最新刊期
卷 45 ， 期 4 ， 2024
- “最新研究发现，维生素C作为多功能添加剂，可显著提升纯红光铅基钙钛矿发光二极管的发光性能，有望推动其在显示领域的应用。”摘要：Lead halide perovskite light-emitting diodes with tunable light emission， high luminance， high external quantum efficiency， wide color gamut， low cost and solution processable are promising candidates for solid-state lighting， ultrahigh-definition displays and optical communications. However， lead halide perovskites are toxic and harmful to both the human body and environment， which are therefore not in line with the concept of sustainable development. Two-dimensional phenylethylammonium tin-iodide （PEA2SnI4） perovskites with pure red emission are expected to become next-generation red light-emitting materials for displays due to their advantages of ultrahigh color purity， ultrawide color gamut （close to the Rec.2020 standard）， and environmental friendliness. However， the faster growth rate of tin-based perovskite films compared to lead-based perovskites results in poorer quality films， and Sn2+ ions are easily oxidized to Sn4+， resulting in nonradiative composites. The electroluminescence（EL） performance of pure red PeLEDs prepared based on PEA2SnI4 is poor and lags far behind that of Pb-based PeLED devices. Here， we demonstrate that vitamin C is an effective multifunctional additive， which reduces the crystallization of the perovskite and improves the quality of the film by interacting with PEA2SnI4. Vitamin C can also significantly reduce the trap density and the nonradiative recombination rate by preventing the oxidation of Sn2+ to Sn4+. After addition of the vitamin C， the PeLEDs exhibit enhanced EL properties， with the maximum brightness and the maximum external quantum efficiency increasing from 67.6 cd/m2 and 0.2% to 513.6 cd/m2 and 0.68%， respectively. This work indicates the red-emitting PeLEDs based on PEA2SnI4 have great potential applications in the field of displays， and also provides ideas for the preparation of highly efficient tin-based perovskite materials.关键词：pure-red emitting;perovskite;electroluminescence;light-emitting diode
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发布时间：2024-04-26
Cover Story
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Research Progress on Synthesis, Regulation and Applications of Long-wavelength Emission Carbon Dots 增强出版 AI导读
“最新研究进展显示，长波长发射碳点在生物医学、光电子和光学器件等领域具有重要应用潜力。通过选择特定碳源和调控光学性质，可设计和合成具有深组织穿透、低自荧光和长荧光寿命等特性的碳点。”摘要：In recent years， with the development of carbon dots in terms of synthesis routes， reaction mechanisms， and optical properties， a large amount of work has focused on carbon dots that emit long wavelengths such as infrared or near-infrared. Long wavelength refers to the red or near-infrared spectral region whose emission range is 600- 1 800 nm. Compared with short-wavelength carbon dots， they have the characteristics of deep tissue penetration， less autofluorescence， long fluorescence lifetime and less light damage， and can be further applied in the fields of biomedical treatment， optoelectronics and optical device preparation. Therefore， in-depth exploration of the design and synthesis of long-wavelength emitting carbon dots is of great significance for their development and wide application. This article reviews the research progress of long-wavelength carbon dots in recent years， and introduces how to prepare long-wavelength carbon dots from two aspects： carbon source selection and control of optical properties. For example， choose some aliphatic compounds containing more amino groups and aromatic compounds with conjugated structures. And its optical properties can be controlled through changing the effective conjugation length， surface modification， and heteroatom doping. Finally， the latest research and future challenges of long-wavelength carbon dots in some fields such as biomedicine， LED optics， encryption and anti-counterfeiting are introduced.关键词：long-wavelength emission;carbon dots;optical properties;application- 1047
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发布时间：2024-04-26
Invited Review
