We synthesized reddish-orange luminescent La_(10)W_(22)O_(81)(LWO):Sm^(3+)microphosphors by hydrothermalassisted solid-state reaction.X-ray diffraction analysis reveals that all the studied phosphors crystallize in an...We synthesized reddish-orange luminescent La_(10)W_(22)O_(81)(LWO):Sm^(3+)microphosphors by hydrothermalassisted solid-state reaction.X-ray diffraction analysis reveals that all the studied phosphors crystallize in an orthorhombic structure in the Pbcn space group(60),Field emission scanning electron microscopy indicates that the LWO:1.5 mol%Sm^(3+)phosphor displays a smooth-surfaced hexagonal rod-like shape,with a closed shape at both ends,and high-resolution transmission electron microscopy demonstrates a robust crystalline structure.The chemical composition and valence states of the phosphor were investigated using X-ray photoelectron spectroscopy.At 403 nm excitation,LWO:1.5 mol%Sm3+exhibits maximum intensity with the strongest band at 596 nm(^(4)G_(5/2)→^(6)H_(7/2))in the reddish-orange region.The intensity of Sm^(3+)emission decreases beyond 1.5 mol%owing to concentration quenching regulated by dipole-quadrupole interaction between Sm^(3+)ions.The optimized microphosphor LWO:1.5 mol%Sm^(3+)exhibits color coordinates(0.5760,0.4207),which is close to that of the Amber LED-NSPAR 70 BS(0.570,0.420),displaying the highest color purity of 99.2%and correlated color temperature of 1694 K.In addition,both breast cancer cells MCF-7 and normal lung fibroblasts WI-38 were tested for toxicity with the optimized microphosphor.It is found that the LWO:1.5 Sm^(3+)microphosphor is extremely toxic to cancer cells,but not to normal cells.Based on these results,LWO:Sm^(3+)microphosphor can serve as a biomedical candidate for the treatment of cancer,as well as a potential multicolor emitting material for w-LEDs.展开更多
High-quality quantum dots(QDs)possess superior electroluminescent efficiencies and ultra-narrow emission linewidths are essential for realizing ultra-high definition QD light-emitting diodes(QLEDs).However,the synthes...High-quality quantum dots(QDs)possess superior electroluminescent efficiencies and ultra-narrow emission linewidths are essential for realizing ultra-high definition QD light-emitting diodes(QLEDs).However,the synthesis of such QDs remains challenging.In this study,we present a facile high-temperature successive ion layer adsorption and reaction(HT-SILAR)strategy for the growth of precisely tailored Zn_(1-x)Cd_(x)Se/ZnSe shells,and the consequent production of high-quality,large-particle,alloyed red CdZnSe/Zn_(1-x)Cd_(x)Se/ZnSe/ZnS/CdZnS QDs.The transitional Zn1 xCdxSe/ZnSe shells serve to effectively suppress heavy hole energy level splitting and weaken the exciton-longitudinal optical phonon coupling of QDs,thus facilitating the formation of highly luminescent QDs with a near-unity photoluminescence quantum yield of 97.8%and narrow emission with a full width at half maximum of 17.1 nm.In addition,the introduction of transitional shells can extend the particle size of QDs to 19.0 nm,which is beneficial for efficient carrier recombination and reduced Joule heating in QD-based LEDs.As a result,the fabricated QLEDs can achieve a record external quantum efficiency of 38.2%,luminance over 120,000 cd m^(-2),and exceptional operational stability T95(tested at 1,000 cd m^(-2))of 24,100 h.These findings provide new ave-nues for synthesizing high-quality QDs with high color purity.展开更多
The development and enrichment of organic materials with narrowband emission in longer wavelength regions beyond 515 nm still remains a great challenge.Herein,a synthetic methodology for narrowband emission materials ...The development and enrichment of organic materials with narrowband emission in longer wavelength regions beyond 515 nm still remains a great challenge.Herein,a synthetic methodology for narrowband emission materials has been proposed to functionalize multiple resonance(MR)skeletons and generate a universal building block,namely,the key intermediate DtCzB-Bpin,which can be utilized to construct multifarious thermally activated delayed fluorescence(TADF)materials with high color purity through a simple one-step Suzuki coupling reaction.Based on this unique synthetic strategy,a series of efficient narrowband green TADF emitters has been constructed by localized attachment of 1,3,5-triazine and pyrimidine derivatives-based acceptors onto B–N-containing MR frameworks with 1,3-bis(3,6-di-tertbutylcarbazol-9-yl)benzene(DtCz)as the ligand.The precise modulation of the acceptor is an intelligent approach to achieve bathochromic shift and narrowband emission simultaneously.The DtCzB-TPTRZbased organic light-emitting diode(OLED)exhibits pure green emission with Commission Internationale de L’Eclairage(CIE)coordinates of(0.23,0.68),a maximum external quantum efficiency(EQE)of 30.6%,and relatively low efficiency roll-off.展开更多
