Well-ordered metal structures, i.e. arrays of nanosized tips on silver surface for studies of the luminescence enhancement of absorbed media with rare earth ions were used. These arrays were prepared by the metal evap...Well-ordered metal structures, i.e. arrays of nanosized tips on silver surface for studies of the luminescence enhancement of absorbed media with rare earth ions were used. These arrays were prepared by the metal evaporation on track membranes. Calculations of reso- nanee frequencies of tips regarded as semispheroids were done taking into account the interaction between dipoles of tips. They were used to discuss experimental results for media with Eu(NO3)3·6H2O salt basing on data for bulk silver dielectric function.展开更多
The luminescent enhancement effect of Na_5Eu(MoO_4)_4 by doping(WO_4)^(2-) has been studied. When the value x in Na_5Eu(Mo_(1-x)W_xO_4)_4 is in 0<x<0.21,its photoluminescent spectrum is near to that of Na_5Eu(Mo...The luminescent enhancement effect of Na_5Eu(MoO_4)_4 by doping(WO_4)^(2-) has been studied. When the value x in Na_5Eu(Mo_(1-x)W_xO_4)_4 is in 0<x<0.21,its photoluminescent spectrum is near to that of Na_5Eu(MoO_4)_4,but its luminescent intensity increases.When x=0.033,the intensity is increased by about 30%.According to the X-ray diffraction analysis,W ions get into the lattice and occupy the sites of the Mo ions.The change of crystal environment of Eu^(3+) may result in the luminescent enhancement.展开更多
High-reflectivity Al-based n-electrode is used to enhance the luminescence properties of InGaN-based 395nm flip-chip near-ultraviolet (UV) light-emitting diodes. The Al-only metal layer could form the Ohmic contact ...High-reflectivity Al-based n-electrode is used to enhance the luminescence properties of InGaN-based 395nm flip-chip near-ultraviolet (UV) light-emitting diodes. The Al-only metal layer could form the Ohmic contact on the plasma etched n-GaN by means of chemical pre-treatment, with the lowest specific contact resistance of 2.211 × 10^-5 Ω. cm2. The AI n-electrodes enhance light output power of the 395 nm flip-chip near-UV light-emitting diodes by more than 33% compared with the Ti/AI n-electrodes. Meanwhile, the electrical characteristics of these chips with two types of n-electrodes do not show any significant discrepancy. The near-field light distribution measurement of packaged chips confirms that the enhanced luminescence is ascribed to the high refleetivity of the Al electrodes in the UV region. After the accelerated aging test for over 1000 h, the luminous degradation of the packaged chips with Al n-electrodes is less than 3%, which proves the reliability of these chips with the Al-based electrodes. Our approach shows a simplified design and fabrication of high-refleetivity n-electrode for flip-chip near-UV light emitting diodes.展开更多
Objective:To evaluate the value of enhanced luminescence enzyme immunoassay in the diagnosis of Neisseria gonorrhea(NG) infection. Methods: Anti-catalase antibody for Neisseria gonorrheae combined with enhanced lumine...Objective:To evaluate the value of enhanced luminescence enzyme immunoassay in the diagnosis of Neisseria gonorrhea(NG) infection. Methods: Anti-catalase antibody for Neisseria gonorrheae combined with enhanced luminescence enzyme immunoassay were used to test for N. gonorrhea. Results: A minimum of 1×10^4/CFU of GC in genital tract secretions or urine could be detected with the technique of luminescence enzyme immunoassay. Conclusion : The enhanced luminescence enzyme immunoassay has the advantage of high sensitivity and specificity for diagnosing NG from genitourinary tract secretion and urine.展开更多
A red-emitting phosphor Ca_(2.91)Si_(2)O_(7):0.09Eu^(3+) with partial Al^(3+)/P^(5+) substitution on Si^(4+) was synthesized via a simple solid-state method,and the effects of the introduction of the M^(3+/5+)(M=Al,P)...A red-emitting phosphor Ca_(2.91)Si_(2)O_(7):0.09Eu^(3+) with partial Al^(3+)/P^(5+) substitution on Si^(4+) was synthesized via a simple solid-state method,and the effects of the introduction of the M^(3+/5+)(M=Al,P)ions on the crystal structure and photoluminescence performance of Ca_(2.91)Si_(2−x)M_(x)O_(7):0.09Eu^(3+) phosphors were investigated.The X-ray diffraction(XRD),energy-dispersive X-ray spectroscopy(EDS),and X-ray photoelectron spectroscopy(XPS)results revealed that the structure of Ca_(3)Si_(2)O_(7) remained the same after the introduction of Al^(3+) and P^(5+) ions.The characteristic emission of Eu^(3+)-doped