- 摘要：β-Ga2O3 has many advantages such as wide bandgap， high breakdown field strength， and high Baliga's figure of merit， making it an emerging semiconductor material with great potential for high-power electronic devices， gas sensors， and solar-blind ultraviolet detectors. However， the challenge of achieving p-type doping poses a major obstacle to the development of β-Ga2O3. Firstly， the advantages of β-Ga2O3 have been outlined briefly， and its structure and basic properties have been introduced as well. Secondly， the effect of the intrinsic defects of β-Ga2O3 on electrical conductivity has been discussed detailed， especially， for the oxygen vacancy. And then， the current research status of p-type doping in β-Ga2O3 has been discussed including N， Mg， Zn and other acceptor elements doping， co-doping with two elements and other methods. Additionally， the reasons for difficulty in p-type doping have been presented. Finally， this review discussed and looked forward to future developments for β-Ga2O3.关键词：β-Ga2O3;intrinsic defects;p-type doping;wide bandgap semiconductors;semiconductors
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发布时间：2024-04-26
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Luminescent Properties and X-ray Imaging Research of Zero Dimensional Metal halide （C24H20P）CuI2 增强出版 AI导读
摘要：Perovskite scintillator materials are widely used in the fields of medical CT， industrial safety and non-destructive testing. As a new generation of high-performance perovskite materials， copper-based（Ⅰ） metal halides have received widespread attention from researchers. This paper uses a simple antisolvent method to prepare a new type of copper-based scintillator （C24H20P）CuI2（C24H20P = tetraphenylphosphine）.（C24H20P）CuI2 displays broadband yellow luminescence with a high photoluminescence quantum yield （PLQY） of 45.84% and a large Stokes shift of 148 nm under blue light excitation at 414 nm. High PLQY and negligible self-absorption enable （C24H20P）CuI2 to exhibit impressive scintillation performance under X-ray excitation， with a light yield of ~21 000 photons/MeV and a detection limit as low as 0.869- 1180
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发布时间：2024-04-26 - 摘要：A series of novel Ca2MgTeO6∶Bi3+，Mn4+ phosphors were successfully prepared using the high-temperature solid-state method. The microstructure， morphology， luminescence properties， and temperature-sensitive properties were characterized. The dual emission centers with different temperature sensitivity of Ca2MgTeO6∶Bi3+，Mn4+ phosphors are derived from the 3P1 →1S0 transition of Bi3+ ions and the 2Eg→4A2g transition of Mn4+ ions， respectively. Since the luminescence centers of Bi3+ and Mn4+ ions vary with temperature， the phosphor's maximum absolute sensitivity and relative sensitivity are 0.027 K-1 and 1.83%·K-1 in the 200-500 K range， respectively. At the same time， the luminescence color of Ca2MgTeO6∶Bi3+，Mn4+ changes from orange at 200 K to purple at 500 K. The experimental results show that Ca2MgTeO6∶Bi3+，Mn4+ phosphors can be used as optical materials for temperature detection.关键词：optical temperature measurement;fluorescence intensity ratio;Bi3+;Mn4+;thermo-responsive characteristics
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发布时间：2024-04-26 - 摘要：Broadband near-infrared （NIR） light sources based on NIR phosphor-converted light-emitting diodes （NIR pc-LEDs） are desirable for NIR spectroscopy applications， while desiring thermally stable NIR phosphors has posed a great challenge. Herein， we report a comprehensive study into the synthesis， structural， and photoluminescence properties of Cr3+-activated Gd3Ga5O12 garnet phosphors with high efficiency and superior thermal stability. Upon 450 nm excitation， it produces a broadband NIR emission in the 620-1 100 nm range with a maximum at 740 nm and a FWHM of 97 nm. Remarkably， the Gd3Ga5O12∶0.12Cr3+ phosphor exhibits high internal quantum efficiency of 54.6% and outstanding thermal stability （106%@425 K）. Furthermore， spectral broadening and thermal stability enhancement are achieved by the codoping of Nd3+/Yb3+ via efficient energy migration between Cr3+ and Nd3+/Yb3+ ions. Lastly， an NIR pc-LED device fabricated using as-prepared phosphors yields a high NIR output power of 55.5 mW under 320 mA input current， demonstrating their potential application in high-power NIR pc-LEDs.关键词：Chromium;Broadband NIR;garnet structure;thermal stability;NIR pc-LEDs
