Di-calcium magnesium silicate(Ca_(2)MgSi_(2)O_(7))doped with various concentrations(1.0 mol%,2.0 mol%,2.5 mol%,and 3.0 mol%)of dysprosium(Ⅲ)was prepared using a high-temperature technique named as solid state reactio...Di-calcium magnesium silicate(Ca_(2)MgSi_(2)O_(7))doped with various concentrations(1.0 mol%,2.0 mol%,2.5 mol%,and 3.0 mol%)of dysprosium(Ⅲ)was prepared using a high-temperature technique named as solid state reaction method.The sample with 2.5 mol%of dysprosium(Ⅲ)underwent X-ray diffraction(XRD)characterization to confirm the proper phase formation in the sample.Observed XRD pattern matched significantly with crystallographic open database(Card No.96-210-6180)with a significantly high figure of merit(0.84).Photoluminescence(PL)excitation and emission spectra were also recorded.PL excitation spectrum of Ca_(2)MgSi_(2)O_(7)doped with 2.5 mol%of dysprosium(Ⅲ)exhibited a most prominent peak at 395 nm,therefore,the emission spectra of the samples were monitored at 395 nm excitation.The emission spectra exhibited prominent peaks centered at 483 nm(blue),577 nm(yellow),and 664 nm(orange red)due to the transitions ^(4)F_(9/2)→^(6)H_(15/2),^(4)F_(9/2)→^(6)H_(13/2),and ^(4)F_(9/2)→^(6)H_(11/2),respectively.The Commission Internationale de L’Eclairage(CIE)of this emission spectra was found at(0.304,0.340)which lies in the white light region.Keeping the objective to evaluate the emitted white light for its suitability in light-emitting diode(LED)application,color rendering index(CRI)and color correlated temperature(CCT)were also calculated.Radiation life time was estimated using Judd-Ofelt analysis.展开更多
Organic metal halides with white-light emissions have shown significant application prospects in the fields of solid-state lighting and displays, but their structural design and synthesis remain a major challenge. Her...Organic metal halides with white-light emissions have shown significant application prospects in the fields of solid-state lighting and displays, but their structural design and synthesis remain a major challenge. Here, the material design concept of functional units has been applied to prepare a zero-dimensional (oD) organic anti-mony halide (1-BMP)_(5)(SbCl_(5))_(2)SbCl_(4) with two luminescent centers from the inorganic units and the organic units, emitting red emission about 670 nm and cyan emission about 508 nm respectively, combined to form white light. Based on the photoluminescence (PL), the time-resolved PL analysis and density functional theory (DFT) calculation, it is shown that the red and cyan emission comes from STEs related to inorganic units [SbCl_(5)]^(2-) and the fluorescence of organic cations 1-BMP^(+), respectively. This work provides new methods and ideas for the development of low-cost and eco-friendly white emission phosphors for single-component solid-state WLEDs.展开更多
The Au/Al2O3/Al metal/insulator/metal junction(MIMJ) and Au/SiO2/Si metal/insulator/Si junction(MISJ) have been constructed successfully. The light emission of these junctions was mediated by surface plasmon-polariton...The Au/Al2O3/Al metal/insulator/metal junction(MIMJ) and Au/SiO2/Si metal/insulator/Si junction(MISJ) have been constructed successfully. The light emission of these junctions was mediated by surface plasmon-polaritons(SPPs) under surface roughness. The light emission from MISJ was more uniform and stable than that from MIMJ. The light power of MISJ was about 2~3 orders higher than that of MIMJ. The light emission spectrum of MISJ was analyzed especially. In the spectrum, there was one main peak located at the wavelength of 610 nm^640 nm, which was mainly due to the couple of SPP with the surface roughness at the Au/air and Au/SiO2 interfaces. A weak peak located at the shorter wavelength region in the spectrum was also found, which was caused by the direct radiation of doped-Si plasma oscillation.展开更多
Carbon dots(CDs)are metal-free fluorescent materials that can be used in optical and electronic devices,but few studies have focused on one-step synthesis routes for CDs with tunable color and high photoluminescence q...Carbon dots(CDs)are metal-free fluorescent materials that can be used in optical and electronic devices,but few studies have focused on one-step synthesis routes for CDs with tunable color and high photoluminescence quantum yield(PLQY).Herein,CDs with tunable light emission were synthesized using a novel amide-assisted solvothermal approach.The as-prepared CDs were well dispersed and homogeneous,with average diameters of approximately 2.0–4.0 nm,depending on the dopants.Owing to the surface states with different ratios of nitrogen-and oxygen-related species,different CDs can exhibit blue,green,red,or white emission with relatively high PLQYs of 61.6%,41.3%,29.1%and 19.7%,respectively.XPS measurements,in conjunction with DFT calculations,indicate that nitrogen substitution(pyridinic/pyrrolic nitrogen)dominates the blue emission,while introducing oxygen functional groups lowered the LUMO energy level,which resulted in redder emission.In addition,the CDs are demonstrated as a bioimaging probe in both in vitro and in vivo assays,and the white light CDs have been demonstrated to be potential fluorescent materials for white-light-emitting diode(WLED).展开更多
