最新刊期
卷 44 ， 期 11 ， 2023
- 摘要：Zinc oxide（ZnO） is commonly used in high-performance quantum dot light-emitting diodes（QLEDs） as electron-transport layers due to its excellent electrical properties. However， due to high electron mobility of the ZnO layer， excessive electrons are injected into the device， which leads to imbalanced charge carriers inside the devices and low efficiency. In addition， the contact between ZnO and the electrode is easily affected by the external environment （water and oxygen）， particularly for the inverted QLEDs， which dramatically affects the storage stability of devices. To solve the above problems， we use MoO3/ZnO as charge-generation layer （CGL） to prepare inverted QLEDs. This structure reduces carrier imbalance and increases the maximum current efficiency of the device from 12.8 cd/A to 15.7 cd/A. In addition， the influence of cathodes on the device performance is highly reduced in the CGL based QLEDs because the electrons are generated in the CGL， rather than being injected from the cathode. As a result， the storage stability of devices is greatly improved.关键词：charge-generation layer;charge storage;overshoot;transient electroluminescence
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发布时间：2023-11-27
Cover Story
- 摘要：With the rapid advancement of high-power LED and laser lighting technology， the research on phosphors is frequently involved with the packaging technology， optical design， modularization， and photothermal integration. For this reason， the material design and fabrication that are based on photometric parameters are getting more and more important. Therefore， a systematic understanding of the definition and characterization principles of relevant photometric parameters can facilitate the design and development of phosphor materials. This work aims to provide a concise introduction to the fundamental concepts of photometry for researchers in phosphor materials. Key parameters including luminous intensity， luminous exitance， luminance， and illuminance were introduced and discussed. Furthermore， the characterization methods and principles that are based on research cases were discussed. Finally， the research strategy based on the photometric parameters is prospected， providing new ideas for future study on phosphors.关键词：phosphors;solid-state lighting;photometry;laser lighting
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发布时间：2023-11-27
Views on Basic Knowledge of Luminescence
- 摘要：In recent years， white LED has become the mainstream lighting in the market due to its advantages of energy conservation， environmental protection， and long life-time. High performance red phosphor is an important material for improving the color rendering performance of white LED. Mn4+-activated oxyfluoride red phosphors have become a research hot spot due to their excellent luminescent properties and high stability of oxides. In this paper， a variety of red oxyfluoride phosphors using Mn4+ as an activator are reviewed. From the perspective of crystal field theory and thermal quenching mechanism， the relationship between the crystal structure of each phosphor and its luminescent properties is classified and detailed， in order to provide theoretical guidance for improving the luminescent properties of Mn4+-activated oxyfluoride phosphors. Finally， the advantages and disadvantages of Mn4+ activated oxyfluoride red phosphors and the existing problems in the research are summarized， and the future development trend is prospected.关键词：luminescent material;Mn4+;oxyfluoride;red-emitting phosphor;white LED
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发布时间：2023-11-27 - 摘要：Because of the excellent scintillation performance， halide scintillation crystals with elpasolite structure doped with Ce3+ have been attracted wide attention. In this paper， high-quality Ce3+ doped Cs2LiLa（Br，Cl）6 scintillation crystal with 1-inch size has been prepared successfully by Bridgman method. The crystal structure and composition of Cs2LiLa（Br，Cl）6∶Ce crystals were analyzed by X-ray diffraction， EDS， and X-ray photoelectron spectroscopy. The results show that the Cl- was successfully introduced into the matrix material and the crystal structure was unchanged. The photoluminescence spectra， X-ray excited emission spectra， and ultraviolet fluorescence decay results show that Cl- doping did not have a significant effect on luminescence center. It still has a fast decay time of 28 ns. The energy spectra of the crystal were measured under 137Cs@662 keV gamma source and 252Cf source. It was found that the crystal had excellent energy resolution （4.2%@662 keV） and neutron discrimination performance （FOM value is 1.9）， which had great application prospects in the field of nuclear radiation detection.关键词：Cs2LiLa（Br，Cl）6∶Ce;scintillation crystal;Bridgman method;Neutron/gamma discrimination
