The research of purely organic materials with long afterglow has drawn more and more attention,especially for those with stimulus‐response characteristic.So far,this kind of material is really very scarce and their p...The research of purely organic materials with long afterglow has drawn more and more attention,especially for those with stimulus‐response characteristic.So far,this kind of material is really very scarce and their performance is not good enough.In this study,we successfully developed an efficient heatingresponsive room‐temperature phosphorescence material with phosphorescence efficiency and lifetime up to 13.4%and 2.08 s through the simple host–guest doping strategy.Further on,by introducing the additional energy acceptor of fluorescein with concentration‐dependent emission to construct ternary doping systems,the afterglow color was extended from blue to yellow.Accordingly,the multicolor thermal printings have been easily realized,showing the great practical application prospects.展开更多
Investigation on the bright and stable upconversion(UC)phosphors with multicolor emissions is fundamental and significant for the frontier applications of display and tempe rature probe.He re,dive rse emitting colors ...Investigation on the bright and stable upconversion(UC)phosphors with multicolor emissions is fundamental and significant for the frontier applications of display and tempe rature probe.He re,dive rse emitting colors with blue,cyan and yellowish green,which are caused by the energy transfer and crossrelaxation processes,are obtained by altering Er^3+,Tm^3+and Yb^3+concentrations in Er3+singly,Er^3+-Tm^3+-Yb^3+co-and tri-doped double perovskite La2ZnTiO6(LZT)phosphors synthesized by a simple solid-state reaction.In addition,excellent infrared emission at 801 nm located at"first biological windo w"is collected in Tm^3+-Yb^3+co-doped phosphors.Meanwhile,the temperature sensing properties based on the thermally coupled levels((^2H11/2)/(^4S3/2))of Er3+ions were analyzed from 298 to 573 K of LZT:0.15 Er^3+/0.10 Yb^3+phosphor,demonstrating that the maximal sensitivity value is about56×10^-4 K^-1 at 448 K.All these results imply that this kind of UC material has potential applications in display,bioimaging and optical device.展开更多
Mechanoluminescence has attracted increasing attentions because it can convert the kinetic energy during human daily motions into light to be used in sensors and displays. However, its practical applications are still...Mechanoluminescence has attracted increasing attentions because it can convert the kinetic energy during human daily motions into light to be used in sensors and displays. However, its practical applications are still hindered by the weak brightness and limited color while under large forces. Herein, we developed novel piezoluminescent devices(PLDs) which could effectively emit visible light under low pressing forces through the stress-concentration and enhancing deformation on the basis of carefully-designed array structures. The emitting colors were also tunable by using bilayer luminescent film under different pressures. This work not only provides a new strategy to effectively harvest mechanical energy into light,but also presents a scalable, low-cost and color-tunable PLD which shows great potentials in various applications such as luminescent floors, shoes and stress-activated displays.展开更多
Color-tunable phosphors Sr0.94MoO4：xEu^3＋, （0.06 - x）Tb^3＋ were synthesized rapidly by microwave ra- diation method with active carbon particle as microwave absorbent. The synthesized phosphors were investigated ...Color-tunable phosphors Sr0.94MoO4：xEu^3＋, （0.06 - x）Tb^3＋ were synthesized rapidly by microwave ra- diation method with active carbon particle as microwave absorbent. The synthesized phosphors were investigated by X-ray powder diffraction （XRD） and fluorescence spec- trophotometer. The effects of the ratio of Eu^3＋ and Tb^3＋ on the phase structure and luminescent properties of the phos- phors were discussed. The results show that Eu^3＋,Tb^3＋-doped samples can be well indexed to the pure tetragonal scheelite- type SrMoO4, indicating that Eu^3＋ and Tb^3＋ are effectively doped into the SrMoO4 host lattices. The as-synthesized Sro.94MoO4：xEu^3＋,（0.06 - x）Tb^3＋ phosphors have two luminescent centers （Eu^3＋ and Tb^3＋）, which can show red and green emissions under ultraviolet light excitation, respec- tively. Doping concentration of Eu^3＋ and Tb^3＋ has great effect on the intensity of emission peaks and the chromaticity of the samples, and the full color between green and red light can be achieved by adjusting the relative concentration of Eu^3＋ and Tb^3＋.展开更多
