M 0.2Ca 0.8TiO 3∶Pr 3+(M=Mg 2+, Sr 2+, Ba 2+, Zn 2+) long persistence red phosphors were prepared by solid state reaction. The influence of the partially replacing Ca 2+ in CaTiO 3 with Mg 2+, Sr 2+, ...M 0.2Ca 0.8TiO 3∶Pr 3+(M=Mg 2+, Sr 2+, Ba 2+, Zn 2+) long persistence red phosphors were prepared by solid state reaction. The influence of the partially replacing Ca 2+ in CaTiO 3 with Mg 2+, Sr 2+, Ba 2+, Zn 2+ on the excitation spectra, the emission spectra and the long persistence properties were studied. The results suggest that certain quantity of Mg 2+, Sr 2+, Ba 2+, Zn 2+ which partially replace Ca 2+ can enhance the luminescent intensity and prolong the afterglow persistence of the samples. The intensity of Mg 0.2Ca 0.8TiO 3∶Pr 3+ is above all of the samples. Take Mg 0.2Ca 0.8TiO 3∶Pr 3+ as the basic sample, the influence of Pr 3+ concentrations (C(Pr 3+)) on the long afterglow properties were also studied. The results suggest that when the C(Pr 3+) is 0.10% (mol fraction) the intensity of the sample is the highest. The excitation spectra of all these samples show broad band spectra ranging from 300～500 nm peaking at about 342 nm. The emission spectra also exhibit a broad band peaking at 613 nm (CaTiO 3∶Pr 3+ is 612 nm). XRD research indicates that the crystalline phases change due to the replacement of divalent metal ions.The research on the thermoluminescence spectra of Mg 0.2Ca 0.8TiO 3∶Pr 3+ indicates that the peak is at 107.35 ℃ and the depth of the trap energy is about 0 852 eV.展开更多
Ce^(3+),due to its broadband emission,has the potential to serve as a donor ion for energy transfer to achieve the possible efficient tunable multi-emission in materials.However,current related research primarily focu...Ce^(3+),due to its broadband emission,has the potential to serve as a donor ion for energy transfer to achieve the possible efficient tunable multi-emission in materials.However,current related research primarily focuses on photoluminescent(PL)phosphors,while studies on achieving tunable long persistent luminescence(LPL),particularly in glass materials,are insufficient.In this work,Ce-Tb codoped boroaluminate glass was synthesized using a high-temperature melting method under a reducing atmosphere.Under the influence of oxygen vacancy traps induced during the reduction of Ce^(4+)to Ce^(3+),glass samples exhibit an obvious LPL with a broadband center wavelength at 420 nm and a narrowband center wavelength at 547 nm,which correspond well to Ce^(3+)ions'd-f transitions and Tb^(3+)ions'f-f transitions,respectively.A reasonable Ce^(3+)doping amount achieves the optimal trap depth and concentration to enhance LPL intensity and duration.Additionally,it improves the PL intensity of Tb^(3+)by enhancing the energy transfer from Ce^(3+)to Tb^(3+),thereby enabling the glass to exhibit variable LPL colo rs ranging from blue to cyan.Finally,based on the PL and LPL characteristics of the samples,a dynamic encryption anticounterfeiting application is described.展开更多
The preparation, properties, expression and luminescent mechanism of self luminous material (SrAl 2O 4∶Eu 2+ , Dy 3+ ) were discussed. The long afterglow luminescent coating was prepared by adding proper l...The preparation, properties, expression and luminescent mechanism of self luminous material (SrAl 2O 4∶Eu 2+ , Dy 3+ ) were discussed. The long afterglow luminescent coating was prepared by adding proper luminescent powders SrAl 2O 4∶Eu 2+ , Dy 3+ and other aids into styrene/acrylic emulsion. The best prescription of the coating was defined. The properties of luminescent coating were determined. The primary factors which affect the coating properties were discussed.展开更多
A green long persistent luminescence（LPL） phosphor Ca3Ga4O9：Tb3＋/Zn2＋ was prepared. Ca3 Ga4 O9 matrix exhibits blue self-activated LPL due to the creation of intrinsic traps. When Tb3＋ is doped, the photolumines...A green long persistent luminescence（LPL） phosphor Ca3Ga4O9：Tb3＋/Zn2＋ was prepared. Ca3 Ga4 O9 matrix exhibits blue self-activated LPL due to the creation of intrinsic traps. When Tb3＋ is doped, the photoluminescence（PL） and LPL colors change from blue to green with their intensities significantly enhanced. The doping of Zn^（2＋） evidently improves the PL and LPL performances of the Ca3Ga4O9 matrix and Ca3Ga4O9：Tb^（3＋）. The thermoluminescence（TL） spectra show that a successive trap distribution is formed by multiple intrinsic traps with different depths in the Ca3 Ga4 O9 matrix, and the incorporation of Tb^（3＋） and Zn^（2＋） effectively increases the densities of these intrinsic traps. The existence of a successive trap distribution makes the Ca3 Ga4 O9：Tb^（3＋）/Zn^（2＋） phosphor exhibit thermally stable PL and LPL, It is indicated that this phosphor shows great promise for the application such as high-temperature LPL phosphor.展开更多
