A novel self-recoverable mechanoluminescent phosphor Ca_(5)Ga_(6)O_(14)∶Eu^(3+) was developed by the high-tem-perature solid-state reaction method,and its luminescence properties were investigated.Ca_(5)Ga_(6)O_(14)...A novel self-recoverable mechanoluminescent phosphor Ca_(5)Ga_(6)O_(14)∶Eu^(3+) was developed by the high-tem-perature solid-state reaction method,and its luminescence properties were investigated.Ca_(5)Ga_(6)O_(14)∶Eu^(3+)can produce red mechanoluminescence,and importantly,it shows good repeatability.The mechanoluminescence of Ca_(5)Ga_(6)O_(14)∶Eu^(3+) results from the piezoelectric field generated inside the material under stress,rather than the charge carriers stored in the traps,which can be confirmed by the multiple cycles of mechanoluminescence tests and heat treatment tests.The mechanoluminescence color can be turned from red to green by co-doping varied concentrations of Tb^(3+),which may be meaningful for encrypted letter writing.The encryption scheme for secure communication was devised by harnessing mechanoluminescence patterns in diverse shapes and ASCII codes,which shows good encryption performance.The results suggest that the mechanoluminescence phosphor Ca_(5)Ga_(6)O_(14)∶Eu^(3+),Tb^(3+)may be applied to the optical information encryption.展开更多
Graphene's large theoretical surface area and high conductivity make it an attractive anode material for potassium-ion batteries(PIBs).However,its practical application is hindered by small interlayer distance and...Graphene's large theoretical surface area and high conductivity make it an attractive anode material for potassium-ion batteries(PIBs).However,its practical application is hindered by small interlayer distance and long ion transfer distance.Herein,this paper aims to address the issue by introducing MXene through a simple and scalable method for assembling graphene and realizing ultrahigh P doping content.The findings reveal that MXene and P-C bonds have a "pillar effect" on the structure of graphene,and the P-C bond plays a primary role.In addition,N/P co-doping introduces abundant defects,providing more active sites for K^(+) storage and facilitating K^(+) adsorption.As expected,the developed ultrahigh phosphorous/nitrogen co-doped flexible reduced graphene oxide/MXene(NPrGM) electrode exhibits remarkable reversible discharge capacity(554 mA hg^(-1) at 0.05 A g^(-1)),impressive rate capability(178 mA h g^(-1) at 2 A g^(-1)),and robust cyclic stability(0.0005% decay per cycle after 10,000 cycles at 2 A g^(-1)).Furthermore,the assembled activated carbon‖NPrGM potassium-ion hybrid capacitor(PIHC) can deliver an impressive energy density of 131 W h kg^(-1) and stable cycling performance with 98.1% capacitance retention after5000 cycles at 1 A g^(-1).Such a new strategy will effectively promote the practical application of graphene materials in PIBs/PIHCs and open new avenues for the scalable development of flexible films based on two-dimensional materials for potential applications in energy storage,thermal interface,and electromagnetic shielding.展开更多
Sonoluminescence is more distinctly observed in phosphoric and sulfuric acid,which exhibit high viscosity and lower vapor pressures relative to water.Within an 85-wt%phosphoric acid solution saturated with argon(Ar),v...Sonoluminescence is more distinctly observed in phosphoric and sulfuric acid,which exhibit high viscosity and lower vapor pressures relative to water.Within an 85-wt%phosphoric acid solution saturated with argon(Ar),variations in the light-emitting regimes of bubbles were noted to correspond with increments in the driving acoustic intensity.Specifically,the bubbles were observed to perform a dance-like motion 2 cm below the multi-bubble sonoluminescence(MBSL)cluster,traversing a 25-mm^(2) grid during the camera exposure period.Spectral analysis conducted at the beginning of the experiment showed a gradual attenuation of CN(B^(2)Σ–X^(2)Σ)emission concurrent with a strengthening of Ar(4p–4s)atom emission lines.The application of a theoretical temperature model to the spectral data revealed that the internal temperature of the bubbles escalates swiftly upon their implosion.This study is instrumental in advancing the comprehension of the underlying mechanisms of sonoluminescence and in the formulation of a dynamic model for the behavior of the bubbles.展开更多
