The mismatch between the AM1.5G spectrum and the photovoltaic (PV) cells absorption is one of the most limiting factors for PV performance.To overcome this constraint through the enhancement of solar energy harvesting...The mismatch between the AM1.5G spectrum and the photovoltaic (PV) cells absorption is one of the most limiting factors for PV performance.To overcome this constraint through the enhancement of solar energy harvesting,luminescent downshifting (LDS) layers are very promising to shape the incident sunlight and,thus,we report here the use of Tb^3+- and Eu^3+-doped organic-inorganic hybrid materials as LDS layers on Si PV cells.Electrical measurements on the PV cell,done before and after the deposition of the LDS layers,confirm the positive effect of the coatings on the cell’s performance in the UV spectral region.The maximum delivered power and the maximum absolute external quantum efficiency increased 14% and 27%,respectively.Moreover,a solar powered car race was organized in which the small vehicle containing the coated PV cells presented a relative increase of 9% in the velocity,when compared to that with the uncoated one.展开更多
The design and fabrication of rare earth ions incorporated into the inorganic/organic hybrid materials have attracted growing attention for seeking improved optical properties and photofunctional performances.In this ...The design and fabrication of rare earth ions incorporated into the inorganic/organic hybrid materials have attracted growing attention for seeking improved optical properties and photofunctional performances.In this paper,a novel hybrid composite based on the layered rare earth hydroxides was successfully prepared by the ion-exchange and intercalation chemical process.The rare earth elements in the composite contain gadolinium(Gd)and europium(Eu)and the molar ratio of Gd to Eu is kept constant at 1.9:0.1.Organic sodium dodecyl sulfonate and dye coumarin-3-carboxyllc acid are simultaneously incorporated into the layered rare earth hydroxides as supporting agent and light-harvesting antenna,respectively.The resulting hybrid layered rare earth hydroxides exhibit the enlarged interlayer distance with about 2.60 nm,and the chemical composition was confirmed through X-ray diffraction,carbon,hydrogen and nitrogen(CHN)elemental analysis,infrared spectroscopy,and thermogravimetric analysis.The layered solid compound shows the characteristic red emission corresponding to the^(5)D_(0)→^(7)F_(2)transition of Eu^(3+)ion,and the luminescence intensity of the optimized compound is greatly enhanced as compared to its corresponding nitrate and the hybrid composite without the introduction of dye molecule.The hybrid layered rare earth hydroxides can be exfoliated into bright colloidal solution,which show superior recognition capability to Cu^(2+)ion with the distinct luminescence quenching.The large quenching constant(1.4×10^(4)L/mol)and low detection limit(0.35μmol/L)are achieved for Cu^(2+)ion,implying a"turn-off"fluorescent sensor for Cu^(2+)detection.Moreover,a transparent film was prepared based on the colloidal solution and displays the typical red emission in folded shape.The new hybrid compound with enhanced luminescence and excellent photofunctional performances is expected to be applied in the fields of fluorescent sensing and flexible optical devices.展开更多
In the present work,we prepared three isostructural lanthanide(Ln) coordination polymers(CPs).namely [Ln(Hhpc)(phen)(NO_(3))](Ln=Gd(1),La(2),Y(3),H_(3)hpc=5-hydroxy-1 H-pyrazole-3-carboxyIic acid,phen=1,10-phenanthrol...In the present work,we prepared three isostructural lanthanide(Ln) coordination polymers(CPs).namely [Ln(Hhpc)(phen)(NO_(3))](Ln=Gd(1),La(2),Y(3),H_(3)hpc=5-hydroxy-1 H-pyrazole-3-carboxyIic acid,phen=1,10-phenanthroline) by hydrothermal method.Their structures were characterized by single crystal X-ray diffraction,Fourier transform infrared spectrum,elemental analysis,powder X-ray diffraction and thermal gravimetric analysis.CPs 1-3 are isostrutural and exhibit two-dimensional(2 D)wavy layered structure constructed from inorganic chains,in which equivalent eight coordinated Ln^(3+) ions are linked through carboxylate groups.The three dimensional supramolecular structure is further formed by hydrogen bonding.The photocatalytic experiments show that CPs 2 and 3 exhibit good photocatalytic performances under visible light in degradation of methylene blue organic dye.The photocatalytic degradation efficiencies in 90 min are about 86.19% and 93.60% for CPs 2 and 3,respectively.The photocatalytic degradation mechanisms have been proposed through photoelectrochemical and trapping radical experiments.展开更多