Ca_(3)Si_(2−x)M_(x)O_(7) phosphors exhibited two main peaks at 617 nm(red)and 593 nm(orange)under excitation at 394 nm,which originated from the^(5)D_(0)→^(7)F_(2)and^(5)D_(0)→^(7)F_(1) electron transitions of Eu^(3+) ions.After the partial substitution of Al^(3+) and P^(5+),the red emission intensities of the Ca_(2.91)Si_(2)O_(7):0.09Eu^(3+) phosphors were significantly enhanced by 1.88-and 1.42-fold,respectively,which is attributed to the crystal-field effect around Eu^(3+).Meanwhile,the luminescence intensities of the Ca_(2.91)Si_(1.96)Al_(0.04)O_(7):0.09Eu^(3+) and Ca_(2.91)Si_(1.94)P_(0.06)O_(7):0.09Eu^(3+) phosphors at 210℃ were 79.36%and 77.53%of those at 30°C,respectively,indicating their excellent thermal stability.Moreover,the as-prepared Ca_(2.91)Si_(1.96)Al_(0.04)O_(7):0.09Eu^(3+)and Ca_(2.91)Si_(1.94)P_(0.06)O_(7):0.09Eu^(3+) red-emitting phosphors were combined with a near-ultraviolet chip of 395 nm to fabricate red-light-emitting diode(LED)and white(w)-LED devices with excellent chromaticity features.In summary,Al^(3+)/P^(5+)-substituted Ca_(2.91)Si_(2)O_(7):0.09Eu^(3+) can serve as red-emitting phosphors for applications in w-LEDs.展开更多
In order to improve the multi-ion cooperative transition, we proposed and exploited a novel nanoscale effect, namely the nanoshell effect in bulk materials. Based on the effect, an optimal material structure was desig...In order to improve the multi-ion cooperative transition, we proposed and exploited a novel nanoscale effect, namely the nanoshell effect in bulk materials. Based on the effect, an optimal material structure was designed by coating the surfaces of Ca F_(2):Yb^(3+)micron size particles with ZrO_(2). An about 2 times higher intensity of cooperative luminescence is observed upon laser excitation at 980 nm. Dynamical analysis exhibits that the novel effect plays a key role in improving the performance of cooperative transitions. Our results also suggest that the nanoshell effect in bulk materials is likely to be significant in some special cases, which have not been reported yet in the literature.展开更多
YPO4 and Eu doped YPO4 nanocrystals were prepared via a simple hydrothermal method. The phase purity, rnicrostructure, surface absorbed water and luminescence properties were characterized with X-ray diffraction (XRD...YPO4 and Eu doped YPO4 nanocrystals were prepared via a simple hydrothermal method. The phase purity, rnicrostructure, surface absorbed water and luminescence properties were characterized with X-ray diffraction (XRD), transmission electron microscopy (TEM), fluorescence spectrum, infrared spectroscopy, Raman spectroscopy and thermogravimetry analysis(TGA). Combined with XRD and TEM analysis, it was found that YPO4 nanocrystals crystallized into a single phase of tetragonal (141/amd) zircon structure. YPO4 nanocrystals showed a size reduction with the reaction temperature decreasing. Considering the XRD, IR and Raman results, a lattice expansion and the unit cell symmetry enhancement were observed with the particle size decreasing. A dipole to dipole interaction model was applied to investigate the relationship of the variation of microstrucmre and the particle size. The emission spectrum of Eu doped YPO4 nanocrystals was also presented and the emission bands were clearly ascribed to the f to f transitions of Eu^3+.展开更多
Pr-doped metal oxide polycrystalline transparent ceramics are highly desirable for photothermal window systems served in extreme environments;however,obtaining efficient photoluminescence(PL)together with high transpa...Pr-doped metal oxide polycrystalline transparent ceramics are highly desirable for photothermal window systems served in extreme environments;however,obtaining efficient photoluminescence(PL)together with high transparency in these ceramics is still posing serious challenges,which undoubtedly limits their applications.Here,Pr-doped Y_(2)Zr_(2)O_(7)(YZO)transparent ceramics,as an illustrative example,are prepared by a solid-state reaction and vacuum sintering method.Owing to the elimination of defect clusters[Pr_(Y)^(4+)-O^(2-)Pr_(Y)^(4+)]and[Pr_(Y)^(4+)-e′]without the introduction of impurities and additional defects,the fabricated YZO:Pr ceramics exhibit high transparency(74%)and efficient PL(39-fold enhanced)after air annealing plus vacuum re-annealing treatment.Moreover,upon 295/450 nm excitation,the emission bands(blue,green,red,and dark red)from YZO:Pr ceramics present different temperature-dependent properties due to the thermalquenching