In this work, we designed and synthesized cationic carbon dots(CDs) with a size distribution of 1.6–3.7 nm, which exhibited dark blue fluorescence in the aqueous solution. Based on its excellent luminescence properti...In this work, we designed and synthesized cationic carbon dots(CDs) with a size distribution of 1.6–3.7 nm, which exhibited dark blue fluorescence in the aqueous solution. Based on its excellent luminescence properties, we used it as an energy donor to construct a sequential artificial light-harvesting system(LHS) by employing the energy-matching dyes eosin Y disodium salt(EY) and sulforhodamine101(SR101), which could regulate the white light emission(Commission Internationale de l'Eclairage(CIE) coordinate:(0.30, 0.31)) with the energy transfer efficiency(ΦET) of 53.9% and 20.0%. Moreover, a single-step artificial LHS with white light emission(0.32, 0.28) can be constructed directly using CDs and dye solvent 43(SR) with ΦETand antenna effect(AE) of 48.8% and 6.5, respectively. More importantly,CDs-based artificial LHSs were firstly used in photocatalytic of α-bromoacetophenone, with a yield of90%. This work not only provides a new strategy for constructing CDs-based LHSs, but also opens up a new application for further applying the energy harvested in CDs-based LHSs to the field of the aqueous solution photocatalysis.展开更多
A series of triphe nylamine(TPA)derivatives with various substituent groups were prepared and showed different absorption and fluorescence characteristics due to the substituent effect.On account of the existence of p...A series of triphe nylamine(TPA)derivatives with various substituent groups were prepared and showed different absorption and fluorescence characteristics due to the substituent effect.On account of the existence of pyridine units,these TPA derivatives exhibited acid-induced tunable multicolor fluorescence emission including white light emission.In addition,acid-induced fluorescence regulation of these compounds has been also realized in the solid state,which enable them to be successfully constructed the stimuli-responsive fluorescent films and fluorescent inks for inkjet printing.展开更多
The Eu^3＋/Ag co-doped rare earth disilicate Y2Si2O7 microcrystal was synthesized by sol-gel method. Through controlling the thermal treatment process of YzSi2OT：EU3＋/Ag precursor, various phases （amorphous, α, ...The Eu^3＋/Ag co-doped rare earth disilicate Y2Si2O7 microcrystal was synthesized by sol-gel method. Through controlling the thermal treatment process of YzSi2OT：EU3＋/Ag precursor, various phases （amorphous, α, β, γ, δ） were prepared. White light emis- sion was observed under UV light excitation in the samples heavily doped with Ag. The white light was realized by combining the intense red emission of Eu3＋, the green emission attributed to the very small molecule-like, non-plasmonic Ag particles （ML-Ag-particles）, and the blue emission due to Ag ions. Results demonstrated that Eu3＋/Ag co-doped Y2Si207 microcrystal could be potentially applied as white light emission phosphors for UV LED chips.展开更多
We experimentally demonstrate an efficient enhancement of luminescence from two-dimensional(2D) hexagonal photonic crystal(PC) airbridge double-heterostructure microcavity with Er-doped silicon(Si) as light emitters o...We experimentally demonstrate an efficient enhancement of luminescence from two-dimensional(2D) hexagonal photonic crystal(PC) airbridge double-heterostructure microcavity with Er-doped silicon(Si) as light emitters on siliconon-insulator(SOI) wafer at room temperature.A single sharp resonant peak at 1 529.6 nm dominates the photoluminescence(PL) spectrum with the pumping power of 12.5 m W.The obvious red shift and the degraded quality factor(Q-factor) of resonant peak appear with the pumping power increasing,and the maximum measured Q-factor of 4 905 is achieved at the pumping power of 1.5 m W.The resonant peak is observed to shift depending on the structural parameters of PC,which indicates a possible method to control the wavelength of enhanced luminescence for Si-based light emitters based on PC microcavity.展开更多
The plasmon-enhanced light emission of rutile TiO2（110） surface has been investigated by a low-temperature scanning tunneling microscope （STM）. We found that the photon emission arises from the inelastic electron ...The plasmon-enhanced light emission of rutile TiO2（110） surface has been investigated by a low-temperature scanning tunneling microscope （STM）. We found that the photon emission arises from the inelastic electron tunneling between the STM tip and the conduction band or defect states of TiO2（110）. In contrast to the Au（111） surface, the maximum photon energy as a function of the bias voltage clearly deviates from the linear scaling behavior, suggesting the non-negligible effect of the STM tip on the band structure of TiO2. By performing differential conductance （dl/dV） measurements, it was revealed that such a deviation is not related to the tip-induced band bending, but is attributed to the image charge effect of the metal tip, which significantly shifts the band edges of the TiO2（110） towards the Femi level （EF） during the tunneling process. This work not only sheds new lights onto the understanding of plasmon-enhanced light emission of semiconductor surfaces, but also opens up a new avenue for engineering the plasmon-mediated interfacial charge transfer in molecular and semiconducting materials.展开更多