The color-tunable white organic light-emitting diode (CT-WOLED) with wide correlation color temperature (CCT) has many advantages in optimizing the artificial light source to adapt to the human physiological cycle. Th...The color-tunable white organic light-emitting diode (CT-WOLED) with wide correlation color temperature (CCT) has many advantages in optimizing the artificial light source to adapt to the human physiological cycle. The research on the change trend of CCT and the law of extending the change range of CCT will help to further improve the performance of this kind of device. The present work fabricated a series of CT-WOLED devices with a simple structure, which are all composed of two ultra-thin phosphor layers (PO-01 and Flrpic) and a spacer interlayer. The yellow interface exciplex (TCTA/PO-T2T) formed between the spacer layer (PO-T2T) and transmission material (TCTA) in EML will decrease the CCT value at low voltage. The relationship between the energy transfer in EML and CCT change trend is investigated by adjusting the interface exciplexes and the thickness of the interlayer or the phosphor layer in devices A, B and C, respectively. The results demonstrate that a simple OLED device with an interlayer inserted between two ultra-thin phosphor layers can achieve a wider CCT span from 3359 K to 6451 K at voltage increases from 2.75 V to 8.25 V. .展开更多
Chiral B,N-doped polycyclic aromatic hydrocarbons with circularly polarized luminescence(CPL) and small full-width at halfmaxima(FWHM) are promising multiple resonance(MR) emitters for CP organic light-emitting diodes...Chiral B,N-doped polycyclic aromatic hydrocarbons with circularly polarized luminescence(CPL) and small full-width at halfmaxima(FWHM) are promising multiple resonance(MR) emitters for CP organic light-emitting diodes(CP-OLEDs).This work presents a pair of chiral MR enantiomers,P/M-o[B-N]_(2)N_(2),featuring B–N bonds incorporated within a[7]-helicene skeleton.These enantiomers exhibit narrow 0-0 and 0-1 electronic transition bands,whose relative intensity can be fine-tuned by increasing doping concentrations,resulting in redshifts of the emission peak from 542 to 592 nm.The enantiomers show mirrorsymmetric CPL spectra with an asymmetry factor(|g_(PL)|) of 1.0×10^(-3).The hyperfluorescent CP-OLEDs with double-sensitized emitting layers display a FWHM of 33 nm,an external quantum efficiency of 25.1%,and a|g_(EL)|factor of 7.7×10^(-4).Notably,the CP-OLEDs realize color-tunable CP electroluminescence peak from 553 to 613 nm by regulating the vibrational coupling.This work provides a novel concept for the design of helical CP-MR materials and CP-OLEDs,highlighting their potential for future applications in advanced optoelectronic devices.展开更多
Seeking pure organic functional luminescent materials that are processed from green, low-cost, and sustainable resources remains a challenging but beneficial task. As an abundant natural polymer composed of crosslinke...Seeking pure organic functional luminescent materials that are processed from green, low-cost, and sustainable resources remains a challenging but beneficial task. As an abundant natural polymer composed of crosslinked phenol ether units, lignin is a potential source of organic luminescent material because of the presence of extensive aromatic fragments. In the present work, a remarkable afterglow involving room-temperature phosphorescence(RTP) was achieved via simply embedding alkalized lignin into polyvinyl alcohol(PVA) matrix, and an ultralong luminescence lifetime of more than 160 ms was observed. More importantly, our study revealed that small fragments of hydrolyzed lignin(named LA-H) bearing extensive phenolic oxygen anions were the effective luminescent species. When embedded into a PVA matrix, LA-H showed remarkably high luminescence quantum yield and long lifetime of RTP emission compared with those of unprocessed lignin. Additionally, the various phenol oxygen anion moieties endowed LA-H with an excitation-dependent characteristic: the color-tunable RTP could be simply tuned from a maximum emission wavelength of 434–532 nm via altering the excitation wavelength. Thus, the color-tunable afterglow of emissive LA-H could be facilely obtained with a yield up to 38.4% using simple acid hydrolysis of lignin without other complex synthesis procedures. This work opens new avenues in the large-scale preparation of low-cost and sustainable pure organic RTP materials.展开更多