Near infrared to near infrared(NIR-NIR)photo-stimulated persistent luminescence(PSPL)has shown excellent potential in high-resolution bioimaging for deep tissues.However,the PSPL in NIR-Ⅱregion(900-1700 nm)is still l...Near infrared to near infrared(NIR-NIR)photo-stimulated persistent luminescence(PSPL)has shown excellent potential in high-resolution bioimaging for deep tissues.However,the PSPL in NIR-Ⅱregion(900-1700 nm)is still lacking.In this work,Ca_(2)Ga_(2)GeO_(7):Yb^(3+),Tb^(3+)(CGGYT)phosphor with unique lowdimensional crystal structure was synthesized by high-temperature solid-state reaction.Thanks to the carriers transferring from deep traps to shallow ones induced by low energy light,the 978 nm PSPL originating from ^(2)F_(5/2) to ^(2)F_(7/2) transition of Yb^(3+)induced by multimode stimulating(980 nm or WLED)is successfully realized after pre-excited by UV lamp.The NIR PSPL of the specimen can be repeatedly stimulated after placed in dark for 12 h.Moreover,the results indicate that codoping with Tb^(3+)can significantly enhance the NIR-ⅡPSPL owing to the quantum cutting persistent energy transfer(QC PET)from Tb^(3+)to Yb^(3+).Our study points to a new direction for the future development of multimode PSPL materials for bioimaging or multimode optical storage applications.展开更多
A series of Sr2A12SiO7 phosphors with fixed Eu2＋ concentration and various Tm3＋ concentrations were synthesized via a high temperature solid state reaction. The structure and luminescence properties of the samples w...A series of Sr2A12SiO7 phosphors with fixed Eu2＋ concentration and various Tm3＋ concentrations were synthesized via a high temperature solid state reaction. The structure and luminescence properties of the samples were characterized by X-ray powder diffraction （XRD）, photoluminescence （PL） spectra, decay curves, thermoluminescence （TL） glow curves as well as the photostimu- lated luminescence （PSL） spectra. Sr2A12SiO7：Eu2＋,Tm3＋ phosphors exhibited strong green phosphorescence and photostimulated lu- minescence originating from 4f65d1-4f7 transition of Eu2＋ after ultraviolet light stimulation. Deep traps were found by analyses on the phosphorescence decays and thermoluminescence spectra. It was also found that with increasing the time interval between UV excita- tion turn-off and stimulation turn-on, the photostimulated luminescence became stronger. This phenomenon resulted from the fact that the captured electron was retrapped by the deep traps. Compared with the Tm3＋-free sample, it was found that the PSL intensity was strongly enhanced in Tm3＋ eodoping samples.展开更多
A novel green long afterglow material CaGeO_(3):Tb^(3+)was synthesized by high temperature solid phase method.According to the experimental results,CaGeO_(3):Tb^(3+)is a green long persistent luminescent(LPL)material ...A novel green long afterglow material CaGeO_(3):Tb^(3+)was synthesized by high temperature solid phase method.According to the experimental results,CaGeO_(3):Tb^(3+)is a green long persistent luminescent(LPL)material with excellent performance.CaGeO_(3):Tb^(3+)shows LPL emission peak at 442,490.9,548.7,588.5 and 623.8 nm,corresponding to ^(5)D_(3) to^(7)F_(4)and^(5)D_(4)to^(7)F_(J)(J=6,5,4,3)transitions of Tb^(3+).Its CIE coordinates are(0.27,0.50),indicating that the afterglow emission is close to the light of green region.In addition,after the excitation source is turned off,the afterglow time is longer than 90 min.After an interval of 7 h,the photo-stimulation luminescence(PSL)can be observed by using 980 nm laser cyclic excitation.The thermoluminescence(ThL)results show that there are three types of traps in the material and their depths are 0.666,0.774 and 0.892 eV respectively,which are caused by the doping of Tb^(3+).All the results show that CaGeO_(3):Tb^(3+)is an excellent long afterglow luminescent material.展开更多
The research of long persistent luminescence(LPL)materials has yield brilliant results in many fields.However,the efforts are still needed for the regulation of the LPL performance.In this work,a series of LPL metal o...The research of long persistent luminescence(LPL)materials has yield brilliant results in many fields.However,the efforts are still needed for the regulation of the LPL performance.In this work,a series of LPL metal organic halides with rich halogen-bond interactions,Py-CdX_(2)(X=Cl,Br,I)were synthesized through self-assembly by Cd X_(2)and pyridine solvent.The steady-state emission redshifted and phosphorescence lifetime declined as the halogen atoms are aggravated.Three halides exhibit adjustable emission from blue to green and multiple phosphorescence from green to yellow at room temperature by changing the excitation wavelengths.Surprisingly,Py-CdX_(2)can emit the visible color-tunable LPL from green to yellow after removing different excitation sources at ambient conditions.Combing the results of theoretical calculation and experimental analysis,it is found that heavy atom effect and the rich intermolecular halogen bond help realize LPL and multiple triplet states originated from the pyridine ring and the halogens.展开更多