Band structure, electron distribution, direct-bandgap light emission, and optical gain of tensile strained, n-doped Ge at different temperatures were calculated. We found that the heating effects not only increase the...Band structure, electron distribution, direct-bandgap light emission, and optical gain of tensile strained, n-doped Ge at different temperatures were calculated. We found that the heating effects not only increase the electron occupancy rate in the Γ valley of Ge by thermal excitation, but also reduce the energy difference between its Γ valley and L valley. However,the light emission enhancement of Ge induced by the heating effects is weakened with increasing tensile strain and n-doping concentration. This phenomenon could be explained by that Ge is more similar to a direct bandgap material under tensile strain and n-doping. The heating effects also increase the optical gain of tensile strained, n-doped Ge at low temperature, but decrease it at high temperature. At high temperature, the hole and electron distributions become more flat, which prevent obtaining higher optical gain. Meanwhile, the heating effects also increase the free-carrier absorption. Therefore, to obtain a higher net maximum gain, the tensile strained, n-doped Ge films on Si should balance the gain increased by the heating effects and the optical loss induced by the free-carrier absorption.展开更多
Fabricated are the double-barrier light emission tunnel junctions successfully. Introduced are the fabrication process and light emission characteristics. The spectra of the junctions are measured and analyzed especia...Fabricated are the double-barrier light emission tunnel junctions successfully. Introduced are the fabrication process and light emission characteristics. The spectra of the junctions are measured and analyzed especially. Their spectrum wavelength including main wave peak(locates at 450 nm^500 nm) of the double-barrier junction shows a "blue shift" in comparison with that of the single-barrier Metal/Insulator/Semiconductor(MIS) or Metal/Insulator/Metal(MIM) junction(wave peak locates at 620 nm^740 nm). This phenomenon should be due to the occurrence of the electron resonant tunneling in the double-barrier junction.展开更多
The development of high-performance organic blue light-emitting emitters is in urgent to act as an excitation source to contribute the white light generation.On the other hand,the investigation on optical waveguides h...The development of high-performance organic blue light-emitting emitters is in urgent to act as an excitation source to contribute the white light generation.On the other hand,the investigation on optical waveguides have been received increasing attentions because they can manipulate the light propagation accurately in the microscale to boost the optoelectronic and energy conversion applications.In this work,we facilely prepared a deep-blue aggregation-induced emission(AIE)dye,namely TPP-4OMe,which shows high luminescent efficiency,narrow emission band and good stability in the aggregate state.TPP-4OMe can be fabricated as deep-blue AIE microfibers readily with definite morphology and composition.Based on the AIE microfibers,the active waveguide to transmit deep-blue emission signals can be achieved with a very low optical loss coefficient(α)of 6.7×10^(−3)dBμm^(−1).Meanwhile,the full-visible broadband low-loss passive waveguide can be well performed with these AIE microfibers,which has never been observed in the pure organic crystals.More interestingly,the excellent properties of AIE microfibers enable them to act as a wave-guiding excitation source,resulting in a distinct and pure white light emission.The present work not only provides excellent blue light-emitting materials but also bridges the waveguide to realize the efficient white light emission to accelerate the practical applications.展开更多
The measurement of emissions from the window material of sapphire was performed through multi-wavelength pyrometer and spontaneous spectroscopic techniques in the pressure range of 40 -120 GPa. The results showed that...The measurement of emissions from the window material of sapphire was performed through multi-wavelength pyrometer and spontaneous spectroscopic techniques in the pressure range of 40 -120 GPa. The results showed that the spectral distribution with wavelength clearly fit well with the grey-body spectrum. We have analyzed the emissions and discovered they mostly came from the shear banding, which is a typical thermal radiation. The radiance intensity changing linearly with time revealed it was a volume effect. All of the data from pyrometer can be explained by the model of Boslough＇s study, especially for pres- sures over megabar. The color temperature of shocked sapphire changing with increased stress disagrees with the computed melt curve which is likely explained by the differcnt phase structures of sapphire.展开更多
Surface-plasmon （SP） enhancement of amorphous-silicon-nitride （a-SiNx） light emission with single-layer gold （Au） waveguides is experimentally demonstrated through time-resolved photoluminescence measure- ment. ...Surface-plasmon （SP） enhancement of amorphous-silicon-nitride （a-SiNx） light emission with single-layer gold （Au） waveguides is experimentally demonstrated through time-resolved photoluminescence measure- ment. The a-SiN~ active layer with strong steady-state photoluminescence at 560 nm is prepared by plasma-enhanced chemical vapor deposition, and ricated by magnetron sputtering. The maximum the Au waveguide on the top of the a-SiNx layer is lab- Purcell factor value of -3 is achieved with identified SP resonance of the Au waveguide at -530 nm.展开更多