Using a color-tunable organic light-emitting diode (CT-OLED) can accord with the circadian cycle of humans and realize healthy lighting. The variation range of the correlated color temperature (CCT) is an important pa...Using a color-tunable organic light-emitting diode (CT-OLED) can accord with the circadian cycle of humans and realize healthy lighting. The variation range of the correlated color temperature (CCT) is an important parameter to measure the performance of CT-OLEDs. In this paper, the effect of changing the utilization of phosphorescent materials and the position of the recombination zone (RZ) in the device are investigated by changing the thickness of the emissive layer (EML) and the doping ratio of the host and guest materials. The results show that reducing the red phosphorescent material and improving the blue phosphorescent material can affect the change direction of CCT, but it is not enough to expand the span of CCT (ΔCCT). It is more conducive to improving ΔCCT by more reasonable regulation of the position of the main RZ in EML and the energy transfer from the blue sub-EML to the red sub-EML. Device D obtains the best electro-optic and spectral characteristics, in which the maximum ΔCCT is 5746 K (2661 - 8407 K) as the voltage changes from 3.75 V to 9.75 V, the maximum current efficiency and luminance reach 18.34 cd·A<sup>-1</sup> and 12,100 cd·m<sup>-2</sup>, respectively.展开更多
A novel series of color-tunable single-phased phosphors La1-x-yPO4：xEu3＋/yTb3＋（x=0, 0.01, 0.02, 0.03, 0.04, 0.05; y=0, 0.05, 0.10, 0.15, 0.20） was synthesized via microwave-assisted co-precipitation method with d...A novel series of color-tunable single-phased phosphors La1-x-yPO4：xEu3＋/yTb3＋（x=0, 0.01, 0.02, 0.03, 0.04, 0.05; y=0, 0.05, 0.10, 0.15, 0.20） was synthesized via microwave-assisted co-precipitation method with diammonium hydrogen phosphate as precipitant. The morphology, crystal structure and photoluminescence properties of the as-prepared samples were characterized by means of X-ray diffraction（XRD）, scanning electron microscopy（SEM） and fluorescence spectrophotometer. The results reveal that the as-synthesized samples calcined at 1100 ℃ display spherical morphology with uniform distribution. Upon excitation with 350 nm ultraviolet radiation, the LaPOa：Eu3＋/Tb3＋ phosphors showed a green light peaking at 543 nm assigned to the characteristic 5Da-7F5 emission of Tb3＋ and a red light peaking at 591 nm corresponding to the characteristic 5D0-7F1 emission of Eu3＋ simultaneously. For the Eu3＋/Tb3＋ co-activated phosphors, Tb3＋ acts as an efficient sensitizer to enhance the emission intensity of Eu3＋ ions. The energy transfer mechanism and the emission color tunability of LaPO4：Eu3＋/Tb3＋ have been studied. The results indicate that a color-tunable luminescence（from green to white to red） can be achieved by adjusting the Eu3＋/Tb3＋ doping ratio in the LaPO4 host matrix.展开更多
A series of color-tunable KLaSiO4：Ce3＋,Mn2＋phosphors were successfully prepared and the luminescent properties were investigated. Upon excitation at 290 nm, the emission spectra of KLaSiO4：Ce3＋,Mn2＋phosphors inc...A series of color-tunable KLaSiO4：Ce3＋,Mn2＋phosphors were successfully prepared and the luminescent properties were investigated. Upon excitation at 290 nm, the emission spectra of KLaSiO4：Ce3＋,Mn2＋phosphors included a blue emission band and a red emission band. Increasing the doping concentration of Mn2＋ions, the red emission was strengthened considerably, and the blue emission of Ce3＋ was reduced, owing to the efficient energy transfer. The composition optimized KLa0.96SiO4：0.02Ce3＋,0.02Mn2＋sample exhibited the white light emission brightly with the chromaticity coordinates of （0.331, 0.337）. Therefore, KLaSiO4：Ce3＋, Mn2＋could be used as a white phosphor candidate for white light-emitting diodes devices.展开更多
