最新刊期
卷 44 ， 期 5 ， 2023
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Colloidal Quantum Dot Electroluminescent Diodes for Display Applications: Progress and Challenges 增强出版
摘要：Colloidal quantum dots （QDs） have the advantages of easy tunable wavelength， narrow emission， high efficiency， and so on. Corresponding electroluminescent （EL） QD light-emitting diodes （QLED） have the advantages of solution treatment， simple and low cost manufacturing process， which is beneficial to realize the wide color gamut， high contrast， large area and flexible display. However， there are still challenges in device performance and patterning technology for QLED-based display applications. With the progress of material and device engineering， the research of QLED display has made further progress. This paper first introduces the development of QDs and QLED in display application， then indicates the challenge and research progress of QLED in display application.关键词：colloidal quantum dots;electroluminescent diodes;display technology- 790
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发布时间：2023-06-15
Cover Story
- 摘要：In the field of solid-state lighting， phosphors for laser lighting have been becoming a hotspot of the current research. With extensive research and fruitful results appeared， researchers have improved a deeper understanding of phosphors for laser lighting. However， current design and investigation of phosphors for laser lighting are still highly influenced by wLED industry， resulting in that plenty of theoretically “good” phosphors are actually not suitable for laser lighting applications. The aim of the present study is to clarify the key properties of phosphors for laser lighting from an application perspective. Firstly， the difference between the phosphors for laser lighting and for high-power wLED is discussed. Secondly， the misunderstandings in the design and characterization of current phosphors are pointed out. Thirdly， the novel design principle and the related mechanisms are summarized. Lastly， the design and packaging schemes of some commercial phosphors are introduced， several promising material design schemes are presented， and the development trend of related research is prospected.关键词：laser lighting;solid-state lighting;phosphor
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发布时间：2023-06-15
Expert Perspectives
- 摘要：X-ray detection plays an essential role in areas such as medical imaging， determination of specific crystal structures， and radio astronomy. However， traditional materials used in the field of X-ray detection， such as silicon and cadmium antimonide， suffer from complex fabrication processes， excessive cost and low sensitivity to X-rays， which severely limit the development of the field. As a hot topic in recent years， lead halide perovskites have shown excellent performance in the field of X-ray detection due to their large atomic numbers and elevated absorption coefficients. While the perovskite material system is a huge family， different components of perovskite materials have their advantages and disadvantages， and even the same component of perovskite material can have different properties depending on different parameters such as crystallization. In this paper， we review recent achievements in direct-conversion perovskite X-ray detectors from the perspective of perovskite material regulation and provide an outlook on future developments in perovskite X-ray detection.关键词：Perovskite;material regulation;direct type;X ray detection
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发布时间：2023-06-15
Invited Review
- 摘要：The 2Eg→4A2g transition of Mn4+ ion is parity- and spin-forbidden. For Mn4+-activated phosphors， it is of both scientific and industrial interest to obtain intense zero phonon line （ZPL） emission of this transition. In this review， the synthesis， crystal structure and luminescence property of Mn4+-doped oxyfluoride phosphors with intense ZPL were summarized. Some rules have been found. The cations forming octahedron in oxyfluoride phosphors with intense ZPL include Nb5+/Mo6+/Ta5+/W6+， which have higher valence state than Mn4+ and are heterovalent for Mn4+ substitution. Distortion of octahedron in the oxyfluoride host lattice is necessary to obtain intense ZPL. The ZPL can be more intense than the Stokes ν6 phonon sideband emission in some oxyfluorides， while in some others， it can be lower than the ν6 emission. The wavelength of the ZPL in typical oxyfluorides is ranging from 619 nm to 628 nm， close to the luminescence energy of Mn4+ in typical fluorides. The ZPL/ν6（Stokes） intensity ratio is not only dependent on the chemical composition of the phosphor， but also varies with the preparation method for a specific phosphor.关键词：Mn4+;red-emitting phosphor;zero phonon line;oxyfluoride