Although silicon is an indirect semiconductor, light emission from silicon is governed by the same gener- alized Planck＇s radiation law as the emission from direct semiconductors. The emission intensity is given by t...Although silicon is an indirect semiconductor, light emission from silicon is governed by the same gener- alized Planck＇s radiation law as the emission from direct semiconductors. The emission intensity is given by the absorptance of the volume in which there is a difference of the quasi Fermi energies. A difference of the Fermi energies may result h＇om the absorption of external light （photoluminescence） or from the injection of electrons and holes via selective contacts （electroluminescence）. The quantum efficiency may be larger than 0.5 for carrier densities below 10^15 cm^-3. At larger densities, non-radiative recombination, in particular Auger recombination dominates. At all carrier densities, the relation between emission intensity and difference of the quasi Fermi energies is maintained. Since this difference is equal to the voltage of a properly designed solar cell, luminescence is the key indicator of material quality for solar cells.展开更多
ZnS films were deposited by pulsed laser deposition （PLD） on porous silicon （PS） substrates formed by electrochemical anodization of p-type （100） silicon wafer. The photoluminescence （PL） spectra of ZnS/PS com...ZnS films were deposited by pulsed laser deposition （PLD） on porous silicon （PS） substrates formed by electrochemical anodization of p-type （100） silicon wafer. The photoluminescence （PL） spectra of ZnS/PS composites were measured at room temperature. Under different excitation wavelengths, the relative integrated intensities of the red light emission from PS layers and the blue-green emission from ZnS films had different values. After samples were annealed in vacuum at different temperatures （200, 300, and 400 ~C） for 30 min respectively, a new green emission located at around 550 nm appeared in the PL spectra of all ZnS/PS samples, and all of the ZnS/PS composites had a broad PL band （450 - 700 nm） in the visible region, exhibiting intensively white light emission.展开更多
Owing to their outstanding optoelectronic properties,all-inorganic CsPbBr_(3) perovskite nanocrystals(NCs)are regarded as excellent materials for various optoelectronic applications.Unfortunately,their practical appli...Owing to their outstanding optoelectronic properties,all-inorganic CsPbBr_(3) perovskite nanocrystals(NCs)are regarded as excellent materials for various optoelectronic applications.Unfortunately,their practical applications are limited by poor stability against water,heat,and polar solvents.Here,we propose a facile synthesis strategy for CsPbBr_(3)@Cs_(4)PbBr_(6) NCs via tetraoctylammonium bromide ligand induction at room temperature.The resulting CsPbBr_(3)@Cs_(4)PbBr_(6) NCs show a high photoluminescence quantum yield of 94%.In order to prevent Cs4PbBr6 from being converted back to CsPbBr_(3) NCs when exposed to water,a second coating layer of SiO2 is formed on the surface of the CsPbBr_(3)@Cs_(4)PbBr_(6) NCs by the facile hydrolysis of tetramethoxysilane.The resulting CsPbBr_(3)@Cs_(4)PbBr_(6)/SiO_(2) NCs with their double coating structure have outstanding stability against not only a polar solvent(ethanol)but also water and heat.The as-prepared CsPbBr_(3)@Cs_(4)PbBr_(6)/SiO_(2) NCs serve as green emitters in efficient white light-emitting diodes(WLEDs)with a high color rendering index(CRI)of 91 and a high power efficiency 59.87 lm W−1.Furthermore,the use of these WLEDs in visible light communication(VLC)results in a maximum rate of 44.53 Mbps,suggesting the great potential of the reported methods and materials for solid-state illumination and VLC.展开更多
Fluorescent organic materials that exhibit unique aggregation-induced emission have been utilized for various applications,including white light emission(WLE).The materials typically rely on composite designs involvin...Fluorescent organic materials that exhibit unique aggregation-induced emission have been utilized for various applications,including white light emission(WLE).The materials typically rely on composite designs involving a mixture of compounds emitting at different wavelengths of light.To overcome the limitations offered by the design of such composite mixtures,tremendous efforts were also emphasized in developing single-molecule substrates that emit white light.The white light by either method is typically controlled by the solvent polarity,energy and charge transfer,host-vip interactions,gelation,or embedding in the polymer or organic frameworks.This article briefly reviews various molecules exhibiting aggregation-induced emission behavior and emitting white light.展开更多
Cubic silicon carbide （SIC） nanowires are synthesized in a catalyst-assisted process. The nanowires with diameter of ～ 40 nm exhibit strong blue light emission at room temperature under ultraviolet （UV） femtoseco...Cubic silicon carbide （SIC） nanowires are synthesized in a catalyst-assisted process. The nanowires with diameter of ～ 40 nm exhibit strong blue light emission at room temperature under ultraviolet （UV） femtosecond laser excitation. The photon energy of peak emission is higher than the energy bandgap of cubic SiC which shows involvement of quantum confinement effect. The ultrafast fluorescence is deconvoluted by Monte-Carlo method. The results show two ultrafast decay processes whose lifetimes are about 26 and 567 ps respectively. The mechanisms of such ultrafast processes are discussed.展开更多