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发布时间：2024-04-26 - 摘要：In this article， we investigate the method of growing LED（Light emitting diodes） epitaxy on sapphire/graphene substrates and its impact on improving optoelectronic performance. The research results indicate that sapphire/graphene samples have a smaller FWHM（Full width half maximum） compared to traditional sapphire samples， indicating that sapphire/graphene substrates have a lower dislocation density. And in Raman testing， it was shown that the sapphire/graphene sample was subjected to less compressive stress than traditional samples. In the elemental analysis， it was shown that the growth of the active region quantum well was good， and In and Ga elements were uniformly distributed in the quantum well without any mutual diffusion. The photoelectric performance test of the sample shows that the LOP（Light output power） of the sapphire/graphene sample is higher than that of the traditional sample， both at working current and saturation current， and the efficiency is improved compared to the traditional sample. In the variable temperature test， sapphire/graphene samples also showed lower thermal resistance， lower junction temperature， and smaller wavelength shift. In summary， samples grown by epitaxial growth on sapphire/graphene substrates have significantly improved the optoelectronic and heat dissipation performance of the device.关键词：sapphire/grapheme;crystal quality;efficiency drop;thermal characteristics
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发布时间：2024-04-26
Synthesis and Properties of Materials
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Improving Performance of Quantum Dot Light-emitting Diode with Self-immersed Nanoimprint-coupling 增强出版 AI导读
摘要：Colloidal quantum dot materials have been widely studied for their excellent narrow emission spectra， tunable emission wavelengths， high luminous efficiencies and excellent stability， and their simultaneous solution-processability has made quantum dot light-emitting diodes （QLEDs） widely applicable and used. However， the inherent substrate mode within the device leads to a large amount of photons in QLED devices being confined internally and not utilized. In this work， a solvent self-infiltration nanoimprinting process is developed based on the traditional nanoimprinting process while utilizing the surface binding energy of polydimethylsiloxane （PDMS） material itself， which has low pressure dependence and simplifies the traditional process flow， and based on which the micro-nanostructured patterns in three sizes of 1.3， 1， 0.5 μm with high periodicity are produced. Micro-nano-structured patterned layers of three sizes were fabricated based on which the red， green and blue QLED devices were out-coupled to realize light extraction. In this case， the brightness of the 1.3 μm micro-nanostructured coupled green QLED device reaches 715 069 cd·m-2， and the maximum external quantum efficiency （EQE） and current efficiency are enhanced to 12.5% and 57.3 cd·A-1. The individual electrical performances of the 1 μm-size-coupled blue QLED device are nearly 200% improvement. The EQE of the 0.5 μm size-coupled red QLED device is also improved from 17.3% to 20.5%. And through the angular distribution test， it is proved that the micro-nano structure does not affect the luminous intensity of QLED devices， which is still close to the Lambertian emission. The solvent self-infiltration nanoimprinting process and QLED light extraction method proposed in this work provide a simple and effective way to improve the performance of QLEDs.关键词：quantum dot light-emitting diode;nanoimprint;coupled optical properties;optical simulation- 423
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发布时间：2024-04-26 - 摘要：Currently， photodetectors with broadband-narrowband dual-mode detection modes are popular in special applications. Traditional photodetectors with dual-mode detection modes are achieved by adding different filters to the broadband photodetectors. However， complex optical components increase the manufacturing cost of photodetectors and the complexity of device integration. Based on the above problems， we prepared MAPbCl3/MAPbBr3 perovskite single crystal heterojunction through a simple solution hot pressing method， and built a photodetector with adjustable detection band based on the single crystal heterostructure. When the incident light is incident from the side of the MAPbCl3 single crystal， the device shows high responsivity（∼0.05 A·W-1） and high spectral suppression ratio（∼55） only to the visible part（400-600 nm）， and its rise time and decay time are 4.1 μs and 620 μs. When the light is incident from the side of the MAPbBr3 single crystal， the device has an obvious and continuous light response to the ultraviolet-visible part（300-600 nm）. Therefore， our proposed solution hot pressing method and single-crystal heterostructure provide an effective solution for the preparation of high-performance photodetectors with tunable detection wavelengths.关键词：photodetector;perovskite;single crystal;multi-band detection