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发布时间：2023-06-15
Views on Basic Knowledge of Luminescence
- 摘要：Lead halide perovskites have a wide range of application prospects in optoelectronic devices， including solar cells， light-emitting diodes（LEDs）， photodetectors， lasers， etc. However， the poor material stability and the inherent toxicity of lead have hindered its further commercialization. Therefore， all-inorganic lead-free halide perovskites and their derivatives have become one of the research hotspots. Cs3Cu2I5 is a new all-inorganic lead-free halide perovskite derivative， which allows the possibility to be applied in a variety of fields due to its nontoxicity， excellent optical properties and good stability under ambient conditions. This article introduces the various synthesis methods， physical properties and the applications in LEDs， ultraviolet photodetectors， scintillators and other fields of Cs3Cu2I5. In addition， the challenges and prospects of Cs3Cu2I5 in optoelectronic fields are presented.关键词：perovskite;Cs3Cu2I5;self-trapped excitions;light⁃emitting diode（LED）;photodetector
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发布时间：2023-06-15 - 摘要：Along with the development of versatile trichromatic phosphors， exploring novel narrow-band blue-emitting phosphors has been an ongoing focus in liquid crystal display backlighting to satisfy the high-quality display demands. Herein， an intriguing narrow-band blue-emitting phosphor K2BaPO4F∶Eu2+ belonging to the perovskite-type structural prototype is synthesized via the solid-state reaction. Structural analysis indicates that the ［FK4Ba2］ octahedra is interlinked with each other by sharing Ba and K atoms to build a three-dimensional network together with ［PO4］ tetrahedra in the cavities. Rietveld refinement analysis shows that the Eu2+ ions reside in both Ba2+ and K+ sites to form the ［Eu（1）O8F2］ and ［Eu（2）O6F2］ polyhedra， which totally induce an intense blue emission peaking at 432 nm with a narrow full width at half-maximum of 43 nm， theoretically verified by the dipole-dipole interaction in the Eu（1）→Eu（2） energy transfer process. The electronic structure of K2BaPO4F matrix is studied by the first-principle calculation on the basis of the density functional theory， demonstrating that it has a large indirect band of 5.035 eV. The K2BaPO4F∶Eu2+ phosphor exhibits a suitable thermal stability （I493 K/I293 K=64%） and possesses the satisfactory internal/external quantum efficiency of 72.8%/46.4%， which although is inferior to that of the representative BaMgAl10O17∶Eu2+， K1.6Al11O17+δ∶Eu2+ and Na3Sc2（PO4）3∶Eu2+ phosphors， yet surpasses some other recently reported blue-emitting phosphors. Consequently， the present work not only demonstrates the potential of K2BaPO4F∶Eu2+ phosphor as a new narrow-band blue-emitting phosphor candidate， but provides the possibility for exploring the novel phosphors inspired by the mineral-type structural prototypes.关键词：perovskite-type structure;K2BaPO4F∶Eu2+;energy transfer;photoluminescence
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发布时间：2023-06-15 - 摘要：One of the more critical attributes of inorganic phosphors is the thermal quenching properties. In this study， we attempt to improve the photoluminescence and thermal quenching behavior by cation substitution. The optical， structural property， the thermal stability， and lifetime decay properties of phosphors were investigated. The results indicate that Sr substitution of Ba in Li3Cs2Ba2-xSrxB3P6O24∶Eu2+ system could not only improve the luminous efficiency but also achieve better thermal stability at high temperature. This new series of blue luminescent materials have potential applications in LED applications. More importantly， we demonstrate a strategy to develop highly efficient， thermally stable phosphors.关键词：phosphor;Eu2+;thermal quenching;cation substitution