We developed bright yellow-emitting long persistent luminescence(LPL)materials Sr_(4)Al_(14)O_(25):Mn^(2+)and Sr_(4)Al_(14)O_(25):Mn^(2+),N(N=Zr^(4+),Ho^(3+),Er^(3+))by high temperature solid-state reaction.The additi...We developed bright yellow-emitting long persistent luminescence(LPL)materials Sr_(4)Al_(14)O_(25):Mn^(2+)and Sr_(4)Al_(14)O_(25):Mn^(2+),N(N=Zr^(4+),Ho^(3+),Er^(3+))by high temperature solid-state reaction.The addition of Zr^(4+),Ho^(3+)and Er^(3+)can regulate trap distributions and improve energy storage ability of the materials.The LPL perfo rmance of SAO:Mn^(2+),Ho^(3+)is optimal,considering LPL intensity and duration time.Bright LPL of SAO:Mn^(2+),Ho^(3+)can be observed for 3 h by naked eyes in dark after removing the excitation source.Profiles of LPL spectra are different from those of PL,because the two types of Mn^(2+)centers do not play equal parts in LPL and photoluminescence(PL).Trap depths of TL peaks centered at 354 K(peak 1)and 455 K(peak 2)are 0.60 and 0.72 eV,respectively.And peak 1 at 354 K is the effective TL peak responsible for LPL.In SAO:Mn^(2+),Ho^(3+),Mn^(2+)ions doped in Al^(3+)sites serve as emitting centers,and positively charged HoSr defects are the main effective trap centers.Finally,a feasible LPL mechanism of SAO:Mn^(2+),Ho^(3+)was proposed to clarify the generation process of LPL.展开更多
Long lasting strontium aluminate phosphors were synthesized by means of coated precipitation in the experiment. SrAl 2O 4 monoclinic phase with long afterglow was synthesized at 1 100 ℃ with the aid of H 3BO 3, and t...Long lasting strontium aluminate phosphors were synthesized by means of coated precipitation in the experiment. SrAl 2O 4 monoclinic phase with long afterglow was synthesized at 1 100 ℃ with the aid of H 3BO 3, and the synthetic temperature decreased about 100 ℃—150 ℃ than in solid state reaction. The process of heat treatment was studied by TG-DTA. The phase compositions of powders were analyzed by XRD. The micrographs of the samples were investigated by SEM and the luminescent properties were researched by optical spectrum. The effects of H 3BO 3 on the phase composition and microstructure of the calcined powders were investigated. The results indicated that H 3BO 3 accelerated the formation of SrAl 2O 4 by consuming the intermediate phase. The addition of Dy 2O 3 stimulated the afterglow property due to the increase in the depth of the trap center in the materials.展开更多
Organic afterglow materials have drawn increasing attention for their great potential in practical applications.Until now,most of them just show the lifetimes in milliseconds or seconds,while the realization of long p...Organic afterglow materials have drawn increasing attention for their great potential in practical applications.Until now,most of them just show the lifetimes in milliseconds or seconds,while the realization of long persistent luminescence(LPL)lasting for minutes or even hours is difficult.In 2017,Adachi and Kabe successfully realize the LPL with a duration longer than 1 hour in a purely organic system,which can be even comparable to some excellent inorganic materials.However,partially for the unclear structure-property relationship,organic LPL materials are still rather scarce,especially for the stable ones in air or aqueous solution.In this review,we present the recent progress in organic LPL,mainly focusing on the material design strategy and internal mechanism.It is anticipated that the deep understanding can be beneficial for the further development of organic LPL materials with good stability in air and even aqueous phase.展开更多
Ionically bonded organic metal halide perovskite-like luminescent materials,which incorporate organic cations and metal halides,have emerged as a versatile multicomponent material system.However,these materials still ...Ionically bonded organic metal halide perovskite-like luminescent materials,which incorporate organic cations and metal halides,have emerged as a versatile multicomponent material system.However,these materials still face challenges in terms of low phosphorescence quantum yields and limited long persistent luminescence(LPL)colors.Herein,we present the design and synthesis of an intraligand chargetransfer organic-based metal halide perovskite-like material,in which organic cations form a compact supramolecular hydrogen-bonded organic framework(HOF)structure,exhibiting crystallization-induced phosphorescence emission of ligand,while metal halides form a unique two-dimensional(2D)structure that displays intrinsic self-trapped excitons(STE)emission under the radiation of UV light.Notably,the metal halide hybrid is found to exhibit enhanced phosphorescent photoluminescence efficiency of up to 81.05%and tunable LPL from cyan to orange compared to the pristine organic phosphor,due to the structural distortion and scaffolding effects of 2D metal halides as well as a well-packed HOF structure.Optical characterizations and theoretical calculations reveal that charge transfer from organic cations and halogen to ligand as well as STE from inorganic layers are responsible for the tunable LPL.Meanwhile,the high-efficiency phosphorescent quantum yield is attributed to stronger hydrogen bond stacking as well as structural distortion of metal halogen bands.Thus,the obtained LPL provides potentials in anti-counterfeiting,security systems,and so on.展开更多