A series of orange-red light emitting Ca_(2)MgSi_(2)O_(7):Sm^(3+)nanopowders were fabricated via low-cost ecofriendly green combustion technique using Aloe vera gel as fuel.The phase purity of the samples were confirm...A series of orange-red light emitting Ca_(2)MgSi_(2)O_(7):Sm^(3+)nanopowders were fabricated via low-cost ecofriendly green combustion technique using Aloe vera gel as fuel.The phase purity of the samples were confirmed by the powder X-ray diffraction(PXRD)technique.Pure single-phase tetragonal structure is observed from the PXRD results with no additional impurity peaks.The band gap energy of the fabricated powders was estimated by diffuse reflectance spectra(DRS)and is found to be in the range of 4.01-5.98 eV.A high resolution scanning electron microscope(SEM)was used to study the morphological behaviour of the samples.Honeycomb-like structures are observed from the SEM results.The particle size was evaluated by transmission electron microscopy(TEM)and is found to be~50 nm.The interplanar distance is found to be 0.53 nm.Photoluminescence properties were systematically studied in detail.The phosphors are successfully excited at 403 nm NUV light,producing reddish-orange characteristic emission.The emission peaks are centered at 558(^(4)G_(5/2)→^(6)H_(5/2)),607(^(4)G_(5/2)→^(6)H_(7/2))and 645 nm(^(4)G_(5/2)→^(6)H_(9/2)),respectively.Among the observed peaks the red emanation(^(4)G_(5/2)→^(6)H_(7/2))is stronger than the orange emission(^(4)G_(5/2)→^(6)H_(5/2))in the current investigation.The photoluminescent concentration quenching is noticed above 5 mol%Sm^(3+)ion doping content.The dipole-dipole interaction resulting in cross relaxation is found to be the principal cause of concentration quenching mechanism.The color features such as Commission Internationale de I’Eclairage(CIE)and correlated color temperature(CCT)were studied in detail.The optimized chromaticity coordinates were estimated to be(0.6363,0.3632),which fall in the reddish-orange region.The average CCT value obtained is 3362 K.The average color purity is found to be~82%.Sm^(3+)incorporated Ca_(2)MgSi_(2)O_(7) samples are possible contender for single white light generation commercial candidates owing to their strong hypersensitivity of Sm^(3+)ions through host,least possibility for re-absorption of blue-green emission owing to poor direct f-f excitation of Sm^(3+)ions,and high color purity(reddish-orange emission).The prepared powders exhibit excellent electrochemical redox properties and CPE modified optimized powders show outstanding sensitive response which indicates its use in the potential electrochemical sensor materials for drug sensing studies.展开更多
This study presents the photoluminescence characteristic analysis of a series of red phosphors of KAlSiO_(4):1.5 mol%Sm^(3+),x mol%Eu^(3+)(x=2,3,4,5,6,7)prepared via high-temperature solid-phase reaction.The results s...This study presents the photoluminescence characteristic analysis of a series of red phosphors of KAlSiO_(4):1.5 mol%Sm^(3+),x mol%Eu^(3+)(x=2,3,4,5,6,7)prepared via high-temperature solid-phase reaction.The results show that the X-ray diffraction(XRD)refinement results are reliable.The unit cell parameters and volume gradually decrease as the Eu^(3+) concentration increases,resulting in a grain size reduction of 10.22%.When x=6,the emission peaks of Sm^(3+) at 564,601,and 651 nm disappear completely,and the corresponding full width at half maximum becomes 0.At 610 nm,the emission peak intensity of Eu^(3+) is increased by a factor of 4.8.The resonant non-radiative energy transfer effect is greater than the co-excitation effect.A maximum energy transfer efficiency of 97.8%is achieved.The integral area at 610 nm is as high as 85%.The color purity of the phosphor is as high as 92.97%,and the internal quantum yield gradually changes from 32%to 51%.Ultimately,these results confirm that the silicate phosphor is suitable for the red component in the three primary color phosphors of white light-emitting diodes.展开更多