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发布时间：2023-06-15 - 摘要：Er3+-doped fluortellurite glass microspheres composed of 60TeO2-10GeO2-20BaF2-9Y2O3-1Er2O3 were prepared by high temperature floating-powder melting method， and their quality factor （Q）， near-infrared laser performance and temperature sensing were studied in detail. The results show that the Q factor of the microsphere cavity can be as high as ~106. Under excitation of a 980 nm LD， 1 607 nm laser output with the threshold of 54 μW and optical conversion efficiency of 0.050% was realized in the microsphere with the diameter of 44.58 μm. By investigating the influence of microsphere diameter on the laser performance， it can be obtained that with the decrease of the microsphere diameter， the laser threshold gradually decreases and the optical conversion efficiency gradually increases. This is mainly attributed to the higher energy density and stronger light-matter interaction of the smaller microsphere cavity. In addition， the temperature sensing property of the microsphere cavity was investigated， yielding a temperature sensitivity of 14 pm/℃. These results indicate that the prepared Er3+-doped fluortellurite glass microsphere cavity may find potential applications in low threshold lasers and high-sensitivity temperature sensors.关键词：glass microspheres;Er3+-doped;fluortellurite;temperature sensing
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发布时间：2023-06-15 - 摘要：Glass ceramics embedded with only one kind of nanocrystals are usually cannot meet the requirements of multi-color， multi-mode and ultra-wideband luminescence applications due to the limitation of single crystal field environment. It is thus of significance to develop dual-phase nanocrystal-based glass ceramics for expanding the application field of this kind of functional materials. In this paper， an aluminosilicate glass ceramic containing α-Zn2SiO4 and β-Zn2SiO4 nanocrystals was successfully prepared by a melt quenching technique. The transition from single-phase to dual-phase nanocrystals can be achieved by varying Al2O3 content and heat treatment temperature. The obtained glass ceramics exhibit tunable single-band （~580 nm） and continuous dual-mode （~530/580 nm） emission under the excitation of 285 nm， and the luminescence intensity varies with the concentration of Mn2+ and heat treatment temperature， resulting in a tunable emissive color from orange to yellowish. The related luminescence mechanism was explained by combining with the structure of nanocrystals and spectral data. This research may be of reference value for the preparation of dual-phase glass ceramics and exploration of broadband light source.关键词：glass-ceramics;dual-phase nanocrystals;Mn2+ ions;broadband luminescence
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发布时间：2023-06-15 - 摘要：Organic luminogens can be divided roughly into two main classes： aggregation-caused quenching （ACQ） and aggregation-induced emission （AIE） molecules， which are highly emissive only in single molecular and aggregated state， respectively. In this work， we synthesized a liquid crystalline molecule （MS⁃12） with high emission efficiency both in solution and solid state and studied its liquid crystalline and photophysical properties.MS⁃12 consists of a long rod-like core ended by two Percec-type dendrons. The rigid core is composed of cyanostilbene and diphenylacetylene units， featuring a D-A-π-A-D emitter. It renders a hexagonal columnar liquid crystalline phase in bulk state， with four molecules in each monomolecular-thick（～0.44 nm） hexagonal unit cell. In dilute solution， it behaves like a ACQ molecule with a quantum yield（QY） up to 78.1% in THF. It shows a strong AIE character in condensed state， with a QY of 59.6% in bulk liquid crystalline state. This work provides a general strategy to multi-state emissive organic luminogens， those in particular with liquid crystalline properties.关键词：aggregation-induced emission（AIE）;aggregation-caused quenching（ACQ）;multi-state emissive;liquid crystal
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发布时间：2023-06-15
Synthesis and Properties of Materials