γ-LiAlO2 phosphor was synthesized using the cellulose-citric acid sol-gel method, and its light emission and energy transfer properties were investigated. Excitation and emission spectrum analysis revealed a decrease...γ-LiAlO2 phosphor was synthesized using the cellulose-citric acid sol-gel method, and its light emission and energy transfer properties were investigated. Excitation and emission spectrum analysis revealed a decrease in intensity of the spectrum as the amount of Mn2＋ doping increased. Blasse＇s equation determined the maximum distance for energy transfer between Mn2＋ ions as 4.3142 nm. Dexter＇s theory verifies that the mechanism of energy transfer between Mn2＋ ions conforms to an electric dipole and electric quadrupole interaction.展开更多
文摘Di-calcium magnesium silicate(Ca_(2)MgSi_(2)O_(7))doped with various concentrations(1.0 mol%,2.0 mol%,2.5 mol%,and 3.0 mol%)of dysprosium(Ⅲ)was prepared using a high-temperature technique named as solid state reaction method.The sample with 2.5 mol%of dysprosium(Ⅲ)underwent X-ray diffraction(XRD)characterization to confirm the proper phase formation in the sample.Observed XRD pattern matched significantly with crystallographic open database(Card No.96-210-6180)with a significantly high figure of merit(0.84).Photoluminescence(PL)excitation and emission spectra were also recorded.PL excitation spectrum of Ca_(2)MgSi_(2)O_(7)doped with 2.5 mol%of dysprosium(Ⅲ)exhibited a most prominent peak at 395 nm,therefore,the emission spectra of the samples were monitored at 395 nm excitation.The emission spectra exhibited prominent peaks centered at 483 nm(blue),577 nm(yellow),and 664 nm(orange red)due to the transitions ^(4)F_(9/2)→^(6)H_(15/2),^(4)F_(9/2)→^(6)H_(13/2),and ^(4)F_(9/2)→^(6)H_(11/2),respectively.The Commission Internationale de L’Eclairage(CIE)of this emission spectra was found at(0.304,0.340)which lies in the white light region.Keeping the objective to evaluate the emitted white light for its suitability in light-emitting diode(LED)application,color rendering index(CRI)and color correlated temperature(CCT)were also calculated.Radiation life time was estimated using Judd-Ofelt analysis.
基金the National Natural Science Foundation of China(22476220,22336007)the China Postdoctoral Science Foundation(2024M753736)the Guangdong Basic Research Center of Excellence for Functional Molecular Engineering(31000-42080002).
文摘Organic metal halides with white-light emissions have shown significant application prospects in the fields of solid-state lighting and displays, but their structural design and synthesis remain a major challenge. Here, the material design concept of functional units has been applied to prepare a zero-dimensional (oD) organic anti-mony halide (1-BMP)_(5)(SbCl_(5))_(2)SbCl_(4) with two luminescent centers from the inorganic units and the organic units, emitting red emission about 670 nm and cyan emission about 508 nm respectively, combined to form white light. Based on the photoluminescence (PL), the time-resolved PL analysis and density functional theory (DFT) calculation, it is shown that the red and cyan emission comes from STEs related to inorganic units [SbCl_(5)]^(2-) and the fluorescence of organic cations 1-BMP^(+), respectively. This work provides new methods and ideas for the development of low-cost and eco-friendly white emission phosphors for single-component solid-state WLEDs.
基金National Natural Science Foundation of China(69576006)
文摘The Au/Al2O3/Al metal/insulator/metal junction(MIMJ) and Au/SiO2/Si metal/insulator/Si junction(MISJ) have been constructed successfully. The light emission of these junctions was mediated by surface plasmon-polaritons(SPPs) under surface roughness. The light emission from MISJ was more uniform and stable than that from MIMJ. The light power of MISJ was about 2~3 orders higher than that of MIMJ. The light emission spectrum of MISJ was analyzed especially. In the spectrum, there was one main peak located at the wavelength of 610 nm^640 nm, which was mainly due to the couple of SPP with the surface roughness at the Au/air and Au/SiO2 interfaces. A weak peak located at the shorter wavelength region in the spectrum was also found, which was caused by the direct radiation of doped-Si plasma oscillation.
基金the financial support from the Chenguang Scholar Project of Shanghai Education Commission(Nos.19CG52,19CG53)National Natural Science Foundation of China(No.62071300)+3 种基金Science and Technology Commission of Shanghai Municipality(Nos.19ZR1435200,20490761100)Program of Shanghai Academic/Technology Research Leader(No.19XD1422900)Cross-program of Medical&Engineering(University of Shanghai for Science and Technology)Foundation of State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering(No.2021-K33)。
文摘Carbon dots(CDs)are metal-free fluorescent materials that can be used in optical and electronic devices,but few studies have focused on one-step synthesis routes for CDs with tunable color and high photoluminescence quantum yield(PLQY).Herein,CDs with tunable light emission were synthesized using a novel amide-assisted solvothermal approach.The as-prepared CDs were well dispersed and homogeneous,with average diameters of approximately 2.0–4.0 nm,depending on the dopants.Owing to the surface states with different ratios of nitrogen-and oxygen-related species,different CDs can exhibit blue,green,red,or white emission with relatively high PLQYs of 61.6%,41.3%,29.1%and 19.7%,respectively.XPS measurements,in conjunction with DFT calculations,indicate that nitrogen substitution(pyridinic/pyrrolic nitrogen)dominates the blue emission,while introducing oxygen functional groups lowered the LUMO energy level,which resulted in redder emission.In addition,the CDs are demonstrated as a bioimaging probe in both in vitro and in vivo assays,and the white light CDs have been demonstrated to be potential fluorescent materials for white-light-emitting diode(WLED).