Eu^(2+) and Mn^(2+) co-activated CaAlSiN_(3) red phosphors were produced using the solid-state reaction tech⁃nique in a N2 environment.Excitation spectra,emission spectra,and diffuse reflection spectra were used to st...Eu^(2+) and Mn^(2+) co-activated CaAlSiN_(3) red phosphors were produced using the solid-state reaction tech⁃nique in a N2 environment.Excitation spectra,emission spectra,and diffuse reflection spectra were used to study the luminescence characteristics,energy gap,and thermal stability in detail.CaAlSiN_(3)∶Eu^(2+) exhibits an extended emission band when stimulated with 450 nm blue light,which is caused by the 4f65d to 4f7 transition of Eu^(2+).Similar⁃ly,CaAlSiN_(3)∶Mn^(2+) displays a wide emission band centered at 628 nm,which results from Mn^(2+)’s transition from 4T1(4G) to 6A1(6S).When the ions of Mn^(2+)were combined into CaAlSiN_(3)∶Eu^(2+),the photoluminescence intensity of Eu^(2+ )was greatly boosted because there was energy transfer and co-emission between Mn^(2+) and Eu^(2+).Beyond that,CaAlSiN_(3)∶Eu^(2+),Mn^(2+) emerges with splendid thermostability and high quantum efficiency,the quenching temperature surpasses 300℃,and the internal quantum efficiency is determined to be around 84.9%.The white LED was pack⁃aged with a combination of CaAlSiN_(3)∶Eu^(2+),Mn^(2+),LuAG∶Ce3+ and a blue chip.At a warm white-light corresponding color temperature(3009 K) with CIE coordinates(0.4223,0.3748),the color rendering index Ra has reached 93.2.CaAlSiN_(3)∶Eu^(2+),Mn^(2+) would have great application potential as a red-emitting phosphor for white LEDs.展开更多
A mixture of polydimethylsiloxane (PDMS) doped with phosphor particles can be found across diverse industries having different applications. This mixture plays a particularly important role in the field of lighting, w...A mixture of polydimethylsiloxane (PDMS) doped with phosphor particles can be found across diverse industries having different applications. This mixture plays a particularly important role in the field of lighting, white light-emitting diodes (LED's), flexible display devices, anti-counterfeiting (AC) solutions, luminescence thermometers and many types of sensors. The field of mechanoluminescence and biomedical are booming and there is also potential for visible light communication (VLC). In this comprehensive review, the basic characteristics of PDMS and a list of selected phosphors suitable for creating a mixture of PDMS and phosphor are presented. The summary and a detailed overview of the implemented applications of this perspective mixture over the last decade is presented as well.展开更多
The catalytic fast pyrolysis of cellulose impregnated with phosphoric acid (H3PO4) offers a promising method for the selective production of levoglucosenone (LGO),a valuable anhydrosugar product.However,the fundamenta...The catalytic fast pyrolysis of cellulose impregnated with phosphoric acid (H3PO4) offers a promising method for the selective production of levoglucosenone (LGO),a valuable anhydrosugar product.However,the fundamental mechanism for selective LGO formation is unclear.Herein,quantum chemistry calculations and catalytic fast pyrolysis experiments were performed to reveal the formation mechanism of LGO in H3PO4-catalyzed cellulose pyrolysis.H3PO4 significantly decreased the energy barriers of the pyrolytic reactions and altered the competitiveness of the LGO formation pathways,promoting LGO formation.Through different pathways in the non-catalytic and H3P04-catalyzed conditions,LGO is mainly produced from the primary decomposition of glucose units of cellulose and secondary conversion of levoglucosan.The major catalytic formation pathways of LGO comprise similar reactions,with dehydration at the 3-OH+2-H site as the rate-determining step.Importantly,secondary conversion of 1,4;3,6-dianhydro-α-D-glucopyranose is not feasible for LGO formation,in contrast to previous reports.In addition,a high degree of polymerization is beneficial for the selectivity of LGO formation in the catalytic process,because the glycosidic bond is important for the formation of the bicyclic structure (1,5-and1,6-acetal rings).展开更多