Fluorescent carbon dots(CDs)have recently become a research hotspot in multidisciplinary fields owing to their distinctive advantages,including outstanding photoluminescence properties,high biocompatibility,low toxici...Fluorescent carbon dots(CDs)have recently become a research hotspot in multidisciplinary fields owing to their distinctive advantages,including outstanding photoluminescence properties,high biocompatibility,low toxicity,and abundant raw materials.Among the promising CDs,narrow‐bandwidth emissive CDs with high color purity have emerged as a rising star in recent years because of their significant potential applications in bioimaging,information sensing,and photoelectric displays.In this review,the state-of-the-art advances of narrow-bandwidth emissive CDs are systematically summarized,and the factors influencing the emission bandwidth,preparation methods,and applications of narrow-bandwidth emissive CDs are described in detail.Besides,existing challenges and future perspectives for achieving high-performance narrow-bandwidth emissive CDs are also discussed.This overview paper is expected to generate more interest and promote the rapid development of this significant research area.展开更多
In this work,through a facile method of low-temperature(only 350℃)self-reduction,1D nano-sized M_(2)B_(5)O_(9)CI:Eu^(2+)(M=Sr,Ca)blue phosphors with highly efficient performance can be obtained.The crystal structure,...In this work,through a facile method of low-temperature(only 350℃)self-reduction,1D nano-sized M_(2)B_(5)O_(9)CI:Eu^(2+)(M=Sr,Ca)blue phosphors with highly efficient performance can be obtained.The crystal structure,morphology and photoluminescence(PL)properties including thermal stability of M_(2)B_(5)O_(9)CI:Eu^(2+)(M=Sr,Ca)phosphors were investigated.The M_(2)B_(5)O_(9)CI:Eu^(2+)(M=Sr,Ca)phosphors show broad band excitation spectra and narrow band emission spectra.The photoluminescence quantum yields(PLQY)of M_(2)B_(5)O_(9)CI:Eu^(2+)(M=Sr,Ca)are as high as 98%and 87.2%,respectively.Furthermore,the color purities of M_(2)B_(5)O_(9)CI:Eu^(2+)(M=Sr,Ca)can reach 99.1%and 93.2%,respectively,When heated up to 150℃,the emission intensities of M_(2)B_(5)O_(9)CI:Eu^(2+)(M=Sr,Ca)phosphors can still keep 72.7%and80.0%,respectively.Finally,the above-mentioned phosphors exhibit outstanding performance when manufacturing WLEDs.展开更多
The encapsulation of a rare earth (RE) complex Eu(DBM)(3)phen in modified S1-MCM-41 with 3-aminopropyltriethoxysilane is reported for the first time. The luminescence intensity of the RE complex in the modified Si-MCM...The encapsulation of a rare earth (RE) complex Eu(DBM)(3)phen in modified S1-MCM-41 with 3-aminopropyltriethoxysilane is reported for the first time. The luminescence intensity of the RE complex in the modified Si-MCM-41 is about 9 times as strong as in unmodified Si-MCM-41 and the luminescence of the RE complex in the modified SI-MCM-41 has good color purity.展开更多
Chromaticity characteristics of several fluorescent dyes in cloth were studied in terms of chromaticity diagram. The dominant wavelength and color purity of the samples were calculated and chromaticity diagrams were d...Chromaticity characteristics of several fluorescent dyes in cloth were studied in terms of chromaticity diagram. The dominant wavelength and color purity of the samples were calculated and chromaticity diagrams were drawn to provide countermeasures with which the perceptual color attributes such as hue and saturation are correlated.展开更多