An efficient color-tunable hybrid white organic light-emitting diode is demonstrated with double interlayers of 2,7-bis(carbazol-9-yl)-9,9-ditoylfluo- rene/2-(diphenylphosphoryl) spiroflu-orene (DMFL-CBP/SPPO1) insert...An efficient color-tunable hybrid white organic light-emitting diode is demonstrated with double interlayers of 2,7-bis(carbazol-9-yl)-9,9-ditoylfluo- rene/2-(diphenylphosphoryl) spiroflu-orene (DMFL-CBP/SPPO1) inserted between blue fluorescent and yellow phosphorescent-emitting layers, and exhibits Commission Internationale de l’Eclairage (CIE1931) ranging from warm white (0.4368, 0.4497) to cool white (0.2781, 0.2896) with driving current density from 0.2 to 40 mA/cm2. The recombination of singlet and the triplet excitons in blue fluores-cent-emitting layer and yellow phosphorescent-emitting layer, respectively, can be modulated by both the thickness of these double interlayers and the applied current densities.展开更多
Nonconjugated polymer dots(PDs)without largely conjugated structures entitle their advantages such as environment friendliness,nontoxicity,and intrinsic fluorescence.However,color-tunable PDs remain a challenge.Herein...Nonconjugated polymer dots(PDs)without largely conjugated structures entitle their advantages such as environment friendliness,nontoxicity,and intrinsic fluorescence.However,color-tunable PDs remain a challenge.Herein,polyvinyl pyrrolidone(PVP)and ascorbic acid(AA)are used to synthesize nonconjugated PDs,namely,PA PDs with intensive blue emission.The introduction of a third component,m-phenylenediamine(MPD),redshifted the emission to green.The asprepared color-tunable blue to green emissive PDs exhibit excellent properties,whether in solution or in solid state,originated from the mechanism of clusteringtriggered emission(CTE)induced by the overlap of electron-rich atoms,the strong inter/intrachain interaction.The quantum yields of blue and green PDs reached up to 15.07%and 28.22%,respectively.Furthermore,PA PDs were successfully applied to the highly efficient photocatalytic degradation for dyes:methylene blue(MB)and methyl orange(MO)were degraded by 89.9%and 93.8%within 20 min under visible light,respectively.展开更多
基金National Natural Science Foundation of China,Grant/Award Number:51903188Natural Science Foundation of Tianjin City,Grant/Award Number:19JCQNJC04500The starting Grants of Tianjin University and Tianjin Government。
文摘The research of purely organic materials with long afterglow has drawn more and more attention,especially for those with stimulus‐response characteristic.So far,this kind of material is really very scarce and their performance is not good enough.In this study,we successfully developed an efficient heatingresponsive room‐temperature phosphorescence material with phosphorescence efficiency and lifetime up to 13.4%and 2.08 s through the simple host–guest doping strategy.Further on,by introducing the additional energy acceptor of fluorescein with concentration‐dependent emission to construct ternary doping systems,the afterglow color was extended from blue to yellow.Accordingly,the multicolor thermal printings have been easily realized,showing the great practical application prospects.
基金supported by the National Natural Science Foundation of China(11464017,11864015)the Scientific Research Foundation for Universities from the Education Bureau of Jiangxi Province(GJJ170490)+1 种基金Foundation of Natural Science Funds for Distinguished Young Scholar of Jiangxi Province(20171BCB23064)the Science and Technology Major Project of Jiangxi Province(20165ABC28010).
文摘Investigation on the bright and stable upconversion(UC)phosphors with multicolor emissions is fundamental and significant for the frontier applications of display and tempe rature probe.He re,dive rse emitting colors with blue,cyan and yellowish green,which are caused by the energy transfer and crossrelaxation processes,are obtained by altering Er^3+,Tm^3+and Yb^3+concentrations in Er3+singly,Er^3+-Tm^3+-Yb^3+co-and tri-doped double perovskite La2ZnTiO6(LZT)phosphors synthesized by a simple solid-state reaction.In addition,excellent infrared emission at 801 nm located at"first biological windo w"is collected in Tm^3+-Yb^3+co-doped phosphors.Meanwhile,the temperature sensing properties based on the thermally coupled levels((^2H11/2)/(^4S3/2))of Er3+ions were analyzed from 298 to 573 K of LZT:0.15 Er^3+/0.10 Yb^3+phosphor,demonstrating that the maximal sensitivity value is about56×10^-4 K^-1 at 448 K.All these results imply that this kind of UC material has potential applications in display,bioimaging and optical device.
