 ℃ for 1 h. The sample was then poured onto a preheated copper plate to 300 ℃ and shaped by pressing it with another copper plate. Subsequently, the sample was annealed in a Muffle furnace at 450 ℃ for 6 h to obtain precursor glass (PG). Finally, the PG sample underwent heat treatment at 780 ℃ for 2 h to produce glass-ceramics (GC780).

X-ray diffraction apparatus was employed to measure the XRD spectra of these samples. FS-5 fluorescence spectrometer was used to measure various spectra including up-conversion and down-conversion spectra at room temperature, power-dependent up-conversion spectra, temperature-dependent up-conversion and down-conversion spectra, as well as temperature-dependent fluorescence lifetime decay curves. Transmission electron microscopy techniques such as selective electron diffraction and high-power transmission electron microscopy were utilized to examine GC780 samples.

The diffraction peaks observed in the XRD pattern of GC780 exhibit excellent agreement with the standard cards of γ-Ga₂O₃ and β-YF₃ respectively, indicating the successful synthesis of polyphase glass-ceramics containing γ-Ga₂O₃ and β-YF₃ grains. The excitation and emission spectra of Cr³⁺ as well as the up-conversion spectra of Er³⁺ and Tm³⁺ indicate no energy transfer between Cr³⁺ and Er³⁺ or Tm³⁺.

In the variable temperature up-conversion emission spectra of GC780 sample within a temperature range of 313 to 573 K, the emission peak intensity ratio (FIR) I₅₂₂/I₅₄₃ and I₆₉₄/I₄₇₄, which change with temperature, were selected for temperature detection. As the temperature increases from 313 K to 573 K, there is a decrease in relative sensitive (S_R) for I₅₂₂/I₅₄₃ with increasing temperature, reaching a maximum value of 1.03%·K^-1 at 313 K. On the other hand, S_R for I₆₉₄/I₄₇₄ initially increases and then decreases with rising temperature, peaking at a maximum value of 1.45%·K^-1 at 473 K. In the down-conversion temperature-changing spectra (303-543 K) of Cr³⁺ excited at 397 nm, the intensity of the luminescence peaks at 615 nm and 720 nm is used to detect the temperature dependence of FIR(I₆₁₅/I₇₂₀). When the temperature is from 303 K to 543 K, S_R gradually decreases with increasing temperature, and the maximum value of 1.74%·K^-1 appears at 303 K. The relative sensitivity is 0.51%·K^-1 at 496 K when Cr³⁺ down-conversion attenuation curve is used to measure temperature dependence.

Polyphase glass-ceramics doped with β-YF₃ and γ-Ga₂O₃ nano-crystals in Ln³⁺/Cr³⁺ (Ln³⁺=Er³⁺/Tm³⁺/Yb³⁺) have been successfully synthesized by melt quenching method in this work. The up-conversion spectra of GC780 were measured in the temperature range of 313-573 K. The maximum relative sensitivities were 1.03%·K^-1 and 1.45%·K^-1, respectively, by selecting I₅₂₂/I₅₄₃ and I₆₉₄/I₄₇₄ intensity ratios. The ²E→⁴A₂ and ⁴T₂→⁴A₂ emission₂ peaks of Cr³⁺ were used for temperature detection, and the maximum relative sensitivity was 1.74%·K^-1 at 303 K. In addition, the Cr³⁺ down-conversion attenuation curve is used to measure the temperature dependence, and the maximum relative sensitivity is 0.51%·K^-1 at 496 K. The Ln³⁺/Cr³⁺ (Ln³⁺=Er³⁺/Tm³⁺/Yb³⁺) co-doped β-YF₃ and γ-Ga₂O₃ nano-crystals polyphase glass-ceramic is thus indicated to be a highly promising competitive four-mode self-calibration temperature measurement material.