channel generated by the intervalence charge transfer(IVCT)state between Pr_(Y)^(4+)and Zr^(4+)ions.Furthermore,a self-calibrated temperature feedback window with the same fluorescence intensity ratio(FIR)model(I_(613)/I_(503),where I represents the intensity)under different excitation light sources(295 and 450 nm)is designed.The developed photothermal window operated in a wide temperature range(303-663 K)shows relatively high sensitivities(absolute sensitivity(Sa)and relative sensitivity(S)reach 0.008 K^(-1)at 663 K and 0.47%K^(-1)at 363 K,respectively),high repeatability(>98%),and low temperature uncertainty(T<3.2 K).This work presents a paradigm for achieving enhanced PL along with elevated transparency of lanthanide(Ln)-doped ceramics through vacuum re-annealing treatment engineering and demonstrates their promising potential for photothermal window systems.展开更多
The preparation of high-efficiency phosphor is the key to the construction of white light-emitting diode(WLED)devices and their application in indoor photovoltaics.Compared with YVO_(4),InVO_(4)is not suitable as the ...The preparation of high-efficiency phosphor is the key to the construction of white light-emitting diode(WLED)devices and their application in indoor photovoltaics.Compared with YVO_(4),InVO_(4)is not suitable as the host material of lanthanide ions because of its strong self-luminescence.Here,the work focused on combining the broadband emission from InVO_(4)and the red luminescence from YVO_(4):Eu^(3+)to obtain enhanced and stable multicolor luminescence.The band structure,density of state,and optical properties were studied by density functional theory.The spectral configuration of YVO_(4):In^(3+)/Eu^(3+)with(112)surface appears to be broadening and redshifts with increasing layer number.When the In^(3+)concentration is 3.5 mol%,the YVO_(4):30%Eu^(3+)/In^(3+)emits the strongest light.The Judd-Ofelt parameterΩ2 of YVO_(4):In^(3+)/Eu^(3+)increases with increaing In^(3+)concentration,indicating that the symmetry decreases.By adjusting In^(3+)/Eu^(3+)contents,the YVO_(4):In^(3+)/Eu^(3+)not only can emit white light with a color rendering index of 95,but also can be used as high-efficiency red phosphor to build WLED devices with blue emitting N/Tb codoped carbon quantum dots(CQDs-N:Tb^(3+))and green emitting MOF:Tb^(3+)(MOF=metal organic framework),for which the color rendering index can also reach 95 and the color temperature is 5549 K.The manufactured WLED devices were further used to excite the silicon solar cell and make it show good photoelectric characteristics.展开更多
The opal photonic crystals(PCs) were assembled by vertical deposition of polystyrene microspheres(PS), in which Yb3+, Er3+ co-doped ZnO powders were deposited on the surface of PC films. The phase, structure and morph...The opal photonic crystals(PCs) were assembled by vertical deposition of polystyrene microspheres(PS), in which Yb3+, Er3+ co-doped ZnO powders were deposited on the surface of PC films. The phase, structure and morphology of the obtained samples were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM) and transmission electron microscope(TEM). The performance of up-conversion photoluminescence(UCPL) was investigated by fluorescence spectrophotometer. The up-conversion(UC) emission of Zn O:Yb3+/Er3+ on the PC surface is notably enhanced when the UC emission wavelength is overlapped with the photonic bandgaps of opals, which is attributed to Bragg reflection of photonic bandgap. The results show that PCs may have potential applications in the enhancement of UCPL and optoelectronic devices.展开更多
CaMoO_(4):Eu^(3+)and CaMoO_(4):Eu^(3+),A+(A=Li,Na,K)phosphors for light-emitting diode(LED)applications have been prepared by microwave sintering method(MSM),and their structure and luminescence properties are investi...CaMoO_(4):Eu^(3+)and CaMoO_(4):Eu^(3+),A+(A=Li,Na,K)phosphors for light-emitting diode(LED)applications have been prepared by microwave sintering method(MSM),and their structure and luminescence properties are investigated.The influences of microwave reaction time and concentration of different kinds of charge compensation A+and Eu^(3+)on luminescence have also been discussed.The samples emit a red luminescence at 615 nm attributed to the^(5)D0→^(7)F2 transition of Eu^(3+)under 464 nm excitation.It is observed that adding charge compensation A+in the sample synthesis increases luminescence intensity.The optimized sample made with 32 mol%Li+and 32 mol%Eu^(3+)has an enhancement factor of 4 in photoluminescence compared to the sample made without charge compensation.The CIE(Commission Internationale de l'Eclairage)coordinates of Ca0.36MoO_(4):0.32Eu^(3+),0.32Li+are x=0.661 and y=0.339,which indicate that the obtained phosphor can be a promising red color candidate for white LED fabrications.展开更多
