Alkali-free SiO_(2)-Al_(2)O_(3)-CaO-MgO with different SiO_(2)/Al_(2)O_(3)mass ratios was prepared by conventional melt quenching method.The glass network structure,thermodynamic properties and elastic modulus changes...Alkali-free SiO_(2)-Al_(2)O_(3)-CaO-MgO with different SiO_(2)/Al_(2)O_(3)mass ratios was prepared by conventional melt quenching method.The glass network structure,thermodynamic properties and elastic modulus changes with SiO_(2)and Al_(2)O_(3)ratios were investigated using various techniques.It is found that when SiO_(2)is replaced by Al_(2)O_(3),the Q^(4) to Q^(3) transition of silicon-oxygen network decreases while the aluminum-oxygen network increases,which result in the transformation of Si-O-Si bonds to Si-O-Al bonds and an increase in glass network connectivity even though the intermolecular bond strength decreases.The glass transition temperature(T_(g))increases continuously,while the thermal expansion coefficient increases and high-temperature viscosity first decreases and then increases.Meanwhile,the elastic modulus values increase from 93 to 102 GPa.This indicates that the elastic modulus is mainly affected by packing factor and dissociation energy,and elements with higher packing factors and dissociation energies supplant those with lower values,resulting in increased rigidity within the glass.展开更多
The effect of glass network modifier R2O （R=Li, Na, K） on upconversion luminescence in Er3＋/yb3＋ co-doped NaYF4 oxyfluoride glass-ceramics was investigated. NaYF4 nanocrystals with different sizes were studied und...The effect of glass network modifier R2O （R=Li, Na, K） on upconversion luminescence in Er3＋/yb3＋ co-doped NaYF4 oxyfluoride glass-ceramics was investigated. NaYF4 nanocrystals with different sizes were studied under glass network modifier alkali mental oxide. The nanocrystals size in NaYF4 of Li2O modified samples was 11 nm, whereas in the Na20 and K2O modified sample, the crystal size was 25 and 43 nm, respectively. It was found that red, yellow and green upconversions were observed in SAL, SAN, SAK glass ceramics. The reported results would deepen the understanding of size effects on the lanthanide upcon- version in nanocrystals.展开更多
In order to investigate the influence of different heavy metal ions on the formation of the oxyfluoride glasses and glass ceramics, samples with different Pb F2/Cd F2 ratios have been prepared by the melting quenching...In order to investigate the influence of different heavy metal ions on the formation of the oxyfluoride glasses and glass ceramics, samples with different Pb F2/Cd F2 ratios have been prepared by the melting quenching and thermal treatment method. The different effects of Pb2 tand Cd2ton the glass network structure are investigated by FTIR and Raman spectra. During the formation of glass network structure, Pb2 tprefers to break the Sie Oe Si bond and subsequently bond to F for charge compensation, and Cd2 tprefers to break the SieO eA l bond and is surrounded by O2. Pb2 tand F gather together and form the fluoride nanocrystals,while Cd2 tremains in oxide matrix after thermal treatment. Introduction of proper Cd F2 is important to adjust and control the glass network structure and crystallization process in the fabrication of the transparent glass ceramics.展开更多
Large-scale and long-time molecular-dynamics simulations are used to investigate the temperature dependences of elastic properties for amorphous SiO2. The elastic moduli increase in a temperature range up to 1600 K an...Large-scale and long-time molecular-dynamics simulations are used to investigate the temperature dependences of elastic properties for amorphous SiO2. The elastic moduli increase in a temperature range up to 1600 K and decrease thereafter. The anomalous behaviour in elasticity is explained by analysing the changes of atomic-scale structure with respect to increment of temperature. The mechanism originates predominantly from distortion of the SiO4 tetrahedra network in low-temperature ranges. At an elevated temperature range, thermal-induced Si-O bond stretching dominates the process and leads to normal temperature dependence of elastic properties.展开更多
The microstructure modifications of sodium silicate glass induced by 1.2-MeV electron irradiation are studied by x-ray photoelectron spectroscopy and Raman spectroscopy. Depth profile analyses are also performed on th...The microstructure modifications of sodium silicate glass induced by 1.2-MeV electron irradiation are studied by x-ray photoelectron spectroscopy and Raman spectroscopy. Depth profile analyses are also performed on the irradiated glass at 109 Gy. A sodium-depleted layer with a thickness of a few tens of nanometers and the corresponding increase of network polymerization on the top surface are observed after electron bombardment, while the polymerization in the subsurface region has a negligible variation with the irradiation dose. Moreover, the formation of molecular oxygen after electron irradiation is evidenced, which is mainly aggregated in the first two-micron-thick irradiated glass surface. These modifications are correlated to the network relaxation process as a consequence of the diffusion and desorption of sodium species during electron irradiation.展开更多