Organic light-emitting diodes(OLEDs)based on multiple resonance-thermallyactivated delayedfluorescence(MR-TADF)have the advantages of high excitonutilization and excellent color purity.However,the large conjugated plan...Organic light-emitting diodes(OLEDs)based on multiple resonance-thermallyactivated delayedfluorescence(MR-TADF)have the advantages of high excitonutilization and excellent color purity.However,the large conjugated planarity of gen-eral MR-TADF emitters makes them easily aggregate in the form ofπ–πstacking,resulting in aggregation-caused quenching(ACQ)and the formation of excimers,which reduce exciton utilization efficiency and color purity.To address these issues,large shielding units can be incorporated to prevent interchromophore interactions,whereas the majority of reported molecules are limited to blue-green light emis-sions.This work proposes a strategy of incorporating steric hindrance groups atdifferent sites of the B/N core to suppress interactions between chromophore,con-tributing to blue MR-TADF emitters with high photo-luminance quantum yields(PLQYs≥95%)and narrow full width at half maximum(FWHM),and importantly,great suppression of the ACQ effect.Therefore,blue OLEDs achieve high externalquantum efficiencies up to 34.3%and high color purity with FWHM of about 27 nmand CIE around(0.12,0.15),even at a high doping concentration of 20 wt%.展开更多
This review focuses on the history and current state of the art optoelectronic applications of quantum dots involving light emission.We focus mainly on three areas of commercial,or potential commercial interest,includ...This review focuses on the history and current state of the art optoelectronic applications of quantum dots involving light emission.We focus mainly on three areas of commercial,or potential commercial interest,including quantum dot light emitting devices(QLEDs,sometimes called QD-LEDs),lasing applications,and quantum computing applications.The main connection between these areas is the development of the science and engineering needed to achieve electrical excitation of the quantum dot in an optoelectronic device in order to achieve emission with characteristics particularly suited to the application in question.Due to the special physics of quantum dots,these materials are particularly well suited for both existing commercial applications,and potentially for future applications,such as single photon sources,spin cubits,or polarized emission.We conclude with an analysis of the future prospects for these exciting materials.Given 30 years of progress since the Nobel Prize winning work on monodisperse samples of QDs,our goal is to highlight the current start of the art,discuss the current issues for each technology,and suggest future goals for the next 30 years for quantum dot research.展开更多
基金Project supported by Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(NRF-2021R1A6A1A03039493)by the Ministry of Science,Information and Communications Technology(ICT)and Future Planning(2022R1A2C1009389)。
文摘We synthesized reddish-orange luminescent La_(10)W_(22)O_(81)(LWO):Sm^(3+)microphosphors by hydrothermalassisted solid-state reaction.X-ray diffraction analysis reveals that all the studied phosphors crystallize in an orthorhombic structure in the Pbcn space group(60),Field emission scanning electron microscopy indicates that the LWO:1.5 mol%Sm^(3+)phosphor displays a smooth-surfaced hexagonal rod-like shape,with a closed shape at both ends,and high-resolution transmission electron microscopy demonstrates a robust crystalline structure.The chemical composition and valence states of the phosphor were investigated using X-ray photoelectron spectroscopy.At 403 nm excitation,LWO:1.5 mol%Sm3+exhibits maximum intensity with the strongest band at 596 nm(^(4)G_(5/2)→^(6)H_(7/2))in the reddish-orange region.The intensity of Sm^(3+)emission decreases beyond 1.5 mol%owing to concentration quenching regulated by dipole-quadrupole interaction between Sm^(3+)ions.The optimized microphosphor LWO:1.5 mol%Sm^(3+)exhibits color coordinates(0.5760,0.4207),which is close to that of the Amber LED-NSPAR 70 BS(0.570,0.420),displaying the highest color purity of 99.2%and correlated color temperature of 1694 K.In addition,both breast cancer cells MCF-7 and normal lung fibroblasts WI-38 were tested for toxicity with the optimized microphosphor.It is found that the LWO:1.5 Sm^(3+)microphosphor is extremely toxic to cancer cells,but not to normal cells.Based on these results,LWO:Sm^(3+)microphosphor can serve as a biomedical candidate for the treatment of cancer,as well as a potential multicolor emitting material for w-LEDs.
