最新刊期
卷 45 ， 期 2 ， 2024
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Controlled Doping of Mn（Ⅱ） Ions in CsPb
X 3 Perovskite Nanocrystals and Luminescence Properties 增强出版 AI导读
摘要：Mn ion doping strategy emerged as a widely employed strategy for enhancing the stability of CsPbX3 perovskite nanocrystals （NCs） and regulating Pb content. Nevertheless， the rapid reaction rate associated with ion doping poses significant challenges for controllable synthesis. Herein， we have employed both the one-step and two-step hot injection methods to synthesize CsPbCl3∶Mn2+ NCs with varying levels of Mn2+ doping， allowing for approximate and precise control of Mn2+ incorporation. Through an investigation of their structural and luminescent properties， these NCs are divided into alloy structure and doping structure， elucidating distinct mechanisms involved in one-step and two-step Mn2+ regulation. The alloy structure nanocrystals synthesized by one-step method have higher Mn2+ doping amount than that by two-step method under the same Pb∶Mn feeding ratio. Consequently， the Mn-related emission peak of nanocrystals at about 610 nm is more intense with maximum photoluminescence quantum yield （PLQY） of 77%， and the PLQY of the doped nanocrystals synthesized by the two-step method is also higher in the case of less Mn2+. At the same time， the controlled doping of Mn2+ improves the stability of perovskite nanocrystals， and the original morphology and luminescence properties remained stable after four weeks. Notably， alloy structure is more favorable for improving the luminescence stability of intrinsic excitons compared with doping structure. In addition， CsPb（ClxBr3-x）∶Mn2+ perovskite nanocrystals with excellent luminescent properties have been synthesized. The fluorescence spectrum can be regulated between 404-640 nm， but when the Br- content is high， the emission peak associated with Mn disappears. This is due to the mismatch between the energy band of CsPbBr3 and the 4T1-6A1 energy level of Mn2+. This paper emphasizes the significance of precise Mn2+ doping control in the preparation of CsPbCl3∶Mn2+ perovskite NCs， which is of great significance for the controlled synthesis of nanocrystals.关键词：all-inorganic perovskites;CsPbCl3∶Mn2+;tunable component- 1357
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发布时间：2024-03-04
Cover Story
- 摘要：Hybrid perovskite semiconductors have attracted enormous interest in the field of optoelectronic devices for creating high-performance solar cells， light-emitting diodes， and photodetectors owing to their tunable narrow band gap， high optical absorption， high charge-carrier mobility， and low cost， etc. Among them， perovskite single-crystalline thin-films show greater promise as an ideal matrix for optoelectronic applications because of their absence of grain boundaries， lower impurity， and lower defect densities. The space-confined method was usually used for the growth of perovskite single-crystalline thin-films， where a polymer hole-transport layer was employed to accelerate the ion diffusion. However， this solution-processed method will inevitably bring in the interfacial defects and induce poor charge-carrier injection between the perovskite single-crystalline thin-film and hole-transport layer. Herein， we introduced the template stripping method to solve this problem that enables direct thermal-deposition onto two sides of the perovskite single-crystalline thin-film. A novel perovskite single-crystalline thin-film photodetector can be constructed by a device structure of Cu/BCP/C60/MAPbBr3/MoO3/Ag. Then， an ultrasensitive and fast perovskite single-crystalline thin-film photodetector can be realized with an on-off ratio of 3.1 × 103， a responsivity up to 7.15 A/W， a detectivity of 5.39 × 1012 Jones， and an external quantum efficiency of 1794%， due to the optimal device structure and improved charge-carrier transport. These results indicate that the template stripping method provides a feasible approach to further improve the performance of perovskite single-crystal photodetectors.关键词：Hybrid perovskite semiconductors;Perovskite single-crystalline thin-films;Template stripping method;photodetectors
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发布时间：2024-03-04 -
MOCVD Epitaxial Growth and Characterization of Polar, Semipolar and Nonpolar InN Thin Films 增强出版 AI导读
摘要：In this paper， polar （0002）， semipolar （11-22） and nonpolar （11-20） planes of InN thin films were grown on different planes of sapphire （Al2O3） substrates by using metal-organic chemical vapor deposition （MOCVD） technology， and the structural and optical properties of these InN thin films were intensively investigated by various characterization means. The X-ray diffraction （XRD） curves show the stronger diffraction peaks of the （0002）， （11-22） and （11-20） planes of InN， indicating the relatively high crystalline quality of the InN films. The scanning electron microscopy （SEM） surface images reveale that the surface morphology of polar （0002）-plane InN was smoother， while incompletely merged holes were presented on both semipolar and nonpolar InN surfaces. Photoluminescence （PL） spectra demonstrate that the peak energies of different planes of InN were around 0.63 eV and gradually red-shifted from polar， semipolar to nonpolar. In addition， the transmission spectra measured with a visible-infrared spectrophotometer show that the absorption edge of polar （0002）-plane InN is around 0.85 eV， while the absorption edge of semipolar （11-22） and nonpolar （11-20）-planes InN is around 0.78 eV， suggesting a larger Stokes’ shift for polar InN.关键词：semipolar;nonpolar;InN film;epitaxial growth- 290
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发布时间：2024-03-04
Research Letter
- 摘要：From the proposing of doublet electroluminescence of free radicals to the successfully achieving of high luminescence efficiency in these materials， and further to developing luminescent diradicals with controllable spin states， this series of innovations have revitalized the field of free radicals that existed a century ago. Here we trace the history of stable organic radicals and provide a detailed account of our research efforts in these unique materials.关键词：organic radicals;stable radicals;doublet emission;OLED;luminescent diradicals
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发布时间：2024-03-04
Expert Perspectives
- 摘要：Organic nonfullerene acceptors， also called fused-ring electron acceptors， are the present one of the mostly attractive organic optoelectronic materials due to their prominent photoelectric conversion property. Based on these materials for the development of organic bulk heterojunction solar cells， their power conversion efficiencies have approached 20% already. Fabrications of highly efficient and stable organic photovoltaic devices are inseparable with continuous explorations on material properties and photovoltaic processes. Among many research systems， the growth of the nonfullerene photovoltaic spin dynamics remains in its infant stage， and its underlying physical mechanism is not yet clear. The photoexcited magneto-photocurrent technique can rationally monitor the polaron pair dissociation at charge transfer states， for a device at working conditions， the technique acts as a powerful tool for in-situ characterizations of photovoltaic spin dynamics. This article contains a joint of experimental and theoretical studies