基金supported by the National Key R&D Program of China (2016YFA0203302)the National Natural Science Foundation of China (21634003, 51573027, 51673043, 21604012, 21805044, 21875042, 11602058, and 11872150)+3 种基金Shanghai Science and Technology Committee (16JC1400702, 17QA1400400, 18QA1400700, and 18QA1400800)Shanghai Municipal Education Commission (2017-01-07-00-07-E00062)Shanghai Chenguang Program (16CG01)Yanchang Petroleum Group
文摘Mechanoluminescence has attracted increasing attentions because it can convert the kinetic energy during human daily motions into light to be used in sensors and displays. However, its practical applications are still hindered by the weak brightness and limited color while under large forces. Herein, we developed novel piezoluminescent devices(PLDs) which could effectively emit visible light under low pressing forces through the stress-concentration and enhancing deformation on the basis of carefully-designed array structures. The emitting colors were also tunable by using bilayer luminescent film under different pressures. This work not only provides a new strategy to effectively harvest mechanical energy into light,but also presents a scalable, low-cost and color-tunable PLD which shows great potentials in various applications such as luminescent floors, shoes and stress-activated displays.
基金financially supported by the National Natural Science Foundation of China (No.21301046)
文摘Color-tunable phosphors Sr0.94MoO4：xEu^3＋, （0.06 - x）Tb^3＋ were synthesized rapidly by microwave ra- diation method with active carbon particle as microwave absorbent. The synthesized phosphors were investigated by X-ray powder diffraction （XRD） and fluorescence spec- trophotometer. The effects of the ratio of Eu^3＋ and Tb^3＋ on the phase structure and luminescent properties of the phos- phors were discussed. The results show that Eu^3＋,Tb^3＋-doped samples can be well indexed to the pure tetragonal scheelite- type SrMoO4, indicating that Eu^3＋ and Tb^3＋ are effectively doped into the SrMoO4 host lattices. The as-synthesized Sro.94MoO4：xEu^3＋,（0.06 - x）Tb^3＋ phosphors have two luminescent centers （Eu^3＋ and Tb^3＋）, which can show red and green emissions under ultraviolet light excitation, respec- tively. Doping concentration of Eu^3＋ and Tb^3＋ has great effect on the intensity of emission peaks and the chromaticity of the samples, and the full color between green and red light can be achieved by adjusting the relative concentration of Eu^3＋ and Tb^3＋.
文摘The color-tunable white organic light-emitting diode (CT-WOLED) with wide correlation color temperature (CCT) has many advantages in optimizing the artificial light source to adapt to the human physiological cycle. The research on the change trend of CCT and the law of extending the change range of CCT will help to further improve the performance of this kind of device. The present work fabricated a series of CT-WOLED devices with a simple structure, which are all composed of two ultra-thin phosphor layers (PO-01 and Flrpic) and a spacer interlayer. The yellow interface exciplex (TCTA/PO-T2T) formed between the spacer layer (PO-T2T) and transmission material (TCTA) in EML will decrease the CCT value at low voltage. The relationship between the energy transfer in EML and CCT change trend is investigated by adjusting the interface exciplexes and the thickness of the interlayer or the phosphor layer in devices A, B and C, respectively. The results demonstrate that a simple OLED device with an interlayer inserted between two ultra-thin phosphor layers can achieve a wider CCT span from 3359 K to 6451 K at voltage increases from 2.75 V to 8.25 V. .