基金financial support from the Science and Technology Development Fund,Macao SAR(0006/2021/AKP,0068/2022/A,0034/2022/AGJ)Jiangsu Key Laboratory for Carbon-Based Functional Materials&Devices(ZZ2102)+6 种基金Gusu Innovation and Entrepreneur Leading Talents(ZXL2023185)the Natural Science Foundation of Fujian Province(2021J02001)Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China Project Program(2021ZZ201)Guangdong-Macao Science and Technology Project(2023A0505020010)supported by Suzhou Key Laboratory of Functional Nano&Soft Materials,the Collaborative Innovation Center of Suzhou Nano Science and Technology(NANO-CIC)the 111 Project,Joint International Research Laboratory of Carbon-Based FunctionalMaterials and DevicesShuangQiao Sun acknowledges the support from Macao Young Scholars Program(MYSP,AM2024010).
文摘High-quality quantum dots(QDs)possess superior electroluminescent efficiencies and ultra-narrow emission linewidths are essential for realizing ultra-high definition QD light-emitting diodes(QLEDs).However,the synthesis of such QDs remains challenging.In this study,we present a facile high-temperature successive ion layer adsorption and reaction(HT-SILAR)strategy for the growth of precisely tailored Zn_(1-x)Cd_(x)Se/ZnSe shells,and the consequent production of high-quality,large-particle,alloyed red CdZnSe/Zn_(1-x)Cd_(x)Se/ZnSe/ZnS/CdZnS QDs.The transitional Zn1 xCdxSe/ZnSe shells serve to effectively suppress heavy hole energy level splitting and weaken the exciton-longitudinal optical phonon coupling of QDs,thus facilitating the formation of highly luminescent QDs with a near-unity photoluminescence quantum yield of 97.8%and narrow emission with a full width at half maximum of 17.1 nm.In addition,the introduction of transitional shells can extend the particle size of QDs to 19.0 nm,which is beneficial for efficient carrier recombination and reduced Joule heating in QD-based LEDs.As a result,the fabricated QLEDs can achieve a record external quantum efficiency of 38.2%,luminance over 120,000 cd m^(-2),and exceptional operational stability T95(tested at 1,000 cd m^(-2))of 24,100 h.These findings provide new ave-nues for synthesizing high-quality QDs with high color purity.
基金supported by the National Natural Science Foundation of China(no.21935005)the National Key R&D Program of China(no.2020YFA0714601)Program for JLU Science and Technology Innovative Research Team(no.2019TD-33).
文摘The development and enrichment of organic materials with narrowband emission in longer wavelength regions beyond 515 nm still remains a great challenge.Herein,a synthetic methodology for narrowband emission materials has been proposed to functionalize multiple resonance(MR)skeletons and generate a universal building block,namely,the key intermediate DtCzB-Bpin,which can be utilized to construct multifarious thermally activated delayed fluorescence(TADF)materials with high color purity through a simple one-step Suzuki coupling reaction.Based on this unique synthetic strategy,a series of efficient narrowband green TADF emitters has been constructed by localized attachment of 1,3,5-triazine and pyrimidine derivatives-based acceptors onto B–N-containing MR frameworks with 1,3-bis(3,6-di-tertbutylcarbazol-9-yl)benzene(DtCz)as the ligand.The precise modulation of the acceptor is an intelligent approach to achieve bathochromic shift and narrowband emission simultaneously.The DtCzB-TPTRZbased organic light-emitting diode(OLED)exhibits pure green emission with Commission Internationale de L’Eclairage(CIE)coordinates of(0.23,0.68),a maximum external quantum efficiency(EQE)of 30.6%,and relatively low efficiency roll-off.