Currently,a full-spectrum illumination scheme based on violet-light excitation is proposed to achieve high-quality and healthy lighting.Unfortunately,the most important yellow phosphors are extremely scarce owing to t...Currently,a full-spectrum illumination scheme based on violet-light excitation is proposed to achieve high-quality and healthy lighting.Unfortunately,the most important yellow phosphors are extremely scarce owing to the low absorption efficiency of violet light and low photoluminescence quantum yield(PLQY).In this study,glass network engineering of the B_(2)O_(3)-BaO-Sc_(2)O_(3) system was developed to fabricate violet-light-excitable yellow-emitting Ba_(2)Sc_(2)B_(4)O_(11)(BSB):Ce^(3+)glass ceramic(GC)with a record PLQY of 95.0%and superior stability.The optimized[BO_(3)]/[BO_(4)]ratio modifies the glass network structure,creating favorable sites for heterogeneous nucleation during in situ glass crystallization.This promoted the formation of well-crystallized BSB nanocrystals(NCs)within the glass matrix,consequently improving the optical performance of the BSB:Ce^(3+)GC composite.This enables the construction of both light-emitting diode(LED)-and laser diode(LD)-driven full-spectrum light sources with high color rendering indices(CRIs)exceeding 93,ensuring superior overall color reproduction quality.This exploration of violet-light-excitable GC composites is intended to accelerate the development of ideal sun-like lighting technology.展开更多
Femtosecond laser(fs)irradiation is an effective way to print perovskite quantum dots(PeQDs)in robust glass.Nevertheless,the laser writing-erasing-recovery process of PeQDs is highly dependent on the glass network str...Femtosecond laser(fs)irradiation is an effective way to print perovskite quantum dots(PeQDs)in robust glass.Nevertheless,the laser writing-erasing-recovery process of PeQDs is highly dependent on the glass network structure,which is far from being well understood.In this work,we demonstrate that the lanthanide oxides(Ln_(2)O_(3),Ln=La,Gd and Lu)in borosilicate glass enable to modulate the connectivity of the silicon-oxygen network and control in situ formation of CsPbBr_(3)PeQDs induced by fs laser.Importantly,PeQDs can be erased in specific regions through subsequent laser irradiation only when doped with an optimal concentration of Ln_(2)O_(3),which facilitates a looser network structure and reduces the crystallization barrier for ion migration.Subsequently,the degraded perovskite material can autonomously regenerate due to the water molecule invasion.The recovery time shows significant variation determined by the type and concentration of lanthanide ions.This reversible luminescence can be cycled multiple times while maintaining stable luminescence properties,providing a foundation for the development of innovative encryption methods in safeguarding information and anti-counterfeiting.展开更多
基金Supported by the National Key Research Program(No.2024-1129-954-112)National Natural Science Foundation of China(No.52372033)Guangxi Science and Technology Major Program(No.AA24263054)。
文摘Alkali-free SiO_(2)-Al_(2)O_(3)-CaO-MgO with different SiO_(2)/Al_(2)O_(3)mass ratios was prepared by conventional melt quenching method.The glass network structure,thermodynamic properties and elastic modulus changes with SiO_(2)and Al_(2)O_(3)ratios were investigated using various techniques.It is found that when SiO_(2)is replaced by Al_(2)O_(3),the Q^(4) to Q^(3) transition of silicon-oxygen network decreases while the aluminum-oxygen network increases,which result in the transformation of Si-O-Si bonds to Si-O-Al bonds and an increase in glass network connectivity even though the intermolecular bond strength decreases.The glass transition temperature(T_(g))increases continuously,while the thermal expansion coefficient increases and high-temperature viscosity first decreases and then increases.Meanwhile,the elastic modulus values increase from 93 to 102 GPa.This indicates that the elastic modulus is mainly affected by packing factor and dissociation energy,and elements with higher packing factors and dissociation energies supplant those with lower values,resulting in increased rigidity within the glass.
基金supported by the National Natural Science Foundation of China(61368007,61265004,51272097)the Specialized Research Fund for the Doctoral Program of Higher Education of China(20125314120018)
文摘The effect of glass network modifier R2O （R=Li, Na, K） on upconversion luminescence in Er3＋/yb3＋ co-doped NaYF4 oxyfluoride glass-ceramics was investigated. NaYF4 nanocrystals with different sizes were studied under glass network modifier alkali mental oxide. The nanocrystals size in NaYF4 of Li2O modified samples was 11 nm, whereas in the Na20 and K2O modified sample, the crystal size was 25 and 43 nm, respectively. It was found that red, yellow and green upconversions were observed in SAL, SAN, SAK glass ceramics. The reported results would deepen the understanding of size effects on the lanthanide upcon- version in nanocrystals.