基金supported by the National Natural Science Foundation of China (92256304, 21975119)the China Post-doctoral Science Foundation (2022M710020)。
文摘Chiral B,N-doped polycyclic aromatic hydrocarbons with circularly polarized luminescence(CPL) and small full-width at halfmaxima(FWHM) are promising multiple resonance(MR) emitters for CP organic light-emitting diodes(CP-OLEDs).This work presents a pair of chiral MR enantiomers,P/M-o[B-N]_(2)N_(2),featuring B–N bonds incorporated within a[7]-helicene skeleton.These enantiomers exhibit narrow 0-0 and 0-1 electronic transition bands,whose relative intensity can be fine-tuned by increasing doping concentrations,resulting in redshifts of the emission peak from 542 to 592 nm.The enantiomers show mirrorsymmetric CPL spectra with an asymmetry factor(|g_(PL)|) of 1.0×10^(-3).The hyperfluorescent CP-OLEDs with double-sensitized emitting layers display a FWHM of 33 nm,an external quantum efficiency of 25.1%,and a|g_(EL)|factor of 7.7×10^(-4).Notably,the CP-OLEDs realize color-tunable CP electroluminescence peak from 553 to 613 nm by regulating the vibrational coupling.This work provides a novel concept for the design of helical CP-MR materials and CP-OLEDs,highlighting their potential for future applications in advanced optoelectronic devices.
基金supported by the National Natural Science Foundation of China (21788102, 22125803, 22020102006,21871083, 22101083)Shanghai Municipal Science and Technology Major Project (2018SHZDZX03)+3 种基金‘Shu Guang’ Project supported by Shanghai Municipal Education Commission and Shanghai Education Development Foundation (19SG26)the Innovation Program of Shanghai Municipal Education Commission (2017-01-07-00-02 E00010)the Fundamental Research Funds for the Central Universitiesthe China Postdoctoral Science Foundation (2021M691009)。
文摘Seeking pure organic functional luminescent materials that are processed from green, low-cost, and sustainable resources remains a challenging but beneficial task. As an abundant natural polymer composed of crosslinked phenol ether units, lignin is a potential source of organic luminescent material because of the presence of extensive aromatic fragments. In the present work, a remarkable afterglow involving room-temperature phosphorescence(RTP) was achieved via simply embedding alkalized lignin into polyvinyl alcohol(PVA) matrix, and an ultralong luminescence lifetime of more than 160 ms was observed. More importantly, our study revealed that small fragments of hydrolyzed lignin(named LA-H) bearing extensive phenolic oxygen anions were the effective luminescent species. When embedded into a PVA matrix, LA-H showed remarkably high luminescence quantum yield and long lifetime of RTP emission compared with those of unprocessed lignin. Additionally, the various phenol oxygen anion moieties endowed LA-H with an excitation-dependent characteristic: the color-tunable RTP could be simply tuned from a maximum emission wavelength of 434–532 nm via altering the excitation wavelength. Thus, the color-tunable afterglow of emissive LA-H could be facilely obtained with a yield up to 38.4% using simple acid hydrolysis of lignin without other complex synthesis procedures. This work opens new avenues in the large-scale preparation of low-cost and sustainable pure organic RTP materials.
文摘Using a color-tunable organic light-emitting diode (CT-OLED) can accord with the circadian cycle of humans and realize healthy lighting. The variation range of the correlated color temperature (CCT) is an important parameter to measure the performance of CT-OLEDs. In this paper, the effect of changing the utilization of phosphorescent materials and the position of the recombination zone (RZ) in the device are investigated by changing the thickness of the emissive layer (EML) and the doping ratio of the host and guest materials. The results show that reducing the red phosphorescent material and improving the blue phosphorescent material can affect the change direction of CCT, but it is not enough to expand the span of CCT (ΔCCT). It is more conducive to improving ΔCCT by more reasonable regulation of the position of the main RZ in EML and the energy transfer from the blue sub-EML to the red sub-EML. Device D obtains the best electro-optic and spectral characteristics, in which the maximum ΔCCT is 5746 K (2661 - 8407 K) as the voltage changes from 3.75 V to 9.75 V, the maximum current efficiency and luminance reach 18.34 cd·A<sup>-1</sup> and 12,100 cd·m<sup>-2</sup>, respectively.
基金Supported by the National Natural Science Foundation of China（No.50772016）.