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发布时间：2023-11-27 -
Photo-stimulated Long Afterglow of SrAl2O4∶Eu2+,Dy3+,Tm3+ and Its Anti-counterfeit Applications 增强出版
摘要：The advancement of anti-counterfeiting technology is closely linked to national security and social stability， making it significantly important in today's society， particularly in the realm of information security. Optical storage fluorescent materials offer significant advantages in the field of anti-counterfeiting with the characteristics of low cost， high resolution and fast response speed. Unfortunately， the practical application of these materials is limited by the single anti-counterfeiting mode of the corresponding phosphor and the requirement for specific excitation wavelengths. Among various long afterglow phosphors， SrAl2O4∶Eu2+，Dy3+（SAO∶Eu2+，Dy3+） stands out as the most successful one in low-light situations， luminous paint， road signs， and other applications. The long afterglow effect of SAO∶Eu2+，Dy3+ is attributed to the release of the captured carriers by thermal disturbance at room temperature， and this phenomenon depends on the number and concentration of effective traps. It implies that constructing the trap structure of the corresponding phosphor could effectively regulate the relevant optical storage performance. In this study， the introduction of Tm3+ ions into the SAO∶Eu2+，Dy3+ optical storage fluorescent material is employed to regulate the trap density and structure. This adjustment can simultaneously reduce the trap density and form a rich deep defect structure， thereby significantly impacting the storage and release of the captured carriers. By employing near-infrared laser diode excitation， the carriers released from deep traps can be captured by the shallow traps， performing photo-stimulated properties， and the subsequently long afterglow luminescence after the removal of the excitation. Consequently， a temperature-dependent multi-mode anti-counterfeiting approach is explored to realize binary coding. This work demonstrates the application of dynamic anti-counterfeiting and optical information storage， expanding the practical application of SAO∶Eu2+，Dy3+ phosphor in the field of information security.关键词：photo-stimulated luminescence;long afterglow;Optical storage;Photo-stimulated long afterglow- 373
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发布时间：2023-11-27 - 摘要：The phosphors Sr6Lu2-2xAl4O15∶xTb3+ were synthesized through the solid-state reaction technique. The structure， photoluminescence properties and concentration quenching mechanisms were researched. The dependence of photoluminescence intensities on Tb3+ concentration was studied. Upon excitation with UV excitation， when the doping concentration x=0.01， the strongest peak located around 381 nm， which arise from 5D3-7F6 transition of Tb3+； when the doping concentration x=0.15， the strongest peak located around 545 nm， which arise from 5D4-7F5 transition of Tb3+. The luminescence color changes from blue to yellowish green by adjusting the doping concentration of Tb3+. The concentration quenching mechanisms of Sr6Lu2-2xAl4O15∶xTb3+ were studied. The lifetime， thermal stability and quantum efficiency were measured. The Sr6Lu2-2xAl4O15∶xTb3+ phosphor is a novel color-tunable phosphor.关键词：phosphors;photoluminescence;color-tunable;Tb3+ doped
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发布时间：2023-11-27 - 摘要：Phase transition is an effective way to regulate performance of materials and has been wildly applied in dielectric， photo-electricity and photoluminescence fields. Here， we report the hydrothermal synthesis of unknown phase CsAgCl2 and the phase transition of CsAgCl2 from unknown phase to orthogonal phase via annealing and Eu3+ doping strategies. The as-prepared Eu3+ doping CsAgCl2 exhibits high optical temperature sensitivities with the maximum relative sensitivity values of 3.63%·K-1 and 3.20%·K-1 for emission intensity mode and decay lifetime mode， respectively. These results indicate that CsAgCl2 is a promising candidate to be used as a high-sensitive optical temperature sensing material.关键词：phase transition;Optical temperature sensing;hydrothermal synthesis;CsAgCl2;Eu3+ doping