基金the financial support from the National Natural Science Foundation of China (Nos.52205210 and 22002075)the Natural Science Foundation of Shandong Province (Nos.ZR2020MB018 and ZR2022QE033)。
文摘In this work, we designed and synthesized cationic carbon dots(CDs) with a size distribution of 1.6–3.7 nm, which exhibited dark blue fluorescence in the aqueous solution. Based on its excellent luminescence properties, we used it as an energy donor to construct a sequential artificial light-harvesting system(LHS) by employing the energy-matching dyes eosin Y disodium salt(EY) and sulforhodamine101(SR101), which could regulate the white light emission(Commission Internationale de l'Eclairage(CIE) coordinate:(0.30, 0.31)) with the energy transfer efficiency(ΦET) of 53.9% and 20.0%. Moreover, a single-step artificial LHS with white light emission(0.32, 0.28) can be constructed directly using CDs and dye solvent 43(SR) with ΦETand antenna effect(AE) of 48.8% and 6.5, respectively. More importantly,CDs-based artificial LHSs were firstly used in photocatalytic of α-bromoacetophenone, with a yield of90%. This work not only provides a new strategy for constructing CDs-based LHSs, but also opens up a new application for further applying the energy harvested in CDs-based LHSs to the field of the aqueous solution photocatalysis.
基金supported by the State Key Laboratory of Fine Chemicals(No.KF1801)。
文摘A series of triphe nylamine(TPA)derivatives with various substituent groups were prepared and showed different absorption and fluorescence characteristics due to the substituent effect.On account of the existence of pyridine units,these TPA derivatives exhibited acid-induced tunable multicolor fluorescence emission including white light emission.In addition,acid-induced fluorescence regulation of these compounds has been also realized in the solid state,which enable them to be successfully constructed the stimuli-responsive fluorescent films and fluorescent inks for inkjet printing.
基金Project supported by the National Natural Science Foundation of China(11074232,11274288,21002097,11304300)the National Basic Research Program of China(2011CB932801,2012CB933702)Ministry of Education of China(20123402110034)
文摘The Eu^3＋/Ag co-doped rare earth disilicate Y2Si2O7 microcrystal was synthesized by sol-gel method. Through controlling the thermal treatment process of YzSi2OT：EU3＋/Ag precursor, various phases （amorphous, α, β, γ, δ） were prepared. White light emis- sion was observed under UV light excitation in the samples heavily doped with Ag. The white light was realized by combining the intense red emission of Eu3＋, the green emission attributed to the very small molecule-like, non-plasmonic Ag particles （ML-Ag-particles）, and the blue emission due to Ag ions. Results demonstrated that Eu3＋/Ag co-doped Y2Si207 microcrystal could be potentially applied as white light emission phosphors for UV LED chips.
基金supported by the National Natural Science Foundation of China(No.61205044)
文摘We experimentally demonstrate an efficient enhancement of luminescence from two-dimensional(2D) hexagonal photonic crystal(PC) airbridge double-heterostructure microcavity with Er-doped silicon(Si) as light emitters on siliconon-insulator(SOI) wafer at room temperature.A single sharp resonant peak at 1 529.6 nm dominates the photoluminescence(PL) spectrum with the pumping power of 12.5 m W.The obvious red shift and the degraded quality factor(Q-factor) of resonant peak appear with the pumping power increasing,and the maximum measured Q-factor of 4 905 is achieved at the pumping power of 1.5 m W.The resonant peak is observed to shift depending on the structural parameters of PC,which indicates a possible method to control the wavelength of enhanced luminescence for Si-based light emitters based on PC microcavity.
基金Project supported by the National Key R&D Program of China(Grant Nos.2016YFA0300901 and 2017YFA0205003)the National Natural Science Foundation of China(Grant Nos.11634001 and 21725302)the Key Research Program of the Chinese Academy of Sciences(Grant No.XDPB08-1)
文摘The plasmon-enhanced light emission of rutile TiO2（110） surface has been investigated by a low-temperature scanning tunneling microscope （STM）. We found that the photon emission arises from the inelastic electron tunneling between the STM tip and the conduction band or defect states of TiO2（110）. In contrast to the Au（111） surface, the maximum photon energy as a function of the bias voltage clearly deviates from the linear scaling behavior, suggesting the non-negligible effect of the STM tip on the band structure of TiO2. By performing differential conductance （dl/dV） measurements, it was revealed that such a deviation is not related to the tip-induced band bending, but is attributed to the image charge effect of the metal tip, which significantly shifts the band edges of the TiO2（110） towards the Femi level （EF） during the tunneling process. This work not only sheds new lights onto the understanding of plasmon-enhanced light emission of semiconductor surfaces, but also opens up a new avenue for engineering the plasmon-mediated interfacial charge transfer in molecular and semiconducting materials.