- 摘要：The CsPbBr3 and CsPbBrI2 all inorganic perovskite transport layer and emission layer were vapor deposited on the PEDOT∶PSS hole transport layer. The performance of the all inorganic red light emitting diodes（PeLEDs） based on CsPbBrI2 luminescence was significantly improved by using PEDOT∶PSS/CsPbBr3 as the double hole transport layers.Compared with the traditional PeLEDs using PEDOT∶PSS as the hole transport layer， the enhancement ratio of luminance， current efficiency and external quantum efficiency is up to 44%， 157% and 180% respectively. This obvious performance improvement is attributed to the improvement of hole injection efficiency caused by the promoted energy level alignment for the hole transport and the suppressed exciton quenching by the negative impact of PEDOT∶PSS acidity. Meanwhile， the crystallization quality of the CsPbBrI2 emission layer grown on the CsPbBr3 layer was improved. This is a simple and effective strategy to grow transport layer and emission layer in PeLEDs by vapor deposition， which has great potential in improving the performance of vacuum-evaporated all-inorganic PeLEDs.关键词：all-inorganic perovskite light-emitting diodes;vapor deposition;CsPbBr3;hole transport layer
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发布时间：2023-06-15 - 摘要：In this paper， Ga2O3 thin film was grown on c-plane sapphire substrate by metalorganic chemical vapor deposition （MOCVD）， and then asymmetric electrodes were fabricated on the surface of Ga2O3 thin film by photolithography， lift-off， and electron beam evaporation. Pt/Au was used as the Schottky electrode， and Ti/Al/Ni/Au was used as the Ohmic electrode. In order to achieve good Ohmic contact and improve the injection efficiency of interface carriers， the corresponding annealing treatment is carried out. The relevant results show that the Pt/β-Ga2O3 Schottky photodiode has a good level of deep ultraviolet detection. At -5 V bias， the responsivity and external quantum efficiency was 3.4 A/W and 1.66×103%， respectively. The detectivity was up to 1013 Jones， indicating that it has excellent weak signal detection capability. At the same time， the responsivity and external quantum efficiency decrease with the increase of light intensity， which is due to the higher concentration of photogenerated carriers which improves the recombination probability of electron-hole pairs. In self-powered mode， the Pt/β-Ga2O3 Schottky photodiode exhibited a fast responsivity of 2.69 mA/W. In addition， the detector can still operate stably under high voltage of -100 V and +100 V， indicating that the detector has good stability against high voltage operation.关键词：Ga2O3;Schottky photodiode;UV detection;self-driven
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发布时间：2023-06-15
Device Fabrication and Physics
- 摘要：Rare-earth-doped laser glass is the key medium of fiber lasers. However， how to predict the spectroscopic properties quantitatively remains a challenge to accelerate the development of high-performance laser glass. Here we regard the nearest-neighboring congruently melting compound（CMC） as the component and structural “motif” of glass based on the phase diagram model and apply it to the Tm3+-doped binary germanate laser glass systems. The experimental properties of Tm3+-doped glassy CMCs are utilized to calculate and predict the physical and spectroscopic properties， such as density， refractive index， effective linewidth， absorption/emission cross-sections， radiation lifetime， etc.， of germanate laser glass by utilizing the leverage rule. The results illustrate that the predicted physical and spectroscopic properties are in good agreement with the experimental values， with the maximum absolute errors of less than 4.61% and 9.66%， respectively. Moreover， the phase diagram approach can capture the trends of physical and spectroscopic properties as a function of composition， including the linearly or germanate-anomaly compositional dependence， which provides an opportunity to decipher the composition-structure-property relationships of laser glass. This study is expected to shed light on the property prediction and composition design of laser glass.关键词：laser glass;spectroscopic properties;quantitative prediction;phase diagram model
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发布时间：2023-06-15
Theoretical Calculation and Spectral Analysis