文摘A series of orange-red light emitting Ca_(2)MgSi_(2)O_(7):Sm^(3+)nanopowders were fabricated via low-cost ecofriendly green combustion technique using Aloe vera gel as fuel.The phase purity of the samples were confirmed by the powder X-ray diffraction(PXRD)technique.Pure single-phase tetragonal structure is observed from the PXRD results with no additional impurity peaks.The band gap energy of the fabricated powders was estimated by diffuse reflectance spectra(DRS)and is found to be in the range of 4.01-5.98 eV.A high resolution scanning electron microscope(SEM)was used to study the morphological behaviour of the samples.Honeycomb-like structures are observed from the SEM results.The particle size was evaluated by transmission electron microscopy(TEM)and is found to be~50 nm.The interplanar distance is found to be 0.53 nm.Photoluminescence properties were systematically studied in detail.The phosphors are successfully excited at 403 nm NUV light,producing reddish-orange characteristic emission.The emission peaks are centered at 558(^(4)G_(5/2)→^(6)H_(5/2)),607(^(4)G_(5/2)→^(6)H_(7/2))and 645 nm(^(4)G_(5/2)→^(6)H_(9/2)),respectively.Among the observed peaks the red emanation(^(4)G_(5/2)→^(6)H_(7/2))is stronger than the orange emission(^(4)G_(5/2)→^(6)H_(5/2))in the current investigation.The photoluminescent concentration quenching is noticed above 5 mol%Sm^(3+)ion doping content.The dipole-dipole interaction resulting in cross relaxation is found to be the principal cause of concentration quenching mechanism.The color features such as Commission Internationale de I’Eclairage(CIE)and correlated color temperature(CCT)were studied in detail.The optimized chromaticity coordinates were estimated to be(0.6363,0.3632),which fall in the reddish-orange region.The average CCT value obtained is 3362 K.The average color purity is found to be~82%.Sm^(3+)incorporated Ca_(2)MgSi_(2)O_(7) samples are possible contender for single white light generation commercial candidates owing to their strong hypersensitivity of Sm^(3+)ions through host,least possibility for re-absorption of blue-green emission owing to poor direct f-f excitation of Sm^(3+)ions,and high color purity(reddish-orange emission).The prepared powders exhibit excellent electrochemical redox properties and CPE modified optimized powders show outstanding sensitive response which indicates its use in the potential electrochemical sensor materials for drug sensing studies.
基金Project supported by the Scientific Research Projects of Universities in Xinjiang Autonomous Region(XJEDU2017I009)the Scientific Research and Innovation Project of Postgraduates in Xinjiang Autonomous Region(XJ2020G233)。
文摘This study presents the photoluminescence characteristic analysis of a series of red phosphors of KAlSiO_(4):1.5 mol%Sm^(3+),x mol%Eu^(3+)(x=2,3,4,5,6,7)prepared via high-temperature solid-phase reaction.The results show that the X-ray diffraction(XRD)refinement results are reliable.The unit cell parameters and volume gradually decrease as the Eu^(3+) concentration increases,resulting in a grain size reduction of 10.22%.When x=6,the emission peaks of Sm^(3+) at 564,601,and 651 nm disappear completely,and the corresponding full width at half maximum becomes 0.At 610 nm,the emission peak intensity of Eu^(3+) is increased by a factor of 4.8.The resonant non-radiative energy transfer effect is greater than the co-excitation effect.A maximum energy transfer efficiency of 97.8%is achieved.The integral area at 610 nm is as high as 85%.The color purity of the phosphor is as high as 92.97%,and the internal quantum yield gradually changes from 32%to 51%.Ultimately,these results confirm that the silicate phosphor is suitable for the red component in the three primary color phosphors of white light-emitting diodes.
基金This study was supported by the National Key Research and Development Program of China(2019YFE0112200)the Science and Technology Development Fund of Macao SAR,China(0073/2019/AMJ)+2 种基金the National Natural Science Foundation of China(51873007,21835006,51961165102,and 52003022)the Fundamental Research Funds for the Central Universities of China(PT2021-02,buctrc202009)the high-performance computing platform of BUCT.
文摘Fluorescent carbon dots(CDs)have recently become a research hotspot in multidisciplinary fields owing to their distinctive advantages,including outstanding photoluminescence properties,high biocompatibility,low toxicity,and abundant raw materials.Among the promising CDs,narrow‐bandwidth emissive CDs with high color purity have emerged as a rising star in recent years because of their significant potential applications in bioimaging,information sensing,and photoelectric displays.In this review,the state-of-the-art advances of narrow-bandwidth emissive CDs are systematically summarized,and the factors influencing the emission bandwidth,preparation methods,and applications of narrow-bandwidth emissive CDs are described in detail.Besides,existing challenges and future perspectives for achieving high-performance narrow-bandwidth emissive CDs are also discussed.This overview paper is expected to generate more interest and promote the rapid development of this significant research area.