An Si/O patterned shell array was fabricated by a technique utilizing nanosphere self assembly and reactive pressure pulsed laser deposition.The nanostructure produced by this technique enhanced the luminescence inten...An Si/O patterned shell array was fabricated by a technique utilizing nanosphere self assembly and reactive pressure pulsed laser deposition.The nanostructure produced by this technique enhanced the luminescence intensity by a factor of three compared with that of a flat film.The amount of enhance-ment observed coincided well with the expected enhancement by simulation.The technique in this paper provided a flexible,designable and compatible approach to luminescence enhancement.展开更多
After trace Sm^3+ ions and Gd^3+ ions doping, the emission intensity of red phosphors Y2O2S: Eu^3 + was enhanced and the voltage character (relation between emission intensity and excitation voltage) was improve...After trace Sm^3+ ions and Gd^3+ ions doping, the emission intensity of red phosphors Y2O2S: Eu^3 + was enhanced and the voltage character (relation between emission intensity and excitation voltage) was improved while the other properties of physics and chemistry were not changed. The origins of enhancement and improvement are discussed. Probably the distortion and the defect of crystals are decreased by the substitution of Gd^3+ for Y^3+ instead of Eu^3+ for Y^3+ , and thus the Eu^3+ crystal field is improved, and radiationless process and energy loss resulted from crystal defect are weakened, which leads to increased luminescence intensity and voltage character improvement. The overlapping fluorescent spectra of Y2O2S: Sm^3+ emission and Y2O2S:Eu^3+ excitation as well as Eu^3 + excitation spectra transitions spectra lead to energy transfer from Sm^3 + sensitization of Sm^3+ ions fectively. containing Sm^3+ excitation the possibility of resonance ions to Eu^3+ ions, and the to Eu^3+ ions is achieved effectively.展开更多
Optically transparent Er3+/Tm3+/Yb3+ tri-doped oxyfluoride tellurite based nano-crystallized glass ceramics with the batching composition of 73TeO2-15ZnO-7ZnF2-3YF3-1.5YbF3-0.3ErF3-0.2TmF3 (mol%) is prepared by a...Optically transparent Er3+/Tm3+/Yb3+ tri-doped oxyfluoride tellurite based nano-crystallized glass ceramics with the batching composition of 73TeO2-15ZnO-7ZnF2-3YF3-1.5YbF3-0.3ErF3-0.2TmF3 (mol%) is prepared by a conventional melting quenching and the subsequent heat treatment processes. The sizes of grown nano-crystals in glass matrix appear to be smaller than 100 nm from the scanning electron mi- croscope measurement. Visible up-conversion luminescence of the as melted glass and glass ceramics is investigated. The three-color up-conversion luminescence intensities by 980-nm pumping are increased significantly due to the heat treatment, and the blue intensity increases with a higher magnitude than other wavelengths after heat treatment.展开更多
Infrared-to-visible upconverted luminescent spectra of Er3 t and La3 t codoped Y2O3 powders are investigated.By introducing La3 t ions, the upconversion green radiation is found to be greatly enhanced when compared wi...Infrared-to-visible upconverted luminescent spectra of Er3 t and La3 t codoped Y2O3 powders are investigated.By introducing La3 t ions, the upconversion green radiation is found to be greatly enhanced when compared with the powders with La3 t absent. Such enhancement can be attributed to the modification of the local symmetry surrounding the Er3 t ion, which benefits the intra-4f transitions of Er3 t ion, and the decreasing interaction between Er3 t ions, which suppresses the energy transfer process4F7∕2t 4I11∕2→ 4F9∕2t 4F9∕2.展开更多
文摘Well-ordered metal structures, i.e. arrays of nanosized tips on silver surface for studies of the luminescence enhancement of absorbed media with rare earth ions were used. These arrays were prepared by the metal evaporation on track membranes. Calculations of reso- nanee frequencies of tips regarded as semispheroids were done taking into account the interaction between dipoles of tips. They were used to discuss experimental results for media with Eu(NO3)3·6H2O salt basing on data for bulk silver dielectric function.