Sr3.96Al14025：Eu2＋,Dy3＋ long persistent materials with different weights of H3BO3 prepared by the high temper- ature solid-state reaction method were characterized by X-ray powder diffraction （XRD）, scanning elec...Sr3.96Al14025：Eu2＋,Dy3＋ long persistent materials with different weights of H3BO3 prepared by the high temper- ature solid-state reaction method were characterized by X-ray powder diffraction （XRD）, scanning electronic microscopy （SEM）, photoluminescence spectra （PL）, and thermoluminescence （TL）. The results of XRD indicate that the 3% addition of H3BO3 favorable for the formation of pure phase Sr4Al14025, and SrAl12O19 was generated when there is a low con- tent or high content of H3BO3. The average grain sizes of samples grow bigger with an increase of H3BO3. PL spectra show that the emission peak does not shift evidently and the emission intensity changes little, indicating that the different amount of H3BO3 has little influence on the crystal field. The decay characteristics and TL measurement show that H3BO3 affects the afterglow properties of Sr3.96Al14025：Eu2＋,Dy3＋, because the increasing H3BO3 leads to more defects in the Sr4Al14025 matrix.展开更多
A type of red luminescent Sr3Al2O6：Eu2＋, Dy3＋ phosphor powder is synthesised by sol-gel-combustion processing, with metal nitrates used as the source of metal ions and citric acid as a chelating agent of metal ions...A type of red luminescent Sr3Al2O6：Eu2＋, Dy3＋ phosphor powder is synthesised by sol-gel-combustion processing, with metal nitrates used as the source of metal ions and citric acid as a chelating agent of metal ions. By tracing the formation process of the sol-gel, it is found that it is necessary to reduce the amount of NO3 by dropping ethanol into the solution for forming a stable and homogeneous sol-gel. Thermogravimetric and Differential Scanning Calorimeter Analysis, x-ray diffractionmeter, scanning electron microscopy and photoluminescence spectroscopy are used to investigate the luminescent properties of the as-synthesised Sr3A1206：Eu2＋, Dy3＋. The results reveal that the Sr3Al2O6 crystallises completely when the combustion ash is sintered at 1250℃. The excitation and the emission spectra indicate that the excitation broadband lies mainly in a visible range and the phosphors emit a strong light at 618 nm under the excitation of 472 nm. The afterglow of （Sr0.94Eu0.03Dy0.03）3Al2O6 phosphors sintered at 1250℃ lasts for over 1000 s when the excited source is cut off.展开更多
Novel Y1-x-yVO4：xDy3＋, yBi3＋ （0.01 ≤ x ≤ 0.05,0 ≤ y ≤0.20） phosphors for light emitting diode （LED） were successfully synthesised by solid-state reaction. The calculation results of electronic structure sho...Novel Y1-x-yVO4：xDy3＋, yBi3＋ （0.01 ≤ x ≤ 0.05,0 ≤ y ≤0.20） phosphors for light emitting diode （LED） were successfully synthesised by solid-state reaction. The calculation results of electronic structure show that YVO4 has a direct band gap with 3 eV at G. The top of the valence band is dominated by O 2p state and the bottom of the conduction band is mainly composed of O 2p and V 3d states. An efficient yellow emission under near-ultraviolet （365 nm） excitation is observed. Compared with the pure YVO4：Dy3＋ samples, the Dy3＋, Bi3＋ co-doped samples show a more intensive emission peak （at 574 nm） and a new broad emission band （450-770 nm）, due to the 4F9/2 - 6H13/2 transition of Dy3＋ and the emission of the VO43-Bi3＋ complex respectively. The optimum chromaticity index of Y1-x-yVO4：xDy3＋, yBi3＋ （0.01 ≤ x ≤0.05,0 ≤y ≤ 0.20） is （0.447, 0.497）, which indicates that YVO4：Dy3＋, Bi3＋ has higher colour saturation than the commercial phosphor YAG： Ce3＋. The effects of concentration of Dy3＋, Bi3＋, electric states and the photoluminescence properties are discussed in details.展开更多
文摘A novel self-recoverable mechanoluminescent phosphor Ca_(5)Ga_(6)O_(14)∶Eu^(3+) was developed by the high-tem-perature solid-state reaction method,and its luminescence properties were investigated.Ca_(5)Ga_(6)O_(14)∶Eu^(3+)can produce red mechanoluminescence,and importantly,it shows good repeatability.The mechanoluminescence of Ca_(5)Ga_(6)O_(14)∶Eu^(3+) results from the piezoelectric field generated inside the material under stress,rather than the charge carriers stored in the traps,which can be confirmed by the multiple cycles of mechanoluminescence tests and heat treatment tests.The mechanoluminescence color can be turned from red to green by co-doping varied concentrations of Tb^(3+),which may be meaningful for encrypted letter writing.The encryption scheme for secure communication was devised by harnessing mechanoluminescence patterns in diverse shapes and ASCII codes,which shows good encryption performance.The results suggest that the mechanoluminescence phosphor Ca_(5)Ga_(6)O_(14)∶Eu^(3+),Tb^(3+)may be applied to the optical information encryption.