Ultralong organic afterglow materials are being actively explored as attractive candidates for a wide range of applications such as data storage,security inks,emergency lighting,etc.,due to their unique long-lived exc...Ultralong organic afterglow materials are being actively explored as attractive candidates for a wide range of applications such as data storage,security inks,emergency lighting,etc.,due to their unique long-lived excited state properties and inherent advantages of low cost,appreciable functionality and ease of preparation.In the last three years,much effort has been devoted to achieving efficient ultralong afterglow from organic small molecules,which possess controllable intermolecular interactions and defined energy levels,making them a good platform to suppress the non-radiative decays,hence stabilizing the excitons for efficient afterglow emissions at room temperature.Nevertheless,there has been a lack of reviews on how efficient ultralong organic afterglow can be systematically achieved from small molecular host-vip materials,which is not conducive to the development of the field.In this review,we have outlined and summarized small-molecule ultralong organic afterglow materials based on different emission mechanisms.We have included emission mechanisms involving ultralong room-temperature phosphorescence(URTP),ultralong thermally activated delayed fluorescence(UTADF)and organic long persistent luminescence(OLPL),where the latter two mechanisms have rarely been reported.In addition,challenges and future perspectives are discussed to emphasize the future directions.展开更多
Pure organic room-temperature phosphorescence(RTP)has drawn broad attention due to its long persistent luminescence and large Stokes shift.Although the doping strategy has become one of the most effective methods to c...Pure organic room-temperature phosphorescence(RTP)has drawn broad attention due to its long persistent luminescence and large Stokes shift.Although the doping strategy has become one of the most effective methods to construct organic RTP systems,there is still some fuzziness of impurities,mechanisms and luminescence regulation.This study develops a series of doping RTP systems based on exciplex,in which BPC@PPZ(where BPC is N-(4-bromophenyl)-carbazole,PPZ is 10-phenyl-10H-phenothiazine)achieved the highest quantum yield of 36.3%,while BPC@CE(where CE is coronene)showed the longest lifetime of 628.5 ms.The relevant data verify the mechanism that RTP comes from the charge transfer(CT)state of exciplex.Further,the introduction of Nile Red into the exciplex system results in the triple-singlet F?rster resonance energy transfer,exhibiting a red delayed fluorescence.Besides,when incorporating the coumarin derivatives into doping system,distinct ^(1)CT*&^(3)CT*states are generated through the CT process,accompanying a brand-new long persistent luminescence excited by visible light.These findings present an approach to regulate the CT state for achieving different persistent luminescence in the multicomponent system.展开更多
The electrochemiluminescence(ECL)behavior of a multiresonance thermally activated delayed fluorescence molecule has been investigated for the first time by means of ECL‐voltage curves,newly designed ECL‐time observa...The electrochemiluminescence(ECL)behavior of a multiresonance thermally activated delayed fluorescence molecule has been investigated for the first time by means of ECL‐voltage curves,newly designed ECL‐time observatory,and ECL spectroscopy.The compound,Mes3DiKTa,shows complex ECL behavior,including a delayed onset time of 5 ms for ECL generation in both the annihilation pathway and the coreactant route,which we attribute to organic long‐persistent ECL(OLECL).Triplet‐triplet annihilation,thermally activated delayed fluorescence and uncompensated solution resistance cannot be ruled out as contributing mechanisms to the ECL.A very long ECL emission decay was attributed to OLECL as well.The absolute ECL efficiencies of Mes3DiKTa were enhanced and reached 0.0013%in annihilation route and 1.1%for the coreactant system,which are superior to those of most other organic ECL materials.It is plausible that ECL materials with comparable behavior as Mes3DiKTa are desirable in applications such as ECL sensing,imaging,and light‐emitting devices.展开更多
文摘M 0.2Ca 0.8TiO 3∶Pr 3+(M=Mg 2+, Sr 2+, Ba 2+, Zn 2+) long persistence red phosphors were prepared by solid state reaction. The influence of the partially replacing Ca 2+ in CaTiO 3 with Mg 2+, Sr 2+, Ba 2+, Zn 2+ on the excitation spectra, the emission spectra and the long persistence properties were studied. The results suggest that certain quantity of Mg 2+, Sr 2+, Ba 2+, Zn 2+ which partially replace Ca 2+ can enhance the luminescent intensity and prolong the afterglow persistence of the samples. The intensity of Mg 0.2Ca 0.8TiO 3∶Pr 3+ is above all of the samples. Take Mg 0.2Ca 0.8TiO 3∶Pr 3+ as the basic sample, the influence of Pr 3+ concentrations (C(Pr 3+)) on the long afterglow properties were also studied. The results suggest that when the C(Pr 3+) is 0.10% (mol fraction) the intensity of the sample is the highest. The excitation spectra of all these samples show broad band spectra ranging from 300～500 nm peaking at about 342 nm. The emission spectra also exhibit a broad band peaking at 613 nm (CaTiO 3∶Pr 3+ is 612 nm). XRD research indicates that the crystalline phases change due to the replacement of divalent metal ions.The research on the thermoluminescence spectra of Mg 0.2Ca 0.8TiO 3∶Pr 3+ indicates that the peak is at 107.35 ℃ and the depth of the trap energy is about 0 852 eV.