基金supported by the National Science Fund for Talent Training in Basic Sciences (No. J1103208)
文摘In order to investigate the influence of different heavy metal ions on the formation of the oxyfluoride glasses and glass ceramics, samples with different Pb F2/Cd F2 ratios have been prepared by the melting quenching and thermal treatment method. The different effects of Pb2 tand Cd2ton the glass network structure are investigated by FTIR and Raman spectra. During the formation of glass network structure, Pb2 tprefers to break the Sie Oe Si bond and subsequently bond to F for charge compensation, and Cd2 tprefers to break the SieO eA l bond and is surrounded by O2. Pb2 tand F gather together and form the fluoride nanocrystals,while Cd2 tremains in oxide matrix after thermal treatment. Introduction of proper Cd F2 is important to adjust and control the glass network structure and crystallization process in the fabrication of the transparent glass ceramics.
基金Supported by the National Natural Science Foundation of China and the National Science Fund for Distinguished Young Scholars under Grant Nos 90403027 and 50772114.
文摘Large-scale and long-time molecular-dynamics simulations are used to investigate the temperature dependences of elastic properties for amorphous SiO2. The elastic moduli increase in a temperature range up to 1600 K and decrease thereafter. The anomalous behaviour in elasticity is explained by analysing the changes of atomic-scale structure with respect to increment of temperature. The mechanism originates predominantly from distortion of the SiO4 tetrahedra network in low-temperature ranges. At an elevated temperature range, thermal-induced Si-O bond stretching dominates the process and leads to normal temperature dependence of elastic properties.
文摘The microstructure modifications of sodium silicate glass induced by 1.2-MeV electron irradiation are studied by x-ray photoelectron spectroscopy and Raman spectroscopy. Depth profile analyses are also performed on the irradiated glass at 109 Gy. A sodium-depleted layer with a thickness of a few tens of nanometers and the corresponding increase of network polymerization on the top surface are observed after electron bombardment, while the polymerization in the subsurface region has a negligible variation with the irradiation dose. Moreover, the formation of molecular oxygen after electron irradiation is evidenced, which is mainly aggregated in the first two-micron-thick irradiated glass surface. These modifications are correlated to the network relaxation process as a consequence of the diffusion and desorption of sodium species during electron irradiation.
基金supported by the National Key R&D Program of China(No.2021YFB3500503)the National Natural Science Foundation of China(No.52272141,No.52572155)+1 种基金the Natural Science Foundation of Fujian Province(No.2024J02014)the Natural Science Foundation of Zhejiang Province(No.LY22E020008).
文摘Currently,a full-spectrum illumination scheme based on violet-light excitation is proposed to achieve high-quality and healthy lighting.Unfortunately,the most important yellow phosphors are extremely scarce owing to the low absorption efficiency of violet light and low photoluminescence quantum yield(PLQY).In this study,glass network engineering of the B_(2)O_(3)-BaO-Sc_(2)O_(3) system was developed to fabricate violet-light-excitable yellow-emitting Ba_(2)Sc_(2)B_(4)O_(11)(BSB):Ce^(3+)glass ceramic(GC)with a record PLQY of 95.0%and superior stability.The optimized[BO_(3)]/[BO_(4)]ratio modifies the glass network structure,creating favorable sites for heterogeneous nucleation during in situ glass crystallization.This promoted the formation of well-crystallized BSB nanocrystals(NCs)within the glass matrix,consequently improving the optical performance of the BSB:Ce^(3+)GC composite.This enables the construction of both light-emitting diode(LED)-and laser diode(LD)-driven full-spectrum light sources with high color rendering indices(CRIs)exceeding 93,ensuring superior overall color reproduction quality.This exploration of violet-light-excitable GC composites is intended to accelerate the development of ideal sun-like lighting technology.
基金supported by the National Natural Science Foundation of China(52272141,51972060)Natural Science Foundation of Fujian Province(2024J02014,2021J01190).
文摘Femtosecond laser(fs)irradiation is an effective way to print perovskite quantum dots(PeQDs)in robust glass.Nevertheless,the laser writing-erasing-recovery process of PeQDs is highly dependent on the glass network structure,which is far from being well understood.In this work,we demonstrate that the lanthanide oxides(Ln_(2)O_(3),Ln=La,Gd and Lu)in borosilicate glass enable to modulate the connectivity of the silicon-oxygen network and control in situ formation of CsPbBr_(3)PeQDs induced by fs laser.Importantly,PeQDs can be erased in specific regions through subsequent laser irradiation only when doped with an optimal concentration of Ln_(2)O_(3),which facilitates a looser network structure and reduces the crystallization barrier for ion migration.Subsequently,the degraded perovskite material can autonomously regenerate due to the water molecule invasion.The recovery time shows significant variation determined by the type and concentration of lanthanide ions.This reversible luminescence can be cycled multiple times while maintaining stable luminescence properties,providing a foundation for the development of innovative encryption methods in safeguarding information and anti-counterfeiting.