基金financially supported by the National Natural Science Foundation of China (52172192)the Young Top-Notch Talent of National Ten Thousand Talent Program (W03070054)。
文摘Graphene's large theoretical surface area and high conductivity make it an attractive anode material for potassium-ion batteries(PIBs).However,its practical application is hindered by small interlayer distance and long ion transfer distance.Herein,this paper aims to address the issue by introducing MXene through a simple and scalable method for assembling graphene and realizing ultrahigh P doping content.The findings reveal that MXene and P-C bonds have a "pillar effect" on the structure of graphene,and the P-C bond plays a primary role.In addition,N/P co-doping introduces abundant defects,providing more active sites for K^(+) storage and facilitating K^(+) adsorption.As expected,the developed ultrahigh phosphorous/nitrogen co-doped flexible reduced graphene oxide/MXene(NPrGM) electrode exhibits remarkable reversible discharge capacity(554 mA hg^(-1) at 0.05 A g^(-1)),impressive rate capability(178 mA h g^(-1) at 2 A g^(-1)),and robust cyclic stability(0.0005% decay per cycle after 10,000 cycles at 2 A g^(-1)).Furthermore,the assembled activated carbon‖NPrGM potassium-ion hybrid capacitor(PIHC) can deliver an impressive energy density of 131 W h kg^(-1) and stable cycling performance with 98.1% capacitance retention after5000 cycles at 1 A g^(-1).Such a new strategy will effectively promote the practical application of graphene materials in PIBs/PIHCs and open new avenues for the scalable development of flexible films based on two-dimensional materials for potential applications in energy storage,thermal interface,and electromagnetic shielding.
基金Project supported by the Scientific Research Project of Higher Education in the Inner Mongolia Autonomous Region,China(Grant No.NJZY23100)the Natural Science Foundation of Inner Mongolia Autonomous Region,China(Grant No.2024FX30)the 14th Five Year Plan Project for Education Science in Inner Mongolia Autonomous Region,China(Grant No.NGJGH2023205).
文摘Sonoluminescence is more distinctly observed in phosphoric and sulfuric acid,which exhibit high viscosity and lower vapor pressures relative to water.Within an 85-wt%phosphoric acid solution saturated with argon(Ar),variations in the light-emitting regimes of bubbles were noted to correspond with increments in the driving acoustic intensity.Specifically,the bubbles were observed to perform a dance-like motion 2 cm below the multi-bubble sonoluminescence(MBSL)cluster,traversing a 25-mm^(2) grid during the camera exposure period.Spectral analysis conducted at the beginning of the experiment showed a gradual attenuation of CN(B^(2)Σ–X^(2)Σ)emission concurrent with a strengthening of Ar(4p–4s)atom emission lines.The application of a theoretical temperature model to the spectral data revealed that the internal temperature of the bubbles escalates swiftly upon their implosion.This study is instrumental in advancing the comprehension of the underlying mechanisms of sonoluminescence and in the formulation of a dynamic model for the behavior of the bubbles.