基金Project supported by the Department of Science and Technology of Zhejiang Province,China(2024C01192)。
文摘Ce^(3+),due to its broadband emission,has the potential to serve as a donor ion for energy transfer to achieve the possible efficient tunable multi-emission in materials.However,current related research primarily focuses on photoluminescent(PL)phosphors,while studies on achieving tunable long persistent luminescence(LPL),particularly in glass materials,are insufficient.In this work,Ce-Tb codoped boroaluminate glass was synthesized using a high-temperature melting method under a reducing atmosphere.Under the influence of oxygen vacancy traps induced during the reduction of Ce^(4+)to Ce^(3+),glass samples exhibit an obvious LPL with a broadband center wavelength at 420 nm and a narrowband center wavelength at 547 nm,which correspond well to Ce^(3+)ions'd-f transitions and Tb^(3+)ions'f-f transitions,respectively.A reasonable Ce^(3+)doping amount achieves the optimal trap depth and concentration to enhance LPL intensity and duration.Additionally,it improves the PL intensity of Tb^(3+)by enhancing the energy transfer from Ce^(3+)to Tb^(3+),thereby enabling the glass to exhibit variable LPL colo rs ranging from blue to cyan.Finally,based on the PL and LPL characteristics of the samples,a dynamic encryption anticounterfeiting application is described.
文摘The preparation, properties, expression and luminescent mechanism of self luminous material (SrAl 2O 4∶Eu 2+ , Dy 3+ ) were discussed. The long afterglow luminescent coating was prepared by adding proper luminescent powders SrAl 2O 4∶Eu 2+ , Dy 3+ and other aids into styrene/acrylic emulsion. The best prescription of the coating was defined. The properties of luminescent coating were determined. The primary factors which affect the coating properties were discussed.
基金supported by the National Natural Science Foundation of China(11774138)the Society Development Foundation of Yunnan Province(2016FA021)the Kunming University of Science and Technology(KKSY201632046)
文摘A green long persistent luminescence（LPL） phosphor Ca3Ga4O9：Tb3＋/Zn2＋ was prepared. Ca3 Ga4 O9 matrix exhibits blue self-activated LPL due to the creation of intrinsic traps. When Tb3＋ is doped, the photoluminescence（PL） and LPL colors change from blue to green with their intensities significantly enhanced. The doping of Zn^（2＋） evidently improves the PL and LPL performances of the Ca3Ga4O9 matrix and Ca3Ga4O9：Tb^（3＋）. The thermoluminescence（TL） spectra show that a successive trap distribution is formed by multiple intrinsic traps with different depths in the Ca3 Ga4 O9 matrix, and the incorporation of Tb^（3＋） and Zn^（2＋） effectively increases the densities of these intrinsic traps. The existence of a successive trap distribution makes the Ca3 Ga4 O9：Tb^（3＋）/Zn^（2＋） phosphor exhibit thermally stable PL and LPL, It is indicated that this phosphor shows great promise for the application such as high-temperature LPL phosphor.