基金Project supported by the National Basic Research Development Program of China(Grant No.2013CB632103)the National Natural Science Foundation of China(Grant Nos.61377045,61435013,and 61176013)
文摘Band structure, electron distribution, direct-bandgap light emission, and optical gain of tensile strained, n-doped Ge at different temperatures were calculated. We found that the heating effects not only increase the electron occupancy rate in the Γ valley of Ge by thermal excitation, but also reduce the energy difference between its Γ valley and L valley. However,the light emission enhancement of Ge induced by the heating effects is weakened with increasing tensile strain and n-doping concentration. This phenomenon could be explained by that Ge is more similar to a direct bandgap material under tensile strain and n-doping. The heating effects also increase the optical gain of tensile strained, n-doped Ge at low temperature, but decrease it at high temperature. At high temperature, the hole and electron distributions become more flat, which prevent obtaining higher optical gain. Meanwhile, the heating effects also increase the free-carrier absorption. Therefore, to obtain a higher net maximum gain, the tensile strained, n-doped Ge films on Si should balance the gain increased by the heating effects and the optical loss induced by the free-carrier absorption.
基金National Natural Science Foundation of China(69576006)
文摘Fabricated are the double-barrier light emission tunnel junctions successfully. Introduced are the fabrication process and light emission characteristics. The spectra of the junctions are measured and analyzed especially. Their spectrum wavelength including main wave peak(locates at 450 nm^500 nm) of the double-barrier junction shows a "blue shift" in comparison with that of the single-barrier Metal/Insulator/Semiconductor(MIS) or Metal/Insulator/Metal(MIM) junction(wave peak locates at 620 nm^740 nm). This phenomenon should be due to the occurrence of the electron resonant tunneling in the double-barrier junction.
基金National Natural Science Foundation of China,Grant/Award Numbers:22275072,11804120,61827822,51620105009Guangdong Basic and Applied Basic Research Foundation,Grant/Award Number:2023A1515030209+2 种基金Research Projects from Guangzhou,Grant/Award Number:2023A03J0018Shenzhen Key Laboratory of Functional Aggregate Materials,Grant/Award Number:ZDSYS20211021111400001the Science Technology Innovation Commission of Shenzhen Municipality,Grant/Award Numbers:KQTD20210811090142053,JCYJ20220818103007014。
文摘The development of high-performance organic blue light-emitting emitters is in urgent to act as an excitation source to contribute the white light generation.On the other hand,the investigation on optical waveguides have been received increasing attentions because they can manipulate the light propagation accurately in the microscale to boost the optoelectronic and energy conversion applications.In this work,we facilely prepared a deep-blue aggregation-induced emission(AIE)dye,namely TPP-4OMe,which shows high luminescent efficiency,narrow emission band and good stability in the aggregate state.TPP-4OMe can be fabricated as deep-blue AIE microfibers readily with definite morphology and composition.Based on the AIE microfibers,the active waveguide to transmit deep-blue emission signals can be achieved with a very low optical loss coefficient(α)of 6.7×10^(−3)dBμm^(−1).Meanwhile,the full-visible broadband low-loss passive waveguide can be well performed with these AIE microfibers,which has never been observed in the pure organic crystals.More interestingly,the excellent properties of AIE microfibers enable them to act as a wave-guiding excitation source,resulting in a distinct and pure white light emission.The present work not only provides excellent blue light-emitting materials but also bridges the waveguide to realize the efficient white light emission to accelerate the practical applications.
基金support provided by the National Natural Science Foundation of China (Grant Nos. 10874141,10974160 and 10299040)the Foundation of Center Universities (Grant No.SWJTU112T23)
文摘The measurement of emissions from the window material of sapphire was performed through multi-wavelength pyrometer and spontaneous spectroscopic techniques in the pressure range of 40 -120 GPa. The results showed that the spectral distribution with wavelength clearly fit well with the grey-body spectrum. We have analyzed the emissions and discovered they mostly came from the shear banding, which is a typical thermal radiation. The radiance intensity changing linearly with time revealed it was a volume effect. All of the data from pyrometer can be explained by the model of Boslough＇s study, especially for pres- sures over megabar. The color temperature of shocked sapphire changing with increased stress disagrees with the computed melt curve which is likely explained by the differcnt phase structures of sapphire.
基金supported by the National Basic Research Program of China(Nos.2011CBA00608 and 2011CBA00303)the National Natural Science Foundation of China(Nos.61036011 and 61036010)
文摘Surface-plasmon （SP） enhancement of amorphous-silicon-nitride （a-SiNx） light emission with single-layer gold （Au） waveguides is experimentally demonstrated through time-resolved photoluminescence measure- ment. The a-SiN~ active layer with strong steady-state photoluminescence at 560 nm is prepared by plasma-enhanced chemical vapor deposition, and ricated by magnetron sputtering. The maximum the Au waveguide on the top of the a-SiNx layer is lab- Purcell factor value of -3 is achieved with identified SP resonance of the Au waveguide at -530 nm.