The Sr2 CeO4:Ln3+(Ln=Eu,Dy)fine phosphor particles were prepared by a facile wet chemical approach,in which the consecutive hydrothermal-combustion reaction was performed.The doping of Ln3+into Sr2 CeO4 has little inf...The Sr2 CeO4:Ln3+(Ln=Eu,Dy)fine phosphor particles were prepared by a facile wet chemical approach,in which the consecutive hydrothermal-combustion reaction was performed.The doping of Ln3+into Sr2 CeO4 has little influence on the structure of host,and the as-prepared samples display wellcrystallized spherical or elliptical shape with an average particle size at about 100-200 nm.For Eu3+ions-doped Sr2 CeO4,with the increase of Eu3+-doping concentration,the blue light emission band with the maximum at 468 nm originating from a Ce4+→O2-charge transfer of the host decreases obviously and the characteristic red light emission of Eu3+(5 D0→7 F2 transition at 618 nm)is enhanced gradually.Simultaneously,the fluorescent lifetime of the broadband emission of Sr2 CeO4 decreases with the doping of Eu3+,indicating an efficient energy transfer from the host to the doping Eu3+ions.The ene rgy transfer efficiency from the host to Eu3+was investigated in detail,and the emitting color of Sr2 CeO4:Eu3+can be easily tuned from blue to red by varying the doping concentration of Eu3+ions.Moreover,the luminescence of Dy3+-doped Sr2 CeO4 was also studied.Similar energy transfer pheno menon can be observed,and the incorporation of Dy3+into Sr2 CeO4 host leads to the characteristic emission of 4 F9/2→6 H15/2(488 nm,blue light)and 4 F9/2→6 H13/2(574 nm,yellow light)of Dy3+.The Sr2 CeO4:Ln3+fine particles with tunable luminescence are quite beneficial for its potential applications in the optoelectronic fields.展开更多
The general use of smartphones assigns additional relevance to QR codes as a privileged tool to the Internet of Things(IoT).Crucial for QR codes is the evolution to IoT-connected smart tags with enhanced storage capac...The general use of smartphones assigns additional relevance to QR codes as a privileged tool to the Internet of Things(IoT).Crucial for QR codes is the evolution to IoT-connected smart tags with enhanced storage capacity and secure accesses.Using the concept of super-modules(s-modules)built from adjacent spatial multiplexed modules with regular geometrical shapes,assisted by colour multiplexing,we modelled and design a single QR code with,at least,the triple storage capacity of an analogous size black/white QR code,acting as a smart-tag ensuring restrict access and trackability.The s-modules are printed using luminescent low-cost and eco-friendly inks based on organic-inorganic hybrids modified by lanthanides with multiplexed colour emission in the orthogonal RGB space.The access to the restrict information is attained only under UV irradiation and encrypted for secure transmission.The concept of active QR codes for smart trackability and IoT was materialised through the development of a free friendly-user mobile app.展开更多
文摘The mismatch between the AM1.5G spectrum and the photovoltaic (PV) cells absorption is one of the most limiting factors for PV performance.To overcome this constraint through the enhancement of solar energy harvesting,luminescent downshifting (LDS) layers are very promising to shape the incident sunlight and,thus,we report here the use of Tb^3+- and Eu^3+-doped organic-inorganic hybrid materials as LDS layers on Si PV cells.Electrical measurements on the PV cell,done before and after the deposition of the LDS layers,confirm the positive effect of the coatings on the cell’s performance in the UV spectral region.The maximum delivered power and the maximum absolute external quantum efficiency increased 14% and 27%,respectively.Moreover,a solar powered car race was organized in which the small vehicle containing the coated PV cells presented a relative increase of 9% in the velocity,when compared to that with the uncoated one.
基金Project supported by the National Natural Science Foundation of China(51972097)。
文摘The design and fabrication of rare earth ions incorporated into the inorganic/organic hybrid materials have attracted growing attention for seeking improved optical properties and photofunctional performances.In this paper,a novel hybrid composite based on the layered rare earth hydroxides was successfully prepared by the ion-exchange and intercalation chemical process.The rare earth elements in the composite contain gadolinium(Gd)and europium(Eu)and the molar ratio of Gd to Eu is kept constant at 1.9:0.1.Organic sodium dodecyl sulfonate and dye coumarin-3-carboxyllc acid are simultaneously incorporated into the layered rare earth hydroxides as supporting agent and light-harvesting antenna,respectively.The resulting hybrid layered rare earth hydroxides exhibit the enlarged interlayer distance with about 2.60 nm,and the chemical composition was confirmed through X-ray diffraction,carbon,hydrogen and nitrogen(CHN)elemental analysis,infrared spectroscopy,and thermogravimetric analysis.The layered solid compound shows the characteristic red emission corresponding to the^(5)D_(0)→^(7)F_(2)transition of Eu^(3+)ion,and the luminescence intensity of the optimized compound is greatly enhanced as compared to its corresponding nitrate and the hybrid composite without the introduction of dye molecule.The hybrid layered rare earth hydroxides can be exfoliated into bright colloidal solution,which show superior recognition capability to Cu^(2+)ion with the distinct luminescence quenching.The large quenching constant(1.4×10^(4)L/mol)and low detection limit(0.35μmol/L)are achieved for Cu^(2+)ion,implying a"turn-off"fluorescent sensor for Cu^(2+)detection.Moreover,a transparent film was prepared based on the colloidal solution and displays the typical red emission in folded shape.The new hybrid compound with enhanced luminescence and excellent photofunctional performances is expected to be applied in the fields of fluorescent sensing and flexible optical devices.