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发布时间：2023-11-27 - 摘要：In this work， a novel Yb3+ and Ho3+ co-doped Ba3In（PO4）3 up-conversion phosphor was synthesized by high temperature solid-state method， and its crystal structure， up-conversion luminescence and energy transfer mechanism were studied. Under 980 nm laser excitation， Yb3+ absorbs energy and transfers to Ho3+.In addition， the laser power has no significant effect on the luminescent color of the phosphor， and the luminescent color is mainly concentrated in the orange-red region （0.543， 0.452）. The fluorescence lifetime of 0.05Yb3+ and 0.032Ho3+ doped phosphor is about 467.61 μs. The temperature-dependent photoluminescence emission spectra of the phosphor were also measured， and the absolute sensitivity （Sa） and relative sensitivity （Sr） were calculated. The results show that the phosphor has good thermal stability， and the emission intensity at 423 K remains about 81.68% of that at room temperature. The ΔE of 5S2，5F4→5I8，5F5→5I8 transitions are 0.19 eV and 0.27 eV， respectively.In addition， the maximum Sa and Sr are 0.31%·K-1 and 0.09%·K-1 （573 K）， respectively.关键词：phosphor;up-conversion luminescence;temperature sensing performance
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发布时间：2023-11-27 - 摘要：As a common group Ⅲ-Ⅴ epitaxial material， InGaAs/AlGaAs multi-quantum wells （MQWs） are commonly used in the fields of semiconductor lasers and solar cells. However， the segregation of indium atoms and the poor growth quality of MQWs have not been well resolved due to the growth temperature differences between the well layer and barrier layer of quantum wells. In this paper， a gallium arsenide （GaAs） material is designed as an insertion layer （ISL） to be used in the structure of InGaAs/AlGaAs MQWs. PL and XRD， AFM tests show that the GaAs ISL guarantees more radiation recombination in the MQWs structure， preventing segregation of indium atoms. However， the introduction of GaAs ISL will induce “local states”， which will affect the luminescence properties of quantum wells. This study not only can deepen the understanding of the radiation recombination mechanism of InGaAs/AlGaAs multi-quantum wells， but also has great significance in the luminescence properties study of InGaAs/AlGaAs MQWs with GaAs ISL.关键词：InGaAs/AlGaAs multiple quantum wells;local state;insert layer;metal-organic compound gas phase epitaxy （MOCVD）
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发布时间：2023-11-27 - 摘要：A deep-ultraviolet Al0.38Ga0.62N/Al0.55Ga0.45N multiple quantum well （MQW） structure was grown on a c-plane sapphire substrate using magnetron sputtering and metal organic chemical vapor deposition （MOCVD） methods， while the excitation density and temperature dependences of its photoluminescence （PL） spectrum were measured in the wide excitation density （0.1-500 kW/cm2） and temperature （6-300 K） ranges. The excitation density-dependent peak energies and line widths of the PL peak PW from the MQWs measured at the low temperature of 6 K show that， within the low excitation density range （≤ 10 kW/cm2）， the PW line width remains almost constant， while its peak energy remains almost constant first （≤ 0.5 kW/cm2） and then gradually increases with increasing the excitation density， indicating that the excitation density-dependent emission process of the MQWs is dominated first by the combined effect of the scattering effect of high-energy （shallow）-localized carriers and filling effect of low-energy （deep）-localized states， and then by the combined effect of the filling effect of medium-energy （medium-depth）- localized states and Coulomb screening effect of free carriers. However， within the high excitation density range （>10 kW/cm2）， both the PW peak line width and peak energy increase significantly， indicating that the excitation density-dependent emission process of the MQWs is dominated by the filling effect of high-energy-localized states. On the other hand， the temperature-dependent peak energies and line widths of the PW peak measured at the low excitation density of 0.1 kW/cm2 show that， within the low temperature range （≤ 140 K）， the PW line width remains almost constant， while its peak energy monotonically decreases， indicating that the temperature-dependent emission process of the MQWs may be dominated by the combined effect of the relaxation of high-energy-localized carriers and thermal excitation of low-energy-localized carriers； within the high temperature range （>140 K）， PW peak line width