文摘The luminescent enhancement effect of Na_5Eu(MoO_4)_4 by doping(WO_4)^(2-) has been studied. When the value x in Na_5Eu(Mo_(1-x)W_xO_4)_4 is in 0<x<0.21,its photoluminescent spectrum is near to that of Na_5Eu(MoO_4)_4,but its luminescent intensity increases.When x=0.033,the intensity is increased by about 30%.According to the X-ray diffraction analysis,W ions get into the lattice and occupy the sites of the Mo ions.The change of crystal environment of Eu^(3+) may result in the luminescent enhancement.
基金Supported by the National Key Research and Development Program of China under Grant Nos 2016YFB0400901 and2016YFB0400804the Key Laboratory of Infrared Imaging Materials and Detectors of Shanghai Institute of Technical Physics of Chinese Academy of Sciences under Grant NoⅡMDKFJJ-15-07+1 种基金the National Natural Science Foundation of China under Grant Nos 61675079,11574166 and 61377034the China Postdoctoral Foundation under Grant No 2016M602287
文摘High-reflectivity Al-based n-electrode is used to enhance the luminescence properties of InGaN-based 395nm flip-chip near-ultraviolet (UV) light-emitting diodes. The Al-only metal layer could form the Ohmic contact on the plasma etched n-GaN by means of chemical pre-treatment, with the lowest specific contact resistance of 2.211 × 10^-5 Ω. cm2. The AI n-electrodes enhance light output power of the 395 nm flip-chip near-UV light-emitting diodes by more than 33% compared with the Ti/AI n-electrodes. Meanwhile, the electrical characteristics of these chips with two types of n-electrodes do not show any significant discrepancy. The near-field light distribution measurement of packaged chips confirms that the enhanced luminescence is ascribed to the high refleetivity of the Al electrodes in the UV region. After the accelerated aging test for over 1000 h, the luminous degradation of the packaged chips with Al n-electrodes is less than 3%, which proves the reliability of these chips with the Al-based electrodes. Our approach shows a simplified design and fabrication of high-refleetivity n-electrode for flip-chip near-UV light emitting diodes.
文摘Objective:To evaluate the value of enhanced luminescence enzyme immunoassay in the diagnosis of Neisseria gonorrhea(NG) infection. Methods: Anti-catalase antibody for Neisseria gonorrheae combined with enhanced luminescence enzyme immunoassay were used to test for N. gonorrhea. Results: A minimum of 1×10^4/CFU of GC in genital tract secretions or urine could be detected with the technique of luminescence enzyme immunoassay. Conclusion : The enhanced luminescence enzyme immunoassay has the advantage of high sensitivity and specificity for diagnosing NG from genitourinary tract secretion and urine.
基金This work was financially supported by the Department of Science and Technology of Sichuan Province(No.2020YJ0157).