基金Project supported by the National Natural Science Foundation of China (51872140,51973173)the College Students Training Program of Innovation and Entrepreneurship of Jiangsu Province (2021114630082)+1 种基金postgraduate Research&Practice Innovation Program of Jiangsu Province (SJCX20_1027 and SJCX21_1328)the NSF for Universities in Jiangsu Province (18KJB150013)。
文摘In the present work,we prepared three isostructural lanthanide(Ln) coordination polymers(CPs).namely [Ln(Hhpc)(phen)(NO_(3))](Ln=Gd(1),La(2),Y(3),H_(3)hpc=5-hydroxy-1 H-pyrazole-3-carboxyIic acid,phen=1,10-phenanthroline) by hydrothermal method.Their structures were characterized by single crystal X-ray diffraction,Fourier transform infrared spectrum,elemental analysis,powder X-ray diffraction and thermal gravimetric analysis.CPs 1-3 are isostrutural and exhibit two-dimensional(2 D)wavy layered structure constructed from inorganic chains,in which equivalent eight coordinated Ln^(3+) ions are linked through carboxylate groups.The three dimensional supramolecular structure is further formed by hydrogen bonding.The photocatalytic experiments show that CPs 2 and 3 exhibit good photocatalytic performances under visible light in degradation of methylene blue organic dye.The photocatalytic degradation efficiencies in 90 min are about 86.19% and 93.60% for CPs 2 and 3,respectively.The photocatalytic degradation mechanisms have been proposed through photoelectrochemical and trapping radical experiments.
基金Project supported by National Natural Science Foundation of China(51972097)This work was financially supported by the Science Foundation of Hebei Normal University,China(L2019K11).This work was also financially supported by the project WINLEDS—POCI-01-0145-FEDER-030351 and developed within the scope of the project CICECO-Aveiro Institute of Materials,FCT Ref.UID/CTM/50011/2019,financed by national funds through the FCT/MCTES.
文摘The Sr2 CeO4:Ln3+(Ln=Eu,Dy)fine phosphor particles were prepared by a facile wet chemical approach,in which the consecutive hydrothermal-combustion reaction was performed.The doping of Ln3+into Sr2 CeO4 has little influence on the structure of host,and the as-prepared samples display wellcrystallized spherical or elliptical shape with an average particle size at about 100-200 nm.For Eu3+ions-doped Sr2 CeO4,with the increase of Eu3+-doping concentration,the blue light emission band with the maximum at 468 nm originating from a Ce4+→O2-charge transfer of the host decreases obviously and the characteristic red light emission of Eu3+(5 D0→7 F2 transition at 618 nm)is enhanced gradually.Simultaneously,the fluorescent lifetime of the broadband emission of Sr2 CeO4 decreases with the doping of Eu3+,indicating an efficient energy transfer from the host to the doping Eu3+ions.The ene rgy transfer efficiency from the host to Eu3+was investigated in detail,and the emitting color of Sr2 CeO4:Eu3+can be easily tuned from blue to red by varying the doping concentration of Eu3+ions.Moreover,the luminescence of Dy3+-doped Sr2 CeO4 was also studied.Similar energy transfer pheno menon can be observed,and the incorporation of Dy3+into Sr2 CeO4 host leads to the characteristic emission of 4 F9/2→6 H15/2(488 nm,blue light)and 4 F9/2→6 H13/2(574 nm,yellow light)of Dy3+.The Sr2 CeO4:Ln3+fine particles with tunable luminescence are quite beneficial for its potential applications in the optoelectronic fields.
基金This work was developed within the scope of the project CICECO-Aveiro Institute of Materials(UIDB/50011/2020&UIDP/50011/2020)Instituto de Telecomunicações(FCT Ref.UIDB/50008/2020-UIDP/50008/2020)WinLEDs(POCI-01-0145-FEDER-030351)and Graphsense(POCI-01-0145-FEDER-032072)financed by national funds through the FCT/MEC and when appropriate co-financed by FEDER under the PT2020 Partnership through European Regional Development Fund(ERDF)in the frame of Operational Competitiveness and Internationalization Programme(POCI).SFHC thanks Solar-Flex,CENTRO-01-0145-FEDER-030186.A.M.Botas and M.Ferro from the University of Aveiro are acknowledged for help in the hyperspectral and scanning electronic microscopies,respectively。
文摘The general use of smartphones assigns additional relevance to QR codes as a privileged tool to the Internet of Things(IoT).Crucial for QR codes is the evolution to IoT-connected smart tags with enhanced storage capacity and secure accesses.Using the concept of super-modules(s-modules)built from adjacent spatial multiplexed modules with regular geometrical shapes,assisted by colour multiplexing,we modelled and design a single QR code with,at least,the triple storage capacity of an analogous size black/white QR code,acting as a smart-tag ensuring restrict access and trackability.The s-modules are printed using luminescent low-cost and eco-friendly inks based on organic-inorganic hybrids modified by lanthanides with multiplexed colour emission in the orthogonal RGB space.The access to the restrict information is attained only under UV irradiation and encrypted for secure transmission.The concept of active QR codes for smart trackability and IoT was materialised through the development of a free friendly-user mobile app.