increases significantly， while its peak energy blue shifts significantly relative to Varshni curve， indicating that the temperature-dependent emission process of the MQWs is dominated by the thermal excitation of localized carriers since the relaxation of the localized carriers is gradually suppressed with increasing the temperature. The above analysis results show the strong inhomogeneity in the depths of the localized states and the localized character of the carrier recombination in the AlGaN-based MQWs due to the significant fluctuations of well widths. This conclusion is also supported by the measurement of temperature dependent-integrated PL intensity （Arrhenius plot）， because this measurement result has shown that the deep-ultraviolet AlGaN-based MQW structure has two non-radiative recombination channels with different activation energies.关键词：deep-ultraviolet LED;AlGaN multiple quantum well;photoluminescence;carrier localization effect
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发布时间：2023-11-27 - 摘要：Element doping plays an important role in regulating multicolor luminescence of the carbon dots. However， it is difficult to realize the tunable fluorescence emission of carbon dots in solid state due to serious aggregation induced quenching effect （AIQ） and complicated preparation process. Herein， a kind of nitrogen and boron elements co-doped solid-state fluorescent carbon dots was synthesized by microwave reaction using phloroglucinol as carbon source， boric acid as boron dopant and urea as nitrogen dopant. With the change of nitrogen and boron elements content， the luminescent color of the obtained solid-state carbon dots undergoes variations from yellow， green to blue. After the characterization， it was found that the doping of nitrogen and boron elements formed different structures and new functional groups on the surface of the carbon dots， in which the synergistic effect of graphitic nitrogen， N—C and B—O/B—N bonds led to a blue-shift change of luminescent colors and the increasing fluorescence quantum yields （FLQYs） with the increasing contents of nitrogen and boron dopants in these solid-state carbon dots. In addition， given that these solid-state carbon dots materials exhibited excellent multicolor luminescence properties， yellow， green and blue solid-state fluorescent carbon dots with the best luminescence performance after optimizing fabricated WLED devices with excellent chromaticity indexes. The warm-white light and energy-saving and efficient working characteristics in the some devices indicate that these carbon dots materials possess potential application in the field of lighting.关键词：solid-state CDots;N and B co-doping;luminescence regulation;LED
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发布时间：2023-11-27 - 摘要：The carbon quantum dots（CQDs） containing different N， O contents were prepared by using solvothermal reaction， and the CQDs/OSTE composites were obtained quickly through cross-linking and curing the CQDs with the off-stoichiometric thiol-ene （OSTE） polymer via the reaction of “click” chemistry. It is found the fluorescence quantum yield（QY）of O-CQDs and N，O-CQDs were increased to 16.5% and 17.6%， respectively. Compared with their QYs（2.6% and 4.5%）in the liquid environment， the enhancement of about 6 and 4 times was achieved， respectively. By analyzing the changes of microstructure and optical properties of CQDs materials before and after curing， we suggested that the enhanced PL QY might originate mainly from the reduction of the oxygen-related non-radiative recombination center， the suppression of the non-radiative transition probability and the synergistic effect of N and S. Our results provide a convenient and efficient method for solid state transformation， surface functionalization and fluorescence enhancement of CQDs， which will promote the application of CQDs in light-emitting diodes， lasers and luminescent solar concentrators.关键词：carbon quantum dots;off-stoichiometric thiol-ene polymer;cross-linking enhanced emission;Surface state;luminescence center related to oxygen