文摘A novel series of color-tunable single-phased phosphors La1-x-yPO4：xEu3＋/yTb3＋（x=0, 0.01, 0.02, 0.03, 0.04, 0.05; y=0, 0.05, 0.10, 0.15, 0.20） was synthesized via microwave-assisted co-precipitation method with diammonium hydrogen phosphate as precipitant. The morphology, crystal structure and photoluminescence properties of the as-prepared samples were characterized by means of X-ray diffraction（XRD）, scanning electron microscopy（SEM） and fluorescence spectrophotometer. The results reveal that the as-synthesized samples calcined at 1100 ℃ display spherical morphology with uniform distribution. Upon excitation with 350 nm ultraviolet radiation, the LaPOa：Eu3＋/Tb3＋ phosphors showed a green light peaking at 543 nm assigned to the characteristic 5Da-7F5 emission of Tb3＋ and a red light peaking at 591 nm corresponding to the characteristic 5D0-7F1 emission of Eu3＋ simultaneously. For the Eu3＋/Tb3＋ co-activated phosphors, Tb3＋ acts as an efficient sensitizer to enhance the emission intensity of Eu3＋ ions. The energy transfer mechanism and the emission color tunability of LaPO4：Eu3＋/Tb3＋ have been studied. The results indicate that a color-tunable luminescence（from green to white to red） can be achieved by adjusting the Eu3＋/Tb3＋ doping ratio in the LaPO4 host matrix.
基金Project supported by the Gansu Industry and Information Technology Committee(773000054000001)the Fundamental Research Funds for the Central Universities(lzujbky-2014-37)+1 种基金Specialized Reserch Fund for the Doctoral Program of Higher Education(20120211130003)the National Natural Science Foundation of China(51372105)
文摘A series of color-tunable KLaSiO4：Ce3＋,Mn2＋phosphors were successfully prepared and the luminescent properties were investigated. Upon excitation at 290 nm, the emission spectra of KLaSiO4：Ce3＋,Mn2＋phosphors included a blue emission band and a red emission band. Increasing the doping concentration of Mn2＋ions, the red emission was strengthened considerably, and the blue emission of Ce3＋ was reduced, owing to the efficient energy transfer. The composition optimized KLa0.96SiO4：0.02Ce3＋,0.02Mn2＋sample exhibited the white light emission brightly with the chromaticity coordinates of （0.331, 0.337）. Therefore, KLaSiO4：Ce3＋, Mn2＋could be used as a white phosphor candidate for white light-emitting diodes devices.
文摘An efficient color-tunable hybrid white organic light-emitting diode is demonstrated with double interlayers of 2,7-bis(carbazol-9-yl)-9,9-ditoylfluo- rene/2-(diphenylphosphoryl) spiroflu-orene (DMFL-CBP/SPPO1) inserted between blue fluorescent and yellow phosphorescent-emitting layers, and exhibits Commission Internationale de l’Eclairage (CIE1931) ranging from warm white (0.4368, 0.4497) to cool white (0.2781, 0.2896) with driving current density from 0.2 to 40 mA/cm2. The recombination of singlet and the triplet excitons in blue fluores-cent-emitting layer and yellow phosphorescent-emitting layer, respectively, can be modulated by both the thickness of these double interlayers and the applied current densities.
基金Fundamental Scientific Research Business Expenses of Central Universities,Grant/Award Number:2342021DUT21ZD211。
文摘Nonconjugated polymer dots(PDs)without largely conjugated structures entitle their advantages such as environment friendliness,nontoxicity,and intrinsic fluorescence.However,color-tunable PDs remain a challenge.Herein,polyvinyl pyrrolidone(PVP)and ascorbic acid(AA)are used to synthesize nonconjugated PDs,namely,PA PDs with intensive blue emission.The introduction of a third component,m-phenylenediamine(MPD),redshifted the emission to green.The asprepared color-tunable blue to green emissive PDs exhibit excellent properties,whether in solution or in solid state,originated from the mechanism of clusteringtriggered emission(CTE)induced by the overlap of electron-rich atoms,the strong inter/intrachain interaction.The quantum yields of blue and green PDs reached up to 15.07%and 28.22%,respectively.Furthermore,PA PDs were successfully applied to the highly efficient photocatalytic degradation for dyes:methylene blue(MB)and methyl orange(MO)were degraded by 89.9%and 93.8%within 20 min under visible light,respectively.