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发布时间：2024-04-26 - 摘要：The excellent properties of diamond make it a great application potential in the field of solar blind ultraviolet detection. In this paper， heteroepitaxial diamond films were grown on （111） monocrystalline Si substrates by microwave plasma chemical vapor deposition （MPCVD） and the metal-semiconductor-metal（MSM） structure diamond solar blind UV detectors with planar interdigital graphite electrode prepared by pyrolytic photoresist method were produced. The results show that the heteroepitaxial diamond film on silicon substrate is the highly oriented polycrystalline film. The X-ray diffraction peak of the （111） diamond is 43.9°， and the full width at half maximum（FWHM） is 0.093°， while the Raman scattering peak of diamond is 1 332 cm-1 and the FWHM is 4 cm-1， indicating high crystal quality of the heteroepitaxial polycrystalline diamond film. The graphite electrodes were characterized by the optical microscopy and Raman spectroscopy. It shows that compared with the laser ablation method， the pyrolytic photoresist method simplifies the processes and reduces the cost. It is an effective method for preparing graphite electrodes on diamond films. The dark current of the detector with the graphite electrode reaches 2.07×10-8 A at 5 V bias， and the light-to-dark current ratio reaches 77 at 5 V bias. The diamond detector with the graphite electrode has excellent time response performance. The rising time is 30 ms and the falling time is 430 ms. Therefore， the diamond solar blind UV detector with the graphite electrode prepared by pyrolytic photoresist has high performance.关键词：diamond films;graphite electrodes;solar blind ultraviolet detectors
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发布时间：2024-04-26 - “最新研究进展显示，通过在萃取剂中添加乙酸胍对钙钛矿表面进行处理，可显著提升钙钛矿发光二极管的性能和稳定性。该策略有效减少了钙钛矿层表面缺陷，荧光量子产率从64%提升至79%，发光二极管最大效率达到11.66%，亮度高达1285 cd·m-2，明显优于未处理的参考器件。”摘要：Metal-halide perovskite materials have attracted much attention in recent years due to their excellent optoelectronic properties， which can be used to fabricate light-emitting layers of light-emitting diodes. However， there are a large number of defects on the surface of perovskite and at the interface between the perovskite layer and the transport layer， which seriously affects the performance and stability of the device， and the surface/interface treatment has been proven to be an effective way to reduce the interface defects and improve the performance of the device. Therefore， a surface treatment strategy of adding guanidine acetate to the extractant was reported， which could effectively reduce the surface defects and improve the morphology of the perovskite film， thereby increasing the photoluminescence quantum yields of perovskite film from 64% to 79%. The maximum efficiency of the devices prepared based on the surface treatment of perovskite films can reach 11.66% and the maximum brightness exceeds 1 285 cd·m-2， which is significantly better than that of the control devices（6.69%， 689 cd·m-2）， and also shows better stability. This study provides an effective perovskite surface treatment strategy to improve the performance and stability of perovskite light-emitting diodes.关键词：perovskite;lighting-emitter diode;surface treatment;quasi-2D;Defect passivation
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发布时间：2024-04-26 - “最新研究突破：采用InP/InGaAsP增益材料的超辐射发光二极管，通过优化外延结构，显著提升了光纤陀螺核心元件的性能和可靠性。”