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发布时间：2023-11-27 - 摘要：Due to the existence of aggregation-caused quenching （ACQ） effect， the application of carbon dots （CDs） in the solid state field is greatly limited. Herein， a new class of nitrogen/sulfur-doped CDs （G-CDs） with high fluorescence quantum yield （PLQY） and AIE effect are obtained with an eco-friendly， low-cost one-pot solvothermal method， and the structure and properties were analyzed and characterized. G-CDs exhibit blue emission （λ=400 nm） in organic solvents while after adding water， because of AIE effect. G-CDs in the aggregated state manifested as green emission， and the PLQY of the powder was measured to be 48.6%. With the increase of water concentration， the aggregation fluorescence emission of G-CDs was red-shifted， which confirmed the AIE characteristics of CDs. Based on the unique emission fluorescence and AIE effect， G-CDs have important potential applications in information encryption， ink printing and luminescent lighting.关键词：carbon dots;aggregation-caused quenching;aggregation-induced emission;anti-counterfeiting applications
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发布时间：2023-11-27
Synthesis and Properties of Materials
- 摘要：With the continuous growth of global data traffic， silicon-based photonic integrated circuits have become an up-and-coming solution in the field of high-performance intra-chip/inter-chip optical communications. However， due to silicon's extremely low intrinsic luminescence efficiency， on-chip light sources have become the most challenging components in photonic integrated circuits. To address the lack of native light sources， silicon-integrated Ⅲ-Ⅴ semiconductor lasers have been extensively studied， which offer superior optical and electrical performance. Notably， using quantum dots as the gain medium in Ⅲ-Ⅴ semiconductor lasers has garnered much attention due to several advantages， such as high tolerance to crystal defects， high temperature insensitivity， low threshold current density and low reflection sensitivity， etc. Using quantum dots in the laser gain region brings many improvements in photonic integration compared to quantum wells. The gain bandwidth can be designed to be optimized as needed and enable lasing over the entire near-infrared range. The large energy level separation between quantum states and the surrounding material gives them excellent high-temperature performance and sub-picosecond timescale gain recovery. This paper provides a comprehensive review of the latest research progress on silicon-based Ⅲ-Ⅴ semiconductor quantum dot lasers from various perspectives， including quantum dot materials and quantum dot lasers based on wafer bonding technology， flip-chip bonding technology， and direct epitaxial growth technology， and discusses their prospects and challenges.关键词：Silicon photonics;On-chip quantum dot lasers;Photonic integration
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发布时间：2023-11-27 - 摘要：We report a compact， high-efficiency， and high-power 2 μm rod-type Tm∶YAG laser. By optimizing the design of the threefold laser diode （LD） side-pumped laser module structure， the pump power density inside the crystal rod was increased. The laser resonator adopted a flat-flat cavity configuration， incorporating a single laser module， with a geometric cavity length of 88 mm and the complete laser structure was simple and compact with small footprint. The laser module was cooled by a water chiller， under a crystal cooling temperature of 12 ℃， we obtained a maximum output power of 119 W at a wavelength of 2.02 μm， with an optical-to-optical efficiency of 19.6% and a slope efficiency of 32.7%. The laser can operate stably for 2 hours at maximum output power with power fluctuations below 1%， and no water condensation was observed on the crystal end faces and optical element surfaces. The measured beam quality factors in the x and y directions were 21.01 and 21.68， respectively. This compact， reliable， and efficient hundred-watt level 2 μm laser is of great significance for applications in medical and scientific research.关键词：lasers;Tm∶YAG;rod crystal;LD side-pumping;2 μm;compact structure
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发布时间：2023-11-27 - 摘要：The effects of defects on the performance of all inorganic perovskite solar cells was studied using a one-dimensional solar cell simulation software SCAPS. It is found that in the device ITO/SnO2/CsPbI3/CuI/Au， the density of the defects at the CuI/CsPbI3 interface and in the CsPbI3 photoactive layer has dramatically influence on the performance of the device. With the increase of the defect density， the open-circuit voltage， short-circuit current， filling factor， and power conversion efficiency of the device all decrease， especially when the defect density exceeds 1015 cm-3. On the contrary， the defects at the CsPbI3/SnO2 interface have almost no effect on device performance. By optimizing the defect density of the device， the thickness and doping concentration of the photoactive layer， a power conversion efficiency higher than 20% can be obtained in the all inorganic perovskite solar cells.关键词：perovskite solar cell;all inorganic;defect;simulation