基金Project supported by the National Natural Science Foundation of China(22003035,22073061)the Natural Science Foundation of Shaanxi Province Department of Education(21JK0587)+2 种基金the Natural Science Foundation of Shaanxi Province(2020GY-237)the Foundation of Shaanxi Xueqian Normal University(2020YBKJ70)Innovation and Entrepreneurship Training Program for College Students in Shaanxi Province(S202014390037)。
文摘In this work,through a facile method of low-temperature(only 350℃)self-reduction,1D nano-sized M_(2)B_(5)O_(9)CI:Eu^(2+)(M=Sr,Ca)blue phosphors with highly efficient performance can be obtained.The crystal structure,morphology and photoluminescence(PL)properties including thermal stability of M_(2)B_(5)O_(9)CI:Eu^(2+)(M=Sr,Ca)phosphors were investigated.The M_(2)B_(5)O_(9)CI:Eu^(2+)(M=Sr,Ca)phosphors show broad band excitation spectra and narrow band emission spectra.The photoluminescence quantum yields(PLQY)of M_(2)B_(5)O_(9)CI:Eu^(2+)(M=Sr,Ca)are as high as 98%and 87.2%,respectively.Furthermore,the color purities of M_(2)B_(5)O_(9)CI:Eu^(2+)(M=Sr,Ca)can reach 99.1%and 93.2%,respectively,When heated up to 150℃,the emission intensities of M_(2)B_(5)O_(9)CI:Eu^(2+)(M=Sr,Ca)phosphors can still keep 72.7%and80.0%,respectively.Finally,the above-mentioned phosphors exhibit outstanding performance when manufacturing WLEDs.
基金We are grateful to the National Natural Science Foundation of ChinaNational Key Project for Fundamental Research, the Natio
文摘The encapsulation of a rare earth (RE) complex Eu(DBM)(3)phen in modified S1-MCM-41 with 3-aminopropyltriethoxysilane is reported for the first time. The luminescence intensity of the RE complex in the modified Si-MCM-41 is about 9 times as strong as in unmodified Si-MCM-41 and the luminescence of the RE complex in the modified SI-MCM-41 has good color purity.
文摘Chromaticity characteristics of several fluorescent dyes in cloth were studied in terms of chromaticity diagram. The dominant wavelength and color purity of the samples were calculated and chromaticity diagrams were drawn to provide countermeasures with which the perceptual color attributes such as hue and saturation are correlated.
基金National Natural Science Foundation of China,Grant/Award Numbers:51733010,52073316Basic and Applied Basic Research Foundation of Guangdong Province,Grant/Award Numbers:2022B1515020052,2021A1515110119。
文摘Organic light-emitting diodes(OLEDs)based on multiple resonance-thermallyactivated delayedfluorescence(MR-TADF)have the advantages of high excitonutilization and excellent color purity.However,the large conjugated planarity of gen-eral MR-TADF emitters makes them easily aggregate in the form ofπ–πstacking,resulting in aggregation-caused quenching(ACQ)and the formation of excimers,which reduce exciton utilization efficiency and color purity.To address these issues,large shielding units can be incorporated to prevent interchromophore interactions,whereas the majority of reported molecules are limited to blue-green light emis-sions.This work proposes a strategy of incorporating steric hindrance groups atdifferent sites of the B/N core to suppress interactions between chromophore,con-tributing to blue MR-TADF emitters with high photo-luminance quantum yields(PLQYs≥95%)and narrow full width at half maximum(FWHM),and importantly,great suppression of the ACQ effect.Therefore,blue OLEDs achieve high externalquantum efficiencies up to 34.3%and high color purity with FWHM of about 27 nmand CIE around(0.12,0.15),even at a high doping concentration of 20 wt%.
文摘This review focuses on the history and current state of the art optoelectronic applications of quantum dots involving light emission.We focus mainly on three areas of commercial,or potential commercial interest,including quantum dot light emitting devices(QLEDs,sometimes called QD-LEDs),lasing applications,and quantum computing applications.The main connection between these areas is the development of the science and engineering needed to achieve electrical excitation of the quantum dot in an optoelectronic device in order to achieve emission with characteristics particularly suited to the application in question.Due to the special physics of quantum dots,these materials are particularly well suited for both existing commercial applications,and potentially for future applications,such as single photon sources,spin cubits,or polarized emission.We conclude with an analysis of the future prospects for these exciting materials.Given 30 years of progress since the Nobel Prize winning work on monodisperse samples of QDs,our goal is to highlight the current start of the art,discuss the current issues for each technology,and suggest future goals for the next 30 years for quantum dot research.