摘要：As the core component of fiber optic gyroscopes （FOG）， the performance of the superluminescent diodes directly affects the accuracy of the FOG. The higher the output power of the superluminescent diodes， the better the signal-to-noise ratio received by the gyroscope. InP/AlGaInAs have the advantage of high electron confinement efficiency. However， due to the problem of Al oxidation， they pose certain risks in terms of application reliability. In this paper， the InP/InGaAsP are used as gain materials， and the electron confinement efficiency of the quantum wells is improved by adopting the broad bandgap InGaAsP electron blocking layer in the epi-structure. Experimental results show that the electron blocking layer increases the maximum output power of the laser diode from 69 mW to 92 mW. Furthermore， by optimizing the material growth rate to improve the quality of both the active region and the strained electron blocking layer， it is observed that the reliability of the laser diode is significantly improved after aging for 1 000 h， with threshold and power variation falling within acceptable ranges. Finally， superluminescent diode （SLD） chips were fabricated， and the tested results showed that the electron blocking layer increased the saturated output power of SLD chips from 19 mW to 24 mW at room temperature. The saturated operating current of SLD also increased， with a spectral width of 80 nm and a center wavelength of 1 500 nm. Furthermore， after aging for 1 000 h， the threshold and power of SLD remained stable without performance degradation.关键词：superluminescent diodes;InP/InGaAsP;electron blocking layer;growth rate of InP materials
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发布时间：2024-04-26 - 摘要：Thermally activated delayed fluorescence （TADF）-type light-emitting electrochemical cells （TADF-LECs） have attracted much attention owing to their peculiar all-exciton-harvesting merits from purely organic materials. However， restricted by the property of charge-transfer excited state， almost all TADF-LECs displayed very broad electroluminescent spectra， e.g. a full width at half maximum （FWHM） as wide as 100 nm or more， which are difficult to meet the demands of high color purity. In view of this， this work attempts for the first time to construct LECs via TADF-sensitized fluorescence （TSF） strategy， i.e. TSF-LECs. The efficient TSF-LECs were successfully fabricated by selecting a suitable p-/n-doped host matrix， a nonionic TADF sensitizer， a fluorescent dye with high absorption coefficient and an ionic liquid solid-state electrolyte as the emissive layer of TSF-LEC. The energy transfer and exciton loss pathways in those TSF-LECs devices were further discussed in details. The as-fabricated TSF-LECs achieved high overall performance， that is reaching a peak external quantum efficiency （EQEmax） of 3.7% and a bright peak luminance （Lmax） of 2 285 cd·m-2. Importantly， compared with the TADF-LEC reference device， the FWHM of TSF-LEC is reduced from 106 nm to 38 nm. This work will pave the road for further designing and constructing TSF-LECs both from material and device points of view.关键词：light-emitting electrochemical cells;TADF-sensitized fluorescence;BODIPY;thermally activated delayed fluorescence
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发布时间：2024-04-26 - 摘要：Cu+ doped Cs2AgBiBr6 double perovskite was synthesized by hydrothermal method and solar cells were fabricated based on this material. Optoelectronic properties were explored by ultraviolet-visible spectroscopy， fluorescence emission spectroscopy， X-ray photoelectron spectroscopy， incident photon-to-electron efficiency， photocurrent-voltage curves. We found that Cu+ doping can significantly enhance the optical absorption of Cs2AgBiBr6 powder samples， but has almost no effect on Cs2AgBiBr6 films， which can be attributed to the decomposition of Cu phase perovskite during the process of dissolving in dimethyl sulfoxide. The experimental results show that when the Cu+ doping amount is low， the photoelectric conversion efficiency of solar cells is significantly improved. This is due to the regulatory effect of Cu+ doping on the crystallization process of Cs2AgBiBr6 thin films， and the defect density of perovskite thin films can be efficiently reduced by Cu+ doping. In the end， solar cells based on Cu+ doping achieved a maximum power conversion efficiency of 1.93%.关键词：Cs2AgBiBr6;Cu+ doped;solar cell;perovskite
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发布时间：2024-04-26
Device Fabrication and Physics