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发布时间：2023-11-27
Device Fabrication and Physics
- 摘要：Multiphoton imaging is an advanced imaging technique for its visible signal output with zero background. However， the required high pump threshold and poor photostability of traditional multiphoton probes hinder their biological applications. Rare earth doped upconverting nanoparticles become an important type of multiphoton probe because of the featured lower excitation density and better stability. Due to the development of imaging techniques， the study of ensemble upconverting nanoparticles is transiting toward singles. The study of single upconverting nanoparticles not only eliminates the interference of environmental factors， but also provides a bench of different theoretical conclusions against ensemble studies. Single particle imaging platform is more comparable with the practical biological imaging platform， thus designing more efficient upconverting nanoparticles and understanding physical mechanism at single particle level are readily for practical applications. Here， based on the multiphoton luminescent mechanism and materials， recent research achievements and application progress of single upconverting nanoparticles are reviewed. Finally， the future development and applications of single upconverting nanoparticles are prospected.关键词：multiphoton probe;upconverting nanoparticles;single-particle imaging;biological application
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发布时间：2023-11-27 -
Recent Progress in Small-molecule Fuorescent Probes for
in situ Imaging and Detection of Enzyme 增强出版摘要：Enzyme widely exists in various life activities. Some diseases are closely related to abnormal expression of active enzymes. Accurate detection of enzyme expression levels and in situ imaging provide a powerful basis for diagnosis and treatment of related diseases. Up to now， a large number of detection technologies have been developed， among which the fluorescent technology represented by small-molecule fluorescent probes has advantages such as non-invasive， high sensitivity， low detection limit， fast response time and good biocompatibility. It is favored in the detection of biological enzyme. However， as small-molecule fluorescent probes are used for detection， they tend to diffuse at the active sites of enzyme， resulting in poor spatial and temporal resolution of the probes. Therefore， in order to improve the spatial and temporal resolution of imaging detection and reduce background interference and false positives， the design of in situ imaging has been proposed， which has become one of the research focuses of optical imaging. At present， researchers have reported that a variety of small-molecular fluorescent probes have been used in the design of enzyme in situ imaging and achieved remarkable results. This review will introduce the design strategy of small-molecular fluorescent probes for enzyme detection and the research progress in situ imaging， hoping to provide some inspirations for researchers in this field.关键词：in situ imaging;small-molecule fluorescent probes;enzyme;recent progress- 226
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发布时间：2023-11-27 - 摘要：In this paper， a polymer-based rare earth hybrid probe functionalized by Eu3+ was designed and synthesized. The coordination reaction between benzoyl trifluoroacetone （BFA） and lanthanide Eu3+ was used to obtain the complex Eu（BFA）3， which was further prepared by polymerization with MMA monomer to obtain polymer hybrid probe Eu（BFA）3@PMMA. The structure and fluorescence properties of Eu（BFA）3@PMMA were investigated in detail. It is also used in the sensor detection of tumor marker sialic acid （SA）. The results showed that SA can produce a significant quenching effect on the fluorescence of Eu（BFA）3@PMMA. In addition， fluorescence properties contrast experiments at excitation wavelength of 325 nm showed that Eu（BFA）3@PMMA had strong selectivity and anti-interference ability for SA， and the detection limit was low.关键词：lanthanide complexes;hybrid probes;sialic acid;fluorescence sensing
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发布时间：2023-11-27
Luminescence Applications and Interdisciplinary Fields
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