文摘Eu^(2+) and Mn^(2+) co-activated CaAlSiN_(3) red phosphors were produced using the solid-state reaction tech⁃nique in a N2 environment.Excitation spectra,emission spectra,and diffuse reflection spectra were used to study the luminescence characteristics,energy gap,and thermal stability in detail.CaAlSiN_(3)∶Eu^(2+) exhibits an extended emission band when stimulated with 450 nm blue light,which is caused by the 4f65d to 4f7 transition of Eu^(2+).Similar⁃ly,CaAlSiN_(3)∶Mn^(2+) displays a wide emission band centered at 628 nm,which results from Mn^(2+)’s transition from 4T1(4G) to 6A1(6S).When the ions of Mn^(2+)were combined into CaAlSiN_(3)∶Eu^(2+),the photoluminescence intensity of Eu^(2+ )was greatly boosted because there was energy transfer and co-emission between Mn^(2+) and Eu^(2+).Beyond that,CaAlSiN_(3)∶Eu^(2+),Mn^(2+) emerges with splendid thermostability and high quantum efficiency,the quenching temperature surpasses 300℃,and the internal quantum efficiency is determined to be around 84.9%.The white LED was pack⁃aged with a combination of CaAlSiN_(3)∶Eu^(2+),Mn^(2+),LuAG∶Ce3+ and a blue chip.At a warm white-light corresponding color temperature(3009 K) with CIE coordinates(0.4223,0.3748),the color rendering index Ra has reached 93.2.CaAlSiN_(3)∶Eu^(2+),Mn^(2+) would have great application potential as a red-emitting phosphor for white LEDs.
基金European Union under the REFRESH-Research Excellence For REgion Sustainability and High-tech Industries project number CZ.10.03.01/00/22003/0000048 via the Operational Programme Just TransitionMinistry of Education,Youth,and Sports of the Czech Republic con-ducted by the VSB-Technical University of Ostrava,under grant no.SP2024/081+1 种基金projects CI-CECO(LA/P/0006/2020,UIDB/50011/2020&UIDP/50011/2020)and Di-giAqua(PTDC/EEI-EEE/0415/2021)financed by national funds through the(Portuguese Science and Technology Foundation/MCTES(FCT I.P.)).
文摘A mixture of polydimethylsiloxane (PDMS) doped with phosphor particles can be found across diverse industries having different applications. This mixture plays a particularly important role in the field of lighting, white light-emitting diodes (LED's), flexible display devices, anti-counterfeiting (AC) solutions, luminescence thermometers and many types of sensors. The field of mechanoluminescence and biomedical are booming and there is also potential for visible light communication (VLC). In this comprehensive review, the basic characteristics of PDMS and a list of selected phosphors suitable for creating a mixture of PDMS and phosphor are presented. The summary and a detailed overview of the implemented applications of this perspective mixture over the last decade is presented as well.
基金the National Natural Science Foundation of China(51576064,51776070)Beijing Nova Program(Z171100001117064)+2 种基金Beijing Natural Science Foundation(3172030)grants from the Fok Ying Tung Education Foundation(161051)Fundamental Research Funds for the Central Universities(2018QN057,2018ZD08)for financial support。
文摘The catalytic fast pyrolysis of cellulose impregnated with phosphoric acid (H3PO4) offers a promising method for the selective production of levoglucosenone (LGO),a valuable anhydrosugar product.However,the fundamental mechanism for selective LGO formation is unclear.Herein,quantum chemistry calculations and catalytic fast pyrolysis experiments were performed to reveal the formation mechanism of LGO in H3PO4-catalyzed cellulose pyrolysis.H3PO4 significantly decreased the energy barriers of the pyrolytic reactions and altered the competitiveness of the LGO formation pathways,promoting LGO formation.Through different pathways in the non-catalytic and H3P04-catalyzed conditions,LGO is mainly produced from the primary decomposition of glucose units of cellulose and secondary conversion of levoglucosan.The major catalytic formation pathways of LGO comprise similar reactions,with dehydration at the 3-OH+2-H site as the rate-determining step.Importantly,secondary conversion of 1,4;3,6-dianhydro-α-D-glucopyranose is not feasible for LGO formation,in contrast to previous reports.In addition,a high degree of polymerization is beneficial for the selectivity of LGO formation in the catalytic process,because the glycosidic bond is important for the formation of the bicyclic structure (1,5-and1,6-acetal rings).