- 摘要：A Ni/Au/Ni/Au transparent electrode system was deposited on the surface of p-AlGaN， and the effects of annealing temperature on the contact characteristics of Ni/Au/Ni/Au with p-AlGaN were studied by transmission line model. When the AlGaN-based deep ultraviolet LED adopted Ni/Au/Ni/Au metal system， meanwhile annealed at 600 ℃ for 3 min， the results show that p-type semiconductor material NiO can be formed in the contact interface. The metal thickness of Ni/Au/Ni/Au system was further optimized. When the Ni/Au/Ni/Au layers were thinned from 20/20/20/20 nm to 2/2/5/5 nm，with the annealing condition at 600 ℃ for 3 min， the specific contact resistivity decreased from 3.23×10-1 Ω·cm2 to 2.58×10-4 Ω·cm2. Using the above optimized Ni/Au/Ni/Au system into LED chip process， the photoelectric characteristics of the LED device can be improved drastically. The operating voltage was reduced to 5.8 V at 150 mA， as the increase of the electrode transmittance， the optical output power was increased by 18.9% at the same current.关键词：UV-LED;AlGaN， NiAu;Ohmic contact
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发布时间：2023-06-15
Luminescence Industry and Technology Frontier
- 摘要：Novel low-dimensional organic-inorganic hybrid phosphors have unique optical properties and wide optoelectronic applications. Zero-dimensional organic-inorganic hybrid phosphor ［N（CH3）4］2GeF6∶Mn4+ was synthesized by a wet chemical method. By using XRD， TG-DTA， FTIR， DRS， PL， PLE， and lifetime decay， the crystal structure， thermal stability， and optical properties were systemically investigated. The result shows that narrow red emission with high color purity can be observed even at room temperature， and the emission peak locates at 630 nm. In the temperature range of 13-292 K， anti-Stokes and Stokes sidebands of Mn4+ ions show different temperature responses. The emission intensity ratio of anti-Stokes vs. Stokes sidebands can be used for temperature sensing， with a maximum absolute sensitivity of 0.002 1 K-1 and relative sensitivity of 2.11%·K-1. Moreover， the lifetime of Mn4+ ions can also be used for temperature sensing with a maximum relative sensitivity of 0.44%·K-1， demonstrating its potential application in dual-mode optical thermometry.关键词：zero-dimensional luminescent material;Mn4+;temperature sensing
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发布时间：2023-06-15 - 摘要：Aniline sensing is of great societal implications， as aniline is a crucial chemical raw material but with high toxicity， processing with huge impacts on environment safety and human health. Herein， a novel cyanostilbene derivative （CN-DBE） was designed and synthesized as selective fluorescent probe material for aniline detection. Its aggregation-induced emission property， sensing property and detection mechanism were elucidated by photoluminescence spectra and numerical simulation. The results reveal that CN-DBE possesses high selectivity， quantitative and rapid detection ability to aniline due to the electron transfer mechanism. Moreover， the CN-DBE compound can also enable the fabrication of test strips， which provide a cheap and simple way to detect aniline leakage.关键词：fluorescence sensor;cyanostilbene;aggregation-induced emission;aniline;rapid detection;photo⁃induced electron transfer
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发布时间：2023-06-15 - 摘要：The preparation of purple-emissive carbon dots （P-CDs） usually accompanies the disadvantages of complicated preparation， low quantum yield （QY） and low fluorescence intensity. Herein， we used o-phenylenediamine （OPD） and m-phenylenediamine （MPD） as nitrogen sources and citric acid （CA） as carbon source to prepare P-CDs. Only using simple one-step hydrothermal method under a low experimental temperature of 120 ℃， we successfully obtained highly luminescent P-CDs with absolute QY of 5.3%. The results of XPS and FT-IR revealed that all synthesized P-CDs contained similar functional groups but with different contents. The fluorescence intensity of P-CDs could be effectively regulated by the amount ratio of OPD to MPD. The resulting P-CDs also possessed considerable photostability and salt stability. Notably， the fluorescence color of P-CDs remarkably transformed into green as the pH being in the range of 1-3 or 10-13. The aforementioned unique pH-dependent fluorescence chromic behaviors ensured the potential application in the optical pH sensing.关键词：High luminescence;Purple-emissive carbon dots;Optical pH sensing
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发布时间：2023-06-15
Luminescence Applications and Interdisciplinary Fields
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