基金Project supported by the National Natural Science Foundation of China-Yunnan Joint Fund(U1902222)the National Natural Science Foundation of China(11774138,11664022,51862020 and 11804255)the Natural Science Foundation of Yunnan Province(2019HC016)。
文摘Near infrared to near infrared(NIR-NIR)photo-stimulated persistent luminescence(PSPL)has shown excellent potential in high-resolution bioimaging for deep tissues.However,the PSPL in NIR-Ⅱregion(900-1700 nm)is still lacking.In this work,Ca_(2)Ga_(2)GeO_(7):Yb^(3+),Tb^(3+)(CGGYT)phosphor with unique lowdimensional crystal structure was synthesized by high-temperature solid-state reaction.Thanks to the carriers transferring from deep traps to shallow ones induced by low energy light,the 978 nm PSPL originating from ^(2)F_(5/2) to ^(2)F_(7/2) transition of Yb^(3+)induced by multimode stimulating(980 nm or WLED)is successfully realized after pre-excited by UV lamp.The NIR PSPL of the specimen can be repeatedly stimulated after placed in dark for 12 h.Moreover,the results indicate that codoping with Tb^(3+)can significantly enhance the NIR-ⅡPSPL owing to the quantum cutting persistent energy transfer(QC PET)from Tb^(3+)to Yb^(3+).Our study points to a new direction for the future development of multimode PSPL materials for bioimaging or multimode optical storage applications.
基金supported by the National Natural Science Foundation of China(1137404411104024)+2 种基金Natural Science Foundation of Liaoning Province(2014025010)Fundamental Research Funds for the Central Universities(31320143273132015143)
文摘A series of Sr2A12SiO7 phosphors with fixed Eu2＋ concentration and various Tm3＋ concentrations were synthesized via a high temperature solid state reaction. The structure and luminescence properties of the samples were characterized by X-ray powder diffraction （XRD）, photoluminescence （PL） spectra, decay curves, thermoluminescence （TL） glow curves as well as the photostimu- lated luminescence （PSL） spectra. Sr2A12SiO7：Eu2＋,Tm3＋ phosphors exhibited strong green phosphorescence and photostimulated lu- minescence originating from 4f65d1-4f7 transition of Eu2＋ after ultraviolet light stimulation. Deep traps were found by analyses on the phosphorescence decays and thermoluminescence spectra. It was also found that with increasing the time interval between UV excita- tion turn-off and stimulation turn-on, the photostimulated luminescence became stronger. This phenomenon resulted from the fact that the captured electron was retrapped by the deep traps. Compared with the Tm3＋-free sample, it was found that the PSL intensity was strongly enhanced in Tm3＋ eodoping samples.
基金Project supported by the State Key Research Projects of Shandong Natural Science Foundation(ZR2020KB019)the fund of"Two-Hundred Talent"Plan of Yantai City+1 种基金the National Natural Science Foundation of China(11974013)the Natural Science Foundation of Fujian Province(2022J011270)。
文摘A novel green long afterglow material CaGeO_(3):Tb^(3+)was synthesized by high temperature solid phase method.According to the experimental results,CaGeO_(3):Tb^(3+)is a green long persistent luminescent(LPL)material with excellent performance.CaGeO_(3):Tb^(3+)shows LPL emission peak at 442,490.9,548.7,588.5 and 623.8 nm,corresponding to ^(5)D_(3) to^(7)F_(4)and^(5)D_(4)to^(7)F_(J)(J=6,5,4,3)transitions of Tb^(3+).Its CIE coordinates are(0.27,0.50),indicating that the afterglow emission is close to the light of green region.In addition,after the excitation source is turned off,the afterglow time is longer than 90 min.After an interval of 7 h,the photo-stimulation luminescence(PSL)can be observed by using 980 nm laser cyclic excitation.The thermoluminescence(ThL)results show that there are three types of traps in the material and their depths are 0.666,0.774 and 0.892 eV respectively,which are caused by the doping of Tb^(3+).All the results show that CaGeO_(3):Tb^(3+)is an excellent long afterglow luminescent material.
基金financially supported by National Natural Science Foundation of China(No.22101162)Start-up Foundation of Shaanxi University of Science&Technology(No.126022036)。
文摘The research of long persistent luminescence(LPL)materials has yield brilliant results in many fields.However,the efforts are still needed for the regulation of the LPL performance.In this work,a series of LPL metal organic halides with rich halogen-bond interactions,Py-CdX_(2)(X=Cl,Br,I)were synthesized through self-assembly by Cd X_(2)and pyridine solvent.The steady-state emission redshifted and phosphorescence lifetime declined as the halogen atoms are aggravated.Three halides exhibit adjustable emission from blue to green and multiple phosphorescence from green to yellow at room temperature by changing the excitation wavelengths.Surprisingly,Py-CdX_(2)can emit the visible color-tunable LPL from green to yellow after removing different excitation sources at ambient conditions.Combing the results of theoretical calculation and experimental analysis,it is found that heavy atom effect and the rich intermolecular halogen bond help realize LPL and multiple triplet states originated from the pyridine ring and the halogens.