文摘A red-emitting phosphor Ca_(2.91)Si_(2)O_(7):0.09Eu^(3+) with partial Al^(3+)/P^(5+) substitution on Si^(4+) was synthesized via a simple solid-state method,and the effects of the introduction of the M^(3+/5+)(M=Al,P)ions on the crystal structure and photoluminescence performance of Ca_(2.91)Si_(2−x)M_(x)O_(7):0.09Eu^(3+) phosphors were investigated.The X-ray diffraction(XRD),energy-dispersive X-ray spectroscopy(EDS),and X-ray photoelectron spectroscopy(XPS)results revealed that the structure of Ca_(3)Si_(2)O_(7) remained the same after the introduction of Al^(3+) and P^(5+) ions.The characteristic emission of Eu^(3+)-doped Ca_(3)Si_(2−x)M_(x)O_(7) phosphors exhibited two main peaks at 617 nm(red)and 593 nm(orange)under excitation at 394 nm,which originated from the^(5)D_(0)→^(7)F_(2)and^(5)D_(0)→^(7)F_(1) electron transitions of Eu^(3+) ions.After the partial substitution of Al^(3+) and P^(5+),the red emission intensities of the Ca_(2.91)Si_(2)O_(7):0.09Eu^(3+) phosphors were significantly enhanced by 1.88-and 1.42-fold,respectively,which is attributed to the crystal-field effect around Eu^(3+).Meanwhile,the luminescence intensities of the Ca_(2.91)Si_(1.96)Al_(0.04)O_(7):0.09Eu^(3+) and Ca_(2.91)Si_(1.94)P_(0.06)O_(7):0.09Eu^(3+) phosphors at 210℃ were 79.36%and 77.53%of those at 30°C,respectively,indicating their excellent thermal stability.Moreover,the as-prepared Ca_(2.91)Si_(1.96)Al_(0.04)O_(7):0.09Eu^(3+)and Ca_(2.91)Si_(1.94)P_(0.06)O_(7):0.09Eu^(3+) red-emitting phosphors were combined with a near-ultraviolet chip of 395 nm to fabricate red-light-emitting diode(LED)and white(w)-LED devices with excellent chromaticity features.In summary,Al^(3+)/P^(5+)-substituted Ca_(2.91)Si_(2)O_(7):0.09Eu^(3+) can serve as red-emitting phosphors for applications in w-LEDs.
基金Project supported by the National Natural Science Foundation of China(12174150)the Open Fund of the State Key Laboratory on Integrated Optoelectronics。
文摘In order to improve the multi-ion cooperative transition, we proposed and exploited a novel nanoscale effect, namely the nanoshell effect in bulk materials. Based on the effect, an optimal material structure was designed by coating the surfaces of Ca F_(2):Yb^(3+)micron size particles with ZrO_(2). An about 2 times higher intensity of cooperative luminescence is observed upon laser excitation at 980 nm. Dynamical analysis exhibits that the novel effect plays a key role in improving the performance of cooperative transitions. Our results also suggest that the nanoshell effect in bulk materials is likely to be significant in some special cases, which have not been reported yet in the literature.
文摘YPO4 and Eu doped YPO4 nanocrystals were prepared via a simple hydrothermal method. The phase purity, rnicrostructure, surface absorbed water and luminescence properties were characterized with X-ray diffraction (XRD), transmission electron microscopy (TEM), fluorescence spectrum, infrared spectroscopy, Raman spectroscopy and thermogravimetry analysis(TGA). Combined with XRD and TEM analysis, it was found that YPO4 nanocrystals crystallized into a single phase of tetragonal (141/amd) zircon structure. YPO4 nanocrystals showed a size reduction with the reaction temperature decreasing. Considering the XRD, IR and Raman results, a lattice expansion and the unit cell symmetry enhancement were observed with the particle size decreasing. A dipole to dipole interaction model was applied to investigate the relationship of the variation of microstrucmre and the particle size. The emission spectrum of Eu doped YPO4 nanocrystals was also presented and the emission bands were clearly ascribed to the f to f transitions of Eu^3+.
基金supported by the National Natural Science Foundation of China(U21A20441)the Nuclear Power Development Programme,the Key Research and Development Program of Sichuan Province(2021YFG0375)+2 种基金the Key Science and Technology Project of Sichuan Province(2020ZDZX0012)the Science and Technology Planning Project of Dazhou(21DWHZ0005)the Cooperation Project of Sichuan University and Dazhou(2021CDDZ-02).