- 摘要：Suppressing the formation of twisted intramolecular charge transfer （TICT） can markedly improve the fluorescence intensity and photostability of luminescent materials. However， accurate methods for predicting the presence of TICT are currently lacking. This paper investigated the excited state dynamics of N，N-dimethyl-6-propionyl-2-naphthylamine （PRODAN） across various solvents utilized the Kamlet-Taft theory， coupled with both steady-state and transient absorption spectroscopy， complemented by quantitative calculations. The analysis of steady-state spectra revealed that the primary determinant of the Stokes redshift in the PRODAN complexes is the solvent's polarity and hydrogen-donating capacity. Transient absorption spectra provided insights into fast timescales（τ1 and τ2）， corresponding to the formation of intramolecular charge transfer and TICT processes， while slower timescales （τ3 and τ4） were associated with solvation and fluorescence radiation processes. Furthermore， experimental findings demonstrated that an increase in solvent polarity and hydrogen-donating ability expeditiously influences the dynamics processes within PRODAN hydrogen-bonded complexes. Theoretical computations solidified these observations， confirming the formation of a stable TICT state in highly polar and strongly hydrogen-donating methanol solvent. These insights not only contribute to our understanding of the ultrafast dynamics of PRODAN but also provide valuable guidance for the strategic design of fluorescent probe molecules and thoughtful solvent selection in the field of fluorescence research.关键词：twisted intramolecular charge transfer;excited state dynamics;transient absorption spectroscopy;quantum chemical calculation
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发布时间：2024-04-26
Theoretical Calculation and Spectral Analysis
- 摘要：The poor substrate conductivity and thermal properties have been a big challenge for GaN-based LEDs grown on sapphire substrates. Utilizing laser lift-off technology to transfer GaN-based LEDs from sapphire substrates to alternative substrates has emerged as an effective solution. This paper employed ultrafast picosecond laser to detach semi-polar GaN-based LEDs overgrown on patterned sapphire substrates and successfully transfered them to Si substrates， forming vertical structure LED devices. SEM measurements revealed that at a laser energy density of 1.3 J/cm²， efficient decomposition of the sapphire and GaN interface occurred， minimizing adverse effects on the devices. Raman spectroscopy results demonstrated effective stress release in the GaN layer， in which the residual stress decreases from 1.42 GPa to 0.29 GPa. I⁃V measurements of the fabricated vertical structure LEDs showed an increase in forward current from 0.164 mA to 0.759 mA at 5 V voltage， along with an enhancement in photoluminescence and electroluminescence performances. This study presents experimental research on ultrafast laser lift-off of semi-polar GaN-based LEDs on sapphire substrates， providing support for the development of low-damage， high-efficiency transfer technologies. It holds promise in accelerating the advancement and application of semi-polar GaN-based LEDs.关键词：LEDs;ultrafast lasers;patterned sapphire;semipolar plane;GaN
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发布时间：2024-04-26
Luminescence Industry and Technology Frontier
- 摘要：A new method for the rapid detection of neonicotinoid pesticides based on metal halide perovskite quantum dot fluorescent probes was constructed by taking neonicotinoid pesticides as the target and combining fluorescence sensing strategies. The linear detection range of the method was 0-20 mg/L， the linear correlation coefficient was 0.993 9， the detection limit was 0.17 mg/kg. The recovery rate of clothianidin spiked in banana and radish samples was 79.3%-115.4%， and the relative standard deviation was less than 9.4%. This method has high sensitivity， high selectivity and applicability， and provides an effective detection technology for the risk prevention and control of clothianidin in agricultural products and food. The interaction between clothianidin and perovskite quantum dots was studied. The results showed that the interaction between perovskite quantum dots and clothianidin was a dynamic process， and the fluorescence quenching of clothianidin to perovskite quantum dots was static quenching of new complexes formed by hydrogen bonds or van der Waals forces. Its content can be used as the technical basis of other spectral analysis methods， and its analysis and detection results can provide valuable suggestions for the safety supervision of fruits and vegetables.关键词：metal halide perovskite;quantum dots;rapid detection;neonicotinoid pesticides
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发布时间：2024-04-26
Luminescence Applications and Interdisciplinary Fields
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