基金Project supported by the National Natural Science Foundation of China(51802137)the Natural Science Foundation of Shandong Province of China(ZR2019BEM010)+1 种基金the State Key Research Projects of Shandong Natural Science Foundation(ZR2020KB019)Yantai High End Talent Introduction"Double Hundred Plan"Special Fund,the Research Fund of Ludong University(ZR2021004)。
文摘We developed bright yellow-emitting long persistent luminescence(LPL)materials Sr_(4)Al_(14)O_(25):Mn^(2+)and Sr_(4)Al_(14)O_(25):Mn^(2+),N(N=Zr^(4+),Ho^(3+),Er^(3+))by high temperature solid-state reaction.The addition of Zr^(4+),Ho^(3+)and Er^(3+)can regulate trap distributions and improve energy storage ability of the materials.The LPL perfo rmance of SAO:Mn^(2+),Ho^(3+)is optimal,considering LPL intensity and duration time.Bright LPL of SAO:Mn^(2+),Ho^(3+)can be observed for 3 h by naked eyes in dark after removing the excitation source.Profiles of LPL spectra are different from those of PL,because the two types of Mn^(2+)centers do not play equal parts in LPL and photoluminescence(PL).Trap depths of TL peaks centered at 354 K(peak 1)and 455 K(peak 2)are 0.60 and 0.72 eV,respectively.And peak 1 at 354 K is the effective TL peak responsible for LPL.In SAO:Mn^(2+),Ho^(3+),Mn^(2+)ions doped in Al^(3+)sites serve as emitting centers,and positively charged HoSr defects are the main effective trap centers.Finally,a feasible LPL mechanism of SAO:Mn^(2+),Ho^(3+)was proposed to clarify the generation process of LPL.
文摘Long lasting strontium aluminate phosphors were synthesized by means of coated precipitation in the experiment. SrAl 2O 4 monoclinic phase with long afterglow was synthesized at 1 100 ℃ with the aid of H 3BO 3, and the synthetic temperature decreased about 100 ℃—150 ℃ than in solid state reaction. The process of heat treatment was studied by TG-DTA. The phase compositions of powders were analyzed by XRD. The micrographs of the samples were investigated by SEM and the luminescent properties were researched by optical spectrum. The effects of H 3BO 3 on the phase composition and microstructure of the calcined powders were investigated. The results indicated that H 3BO 3 accelerated the formation of SrAl 2O 4 by consuming the intermediate phase. The addition of Dy 2O 3 stimulated the afterglow property due to the increase in the depth of the trap center in the materials.
基金the National Natural Science Foundation of China(No.52273191,22235006)the Chinese Chemical Society Young Talent Lifting Project,the Natural Science Foundation of Tianjin City(No.22JCYBJC00760)+1 种基金the starting Grants of Tianjin University and Tianjin Government,the Open Fund of the State Key Laboratory of Luminescent Materials and Devices(South China University of Technology)(No.2024-skllmd-04)Independent Innovation Fund of Tianjin University(No.2023XPD-0014),for financial support.
文摘Organic afterglow materials have drawn increasing attention for their great potential in practical applications.Until now,most of them just show the lifetimes in milliseconds or seconds,while the realization of long persistent luminescence(LPL)lasting for minutes or even hours is difficult.In 2017,Adachi and Kabe successfully realize the LPL with a duration longer than 1 hour in a purely organic system,which can be even comparable to some excellent inorganic materials.However,partially for the unclear structure-property relationship,organic LPL materials are still rather scarce,especially for the stable ones in air or aqueous solution.In this review,we present the recent progress in organic LPL,mainly focusing on the material design strategy and internal mechanism.It is anticipated that the deep understanding can be beneficial for the further development of organic LPL materials with good stability in air and even aqueous phase.
基金National Natural Science Foundation of China,Grant/Award Numbers:22101162,92261114。
文摘Ionically bonded organic metal halide perovskite-like luminescent materials,which incorporate organic cations and metal halides,have emerged as a versatile multicomponent material system.However,these materials still face challenges in terms of low phosphorescence quantum yields and limited long persistent luminescence(LPL)colors.Herein,we present the design and synthesis of an intraligand chargetransfer organic-based metal halide perovskite-like material,in which organic cations form a compact supramolecular hydrogen-bonded organic framework(HOF)structure,exhibiting crystallization-induced phosphorescence emission of ligand,while metal halides form a unique two-dimensional(2D)structure that displays intrinsic self-trapped excitons(STE)emission under the radiation of UV light.Notably,the metal halide hybrid is found to exhibit enhanced phosphorescent photoluminescence efficiency of up to 81.05%and tunable LPL from cyan to orange compared to the pristine organic phosphor,due to the structural distortion and scaffolding effects of 2D metal halides as well as a well-packed HOF structure.Optical characterizations and theoretical calculations reveal that charge transfer from organic cations and halogen to ligand as well as STE from inorganic layers are responsible for the tunable LPL.Meanwhile,the high-efficiency phosphorescent quantum yield is attributed to stronger hydrogen bond stacking as well as structural distortion of metal halogen bands.Thus,the obtained LPL provides potentials in anti-counterfeiting,security systems,and so on.