文摘Pr-doped metal oxide polycrystalline transparent ceramics are highly desirable for photothermal window systems served in extreme environments;however,obtaining efficient photoluminescence(PL)together with high transparency in these ceramics is still posing serious challenges,which undoubtedly limits their applications.Here,Pr-doped Y_(2)Zr_(2)O_(7)(YZO)transparent ceramics,as an illustrative example,are prepared by a solid-state reaction and vacuum sintering method.Owing to the elimination of defect clusters[Pr_(Y)^(4+)-O^(2-)Pr_(Y)^(4+)]and[Pr_(Y)^(4+)-e′]without the introduction of impurities and additional defects,the fabricated YZO:Pr ceramics exhibit high transparency(74%)and efficient PL(39-fold enhanced)after air annealing plus vacuum re-annealing treatment.Moreover,upon 295/450 nm excitation,the emission bands(blue,green,red,and dark red)from YZO:Pr ceramics present different temperature-dependent properties due to the thermalquenching channel generated by the intervalence charge transfer(IVCT)state between Pr_(Y)^(4+)and Zr^(4+)ions.Furthermore,a self-calibrated temperature feedback window with the same fluorescence intensity ratio(FIR)model(I_(613)/I_(503),where I represents the intensity)under different excitation light sources(295 and 450 nm)is designed.The developed photothermal window operated in a wide temperature range(303-663 K)shows relatively high sensitivities(absolute sensitivity(Sa)and relative sensitivity(S)reach 0.008 K^(-1)at 663 K and 0.47%K^(-1)at 363 K,respectively),high repeatability(>98%),and low temperature uncertainty(T<3.2 K).This work presents a paradigm for achieving enhanced PL along with elevated transparency of lanthanide(Ln)-doped ceramics through vacuum re-annealing treatment engineering and demonstrates their promising potential for photothermal window systems.
基金supported by the National Natural Science Foundation of China(No.22271080).
文摘The preparation of high-efficiency phosphor is the key to the construction of white light-emitting diode(WLED)devices and their application in indoor photovoltaics.Compared with YVO_(4),InVO_(4)is not suitable as the host material of lanthanide ions because of its strong self-luminescence.Here,the work focused on combining the broadband emission from InVO_(4)and the red luminescence from YVO_(4):Eu^(3+)to obtain enhanced and stable multicolor luminescence.The band structure,density of state,and optical properties were studied by density functional theory.The spectral configuration of YVO_(4):In^(3+)/Eu^(3+)with(112)surface appears to be broadening and redshifts with increasing layer number.When the In^(3+)concentration is 3.5 mol%,the YVO_(4):30%Eu^(3+)/In^(3+)emits the strongest light.The Judd-Ofelt parameterΩ2 of YVO_(4):In^(3+)/Eu^(3+)increases with increaing In^(3+)concentration,indicating that the symmetry decreases.By adjusting In^(3+)/Eu^(3+)contents,the YVO_(4):In^(3+)/Eu^(3+)not only can emit white light with a color rendering index of 95,but also can be used as high-efficiency red phosphor to build WLED devices with blue emitting N/Tb codoped carbon quantum dots(CQDs-N:Tb^(3+))and green emitting MOF:Tb^(3+)(MOF=metal organic framework),for which the color rendering index can also reach 95 and the color temperature is 5549 K.The manufactured WLED devices were further used to excite the silicon solar cell and make it show good photoelectric characteristics.
基金supported by the National Natural Science Foundation of China(No.61274064)
文摘The opal photonic crystals(PCs) were assembled by vertical deposition of polystyrene microspheres(PS), in which Yb3+, Er3+ co-doped ZnO powders were deposited on the surface of PC films. The phase, structure and morphology of the obtained samples were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM) and transmission electron microscope(TEM). The performance of up-conversion photoluminescence(UCPL) was investigated by fluorescence spectrophotometer. The up-conversion(UC) emission of Zn O:Yb3+/Er3+ on the PC surface is notably enhanced when the UC emission wavelength is overlapped with the photonic bandgaps of opals, which is attributed to Bragg reflection of photonic bandgap. The results show that PCs may have potential applications in the enhancement of UCPL and optoelectronic devices.