文摘Although silicon is an indirect semiconductor, light emission from silicon is governed by the same gener- alized Planck＇s radiation law as the emission from direct semiconductors. The emission intensity is given by the absorptance of the volume in which there is a difference of the quasi Fermi energies. A difference of the Fermi energies may result h＇om the absorption of external light （photoluminescence） or from the injection of electrons and holes via selective contacts （electroluminescence）. The quantum efficiency may be larger than 0.5 for carrier densities below 10^15 cm^-3. At larger densities, non-radiative recombination, in particular Auger recombination dominates. At all carrier densities, the relation between emission intensity and difference of the quasi Fermi energies is maintained. Since this difference is equal to the voltage of a properly designed solar cell, luminescence is the key indicator of material quality for solar cells.
基金the Natural Science Foundation of Shandong Province under Grant No.Y2002A09.
文摘ZnS films were deposited by pulsed laser deposition （PLD） on porous silicon （PS） substrates formed by electrochemical anodization of p-type （100） silicon wafer. The photoluminescence （PL） spectra of ZnS/PS composites were measured at room temperature. Under different excitation wavelengths, the relative integrated intensities of the red light emission from PS layers and the blue-green emission from ZnS films had different values. After samples were annealed in vacuum at different temperatures （200, 300, and 400 ~C） for 30 min respectively, a new green emission located at around 550 nm appeared in the PL spectra of all ZnS/PS samples, and all of the ZnS/PS composites had a broad PL band （450 - 700 nm） in the visible region, exhibiting intensively white light emission.
基金National Natural Science Foundation of China(11974063,61904023)Key Program Science Foundation of Natural Science Foundation of Chongqing(cstc2020jcyj-jqX0028)Chongqing Special Postdoctoral Science Foundation(cstc2019jcyj-54bsh0026).
文摘Owing to their outstanding optoelectronic properties,all-inorganic CsPbBr_(3) perovskite nanocrystals(NCs)are regarded as excellent materials for various optoelectronic applications.Unfortunately,their practical applications are limited by poor stability against water,heat,and polar solvents.Here,we propose a facile synthesis strategy for CsPbBr_(3)@Cs_(4)PbBr_(6) NCs via tetraoctylammonium bromide ligand induction at room temperature.The resulting CsPbBr_(3)@Cs_(4)PbBr_(6) NCs show a high photoluminescence quantum yield of 94%.In order to prevent Cs4PbBr6 from being converted back to CsPbBr_(3) NCs when exposed to water,a second coating layer of SiO2 is formed on the surface of the CsPbBr_(3)@Cs_(4)PbBr_(6) NCs by the facile hydrolysis of tetramethoxysilane.The resulting CsPbBr_(3)@Cs_(4)PbBr_(6)/SiO_(2) NCs with their double coating structure have outstanding stability against not only a polar solvent(ethanol)but also water and heat.The as-prepared CsPbBr_(3)@Cs_(4)PbBr_(6)/SiO_(2) NCs serve as green emitters in efficient white light-emitting diodes(WLEDs)with a high color rendering index(CRI)of 91 and a high power efficiency 59.87 lm W−1.Furthermore,the use of these WLEDs in visible light communication(VLC)results in a maximum rate of 44.53 Mbps,suggesting the great potential of the reported methods and materials for solid-state illumination and VLC.
文摘Fluorescent organic materials that exhibit unique aggregation-induced emission have been utilized for various applications,including white light emission(WLE).The materials typically rely on composite designs involving a mixture of compounds emitting at different wavelengths of light.To overcome the limitations offered by the design of such composite mixtures,tremendous efforts were also emphasized in developing single-molecule substrates that emit white light.The white light by either method is typically controlled by the solvent polarity,energy and charge transfer,host-vip interactions,gelation,or embedding in the polymer or organic frameworks.This article briefly reviews various molecules exhibiting aggregation-induced emission behavior and emitting white light.
基金This work was supported by the National Natural Science Foundation of China (No. 10574165, 50021202, and 90201020)the Science and Technology Ministry of China (No. 2003CB314700, 2002AA313010, and 2001CCA04400)the Education Ministry of China, the Science and Technology Department of Guangdong Province, the Education Department of Guangdong Province, and the Science and Technology Department of Guangzhou City. The authors also thank Engineer Yanfa Liu for experimental assistance.
文摘Cubic silicon carbide （SIC） nanowires are synthesized in a catalyst-assisted process. The nanowires with diameter of ～ 40 nm exhibit strong blue light emission at room temperature under ultraviolet （UV） femtosecond laser excitation. The photon energy of peak emission is higher than the energy bandgap of cubic SiC which shows involvement of quantum confinement effect. The ultrafast fluorescence is deconvoluted by Monte-Carlo method. The results show two ultrafast decay processes whose lifetimes are about 26 and 567 ps respectively. The mechanisms of such ultrafast processes are discussed.
基金a foundation from China Taipei under Grant No. NSC99-2221-E-151-062
文摘γ-LiAlO2 phosphor was synthesized using the cellulose-citric acid sol-gel method, and its light emission and energy transfer properties were investigated. Excitation and emission spectrum analysis revealed a decrease in intensity of the spectrum as the amount of Mn2＋ doping increased. Blasse＇s equation determined the maximum distance for energy transfer between Mn2＋ ions as 4.3142 nm. Dexter＇s theory verifies that the mechanism of energy transfer between Mn2＋ ions conforms to an electric dipole and electric quadrupole interaction.