基金financial support from the NSF of China(62275217,T.Y.)Natural Science Basic Research Programme of Shaanxi(2024JC-JCQN-51,T.Y.)a start-up grant from City University of Hong Kong(9610637,C.-Y.C.).
文摘Ultralong organic afterglow materials are being actively explored as attractive candidates for a wide range of applications such as data storage,security inks,emergency lighting,etc.,due to their unique long-lived excited state properties and inherent advantages of low cost,appreciable functionality and ease of preparation.In the last three years,much effort has been devoted to achieving efficient ultralong afterglow from organic small molecules,which possess controllable intermolecular interactions and defined energy levels,making them a good platform to suppress the non-radiative decays,hence stabilizing the excitons for efficient afterglow emissions at room temperature.Nevertheless,there has been a lack of reviews on how efficient ultralong organic afterglow can be systematically achieved from small molecular host-vip materials,which is not conducive to the development of the field.In this review,we have outlined and summarized small-molecule ultralong organic afterglow materials based on different emission mechanisms.We have included emission mechanisms involving ultralong room-temperature phosphorescence(URTP),ultralong thermally activated delayed fluorescence(UTADF)and organic long persistent luminescence(OLPL),where the latter two mechanisms have rarely been reported.In addition,challenges and future perspectives are discussed to emphasize the future directions.
基金supported by the National Key Research and Development Program of China(2022YFB3203500)the National Natural Science Foundation of China(22125803,T2488302,22020102006,22205062)+2 种基金the Science and Technology Commission of Shanghai Municipality(24DX1400200)the Guangxi Department of Science and Technology(AA23062016)the Fundamental Research Funds for the Central Universities。
文摘Pure organic room-temperature phosphorescence(RTP)has drawn broad attention due to its long persistent luminescence and large Stokes shift.Although the doping strategy has become one of the most effective methods to construct organic RTP systems,there is still some fuzziness of impurities,mechanisms and luminescence regulation.This study develops a series of doping RTP systems based on exciplex,in which BPC@PPZ(where BPC is N-(4-bromophenyl)-carbazole,PPZ is 10-phenyl-10H-phenothiazine)achieved the highest quantum yield of 36.3%,while BPC@CE(where CE is coronene)showed the longest lifetime of 628.5 ms.The relevant data verify the mechanism that RTP comes from the charge transfer(CT)state of exciplex.Further,the introduction of Nile Red into the exciplex system results in the triple-singlet F?rster resonance energy transfer,exhibiting a red delayed fluorescence.Besides,when incorporating the coumarin derivatives into doping system,distinct ^(1)CT*&^(3)CT*states are generated through the CT process,accompanying a brand-new long persistent luminescence excited by visible light.These findings present an approach to regulate the CT state for achieving different persistent luminescence in the multicomponent system.
基金supported in part by the National Natural Science Foundation of China(22075149,22105104,62075102,and 22275097)Jiangsu Specially-Appointed Professor Plan,the Six Talent Plan of Jiangsu Province(XCL-049),HuaLi Talents Program of Nanjing University of Posts and Telecommunications,the Open Fund of the State Key Laboratory of Luminescent Materials and Devices(South China University of Technology)(2022-skllmd-01)+3 种基金the Open Research Fund of Songshan Lake Materials Laboratory(2022SLABFN16)the Innovation and Entrepreneurship Program of Jiangsu Province,China(JSSCBS20210536)the Fifth 333-Project of Jiangsu Province of China(BRA2019080)Nanjing University of Posts and Telecommunications Start-up Fund(NY220151 and NY219007).
基金supports to this study by Natural Sciences and Engineering Research Council Canada(NSERC,DG RGPIN‐2018‐06556 and SPG STPGP‐2016‐493924)Canada Foundation of Innovation/Ontario Innovation Trust(CFI/OIT,9040)The University of Western Ontario.
文摘The electrochemiluminescence(ECL)behavior of a multiresonance thermally activated delayed fluorescence molecule has been investigated for the first time by means of ECL‐voltage curves,newly designed ECL‐time observatory,and ECL spectroscopy.The compound,Mes3DiKTa,shows complex ECL behavior,including a delayed onset time of 5 ms for ECL generation in both the annihilation pathway and the coreactant route,which we attribute to organic long‐persistent ECL(OLECL).Triplet‐triplet annihilation,thermally activated delayed fluorescence and uncompensated solution resistance cannot be ruled out as contributing mechanisms to the ECL.A very long ECL emission decay was attributed to OLECL as well.The absolute ECL efficiencies of Mes3DiKTa were enhanced and reached 0.0013%in annihilation route and 1.1%for the coreactant system,which are superior to those of most other organic ECL materials.It is plausible that ECL materials with comparable behavior as Mes3DiKTa are desirable in applications such as ECL sensing,imaging,and light‐emitting devices.