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 21271048, 11147152, and 61106124)the Natural Science Fund of Zhanjiang Normal University of China (Grant No. QL1020)
文摘Sr3.96Al14025：Eu2＋,Dy3＋ long persistent materials with different weights of H3BO3 prepared by the high temper- ature solid-state reaction method were characterized by X-ray powder diffraction （XRD）, scanning electronic microscopy （SEM）, photoluminescence spectra （PL）, and thermoluminescence （TL）. The results of XRD indicate that the 3% addition of H3BO3 favorable for the formation of pure phase Sr4Al14025, and SrAl12O19 was generated when there is a low con- tent or high content of H3BO3. The average grain sizes of samples grow bigger with an increase of H3BO3. PL spectra show that the emission peak does not shift evidently and the emission intensity changes little, indicating that the different amount of H3BO3 has little influence on the crystal field. The decay characteristics and TL measurement show that H3BO3 affects the afterglow properties of Sr3.96Al14025：Eu2＋,Dy3＋, because the increasing H3BO3 leads to more defects in the Sr4Al14025 matrix.
基金Project supported by the Key Research Project of Science and Technology of Shanxi, Shanxi Province, China (Grant No 2007031141)the Natural Science Foundation of Shanxi Province, China (Grant No 2007011061)the Scientific Research Foundation of the Higher Education Institutions of Shanxi Province, China (Grant No 20080012)
文摘A type of red luminescent Sr3Al2O6：Eu2＋, Dy3＋ phosphor powder is synthesised by sol-gel-combustion processing, with metal nitrates used as the source of metal ions and citric acid as a chelating agent of metal ions. By tracing the formation process of the sol-gel, it is found that it is necessary to reduce the amount of NO3 by dropping ethanol into the solution for forming a stable and homogeneous sol-gel. Thermogravimetric and Differential Scanning Calorimeter Analysis, x-ray diffractionmeter, scanning electron microscopy and photoluminescence spectroscopy are used to investigate the luminescent properties of the as-synthesised Sr3A1206：Eu2＋, Dy3＋. The results reveal that the Sr3Al2O6 crystallises completely when the combustion ash is sintered at 1250℃. The excitation and the emission spectra indicate that the excitation broadband lies mainly in a visible range and the phosphors emit a strong light at 618 nm under the excitation of 472 nm. The afterglow of （Sr0.94Eu0.03Dy0.03）3Al2O6 phosphors sintered at 1250℃ lasts for over 1000 s when the excited source is cut off.
基金Project supported by the National Natural Science Foundation of China (Grant No. 10874061)
文摘Novel Y1-x-yVO4：xDy3＋, yBi3＋ （0.01 ≤ x ≤ 0.05,0 ≤ y ≤0.20） phosphors for light emitting diode （LED） were successfully synthesised by solid-state reaction. The calculation results of electronic structure show that YVO4 has a direct band gap with 3 eV at G. The top of the valence band is dominated by O 2p state and the bottom of the conduction band is mainly composed of O 2p and V 3d states. An efficient yellow emission under near-ultraviolet （365 nm） excitation is observed. Compared with the pure YVO4：Dy3＋ samples, the Dy3＋, Bi3＋ co-doped samples show a more intensive emission peak （at 574 nm） and a new broad emission band （450-770 nm）, due to the 4F9/2 - 6H13/2 transition of Dy3＋ and the emission of the VO43-Bi3＋ complex respectively. The optimum chromaticity index of Y1-x-yVO4：xDy3＋, yBi3＋ （0.01 ≤ x ≤0.05,0 ≤y ≤ 0.20） is （0.447, 0.497）, which indicates that YVO4：Dy3＋, Bi3＋ has higher colour saturation than the commercial phosphor YAG： Ce3＋. The effects of concentration of Dy3＋, Bi3＋, electric states and the photoluminescence properties are discussed in details.