基金supported by the National Natural Science Foundation of China(No.21271074)teamwork projects funded by Guangdong Natural Science Foundation(No.S2013030012842)CAS-Foshan Cooperation Funding Program(No.2012HY100685).
文摘CaMoO_(4):Eu^(3+)and CaMoO_(4):Eu^(3+),A+(A=Li,Na,K)phosphors for light-emitting diode(LED)applications have been prepared by microwave sintering method(MSM),and their structure and luminescence properties are investigated.The influences of microwave reaction time and concentration of different kinds of charge compensation A+and Eu^(3+)on luminescence have also been discussed.The samples emit a red luminescence at 615 nm attributed to the^(5)D0→^(7)F2 transition of Eu^(3+)under 464 nm excitation.It is observed that adding charge compensation A+in the sample synthesis increases luminescence intensity.The optimized sample made with 32 mol%Li+and 32 mol%Eu^(3+)has an enhancement factor of 4 in photoluminescence compared to the sample made without charge compensation.The CIE(Commission Internationale de l'Eclairage)coordinates of Ca0.36MoO_(4):0.32Eu^(3+),0.32Li+are x=0.661 and y=0.339,which indicate that the obtained phosphor can be a promising red color candidate for white LED fabrications.
基金Supported by the National Basic Research Program of China ("973" Project) (Grant No. 2002CB613505)the National Nature Science Foundation of China (Grant No. 90206046)
文摘An Si/O patterned shell array was fabricated by a technique utilizing nanosphere self assembly and reactive pressure pulsed laser deposition.The nanostructure produced by this technique enhanced the luminescence intensity by a factor of three compared with that of a flat film.The amount of enhance-ment observed coincided well with the expected enhancement by simulation.The technique in this paper provided a flexible,designable and compatible approach to luminescence enhancement.
文摘After trace Sm^3+ ions and Gd^3+ ions doping, the emission intensity of red phosphors Y2O2S: Eu^3 + was enhanced and the voltage character (relation between emission intensity and excitation voltage) was improved while the other properties of physics and chemistry were not changed. The origins of enhancement and improvement are discussed. Probably the distortion and the defect of crystals are decreased by the substitution of Gd^3+ for Y^3+ instead of Eu^3+ for Y^3+ , and thus the Eu^3+ crystal field is improved, and radiationless process and energy loss resulted from crystal defect are weakened, which leads to increased luminescence intensity and voltage character improvement. The overlapping fluorescent spectra of Y2O2S: Sm^3+ emission and Y2O2S:Eu^3+ excitation as well as Eu^3 + excitation spectra transitions spectra lead to energy transfer from Sm^3 + sensitization of Sm^3+ ions fectively. containing Sm^3+ excitation the possibility of resonance ions to Eu^3+ ions, and the to Eu^3+ ions is achieved effectively.
基金supported by the National"863"Project of China(No.2007AA03Z441)the National Natural Science Foundation of China(Nos.50672107 and 60607014)
文摘Optically transparent Er3+/Tm3+/Yb3+ tri-doped oxyfluoride tellurite based nano-crystallized glass ceramics with the batching composition of 73TeO2-15ZnO-7ZnF2-3YF3-1.5YbF3-0.3ErF3-0.2TmF3 (mol%) is prepared by a conventional melting quenching and the subsequent heat treatment processes. The sizes of grown nano-crystals in glass matrix appear to be smaller than 100 nm from the scanning electron mi- croscope measurement. Visible up-conversion luminescence of the as melted glass and glass ceramics is investigated. The three-color up-conversion luminescence intensities by 980-nm pumping are increased significantly due to the heat treatment, and the blue intensity increases with a higher magnitude than other wavelengths after heat treatment.
基金financially supported by the Nature Science Foundation of Zhejiang Province under Grant No.LQ13F050003
文摘Infrared-to-visible upconverted luminescent spectra of Er3 t and La3 t codoped Y2O3 powders are investigated.By introducing La3 t ions, the upconversion green radiation is found to be greatly enhanced when compared with the powders with La3 t absent. Such enhancement can be attributed to the modification of the local symmetry surrounding the Er3 t ion, which benefits the intra-4f transitions of Er3 t ion, and the decreasing interaction between Er3 t ions, which suppresses the energy transfer process4F7∕2t 4I11∕2→ 4F9∕2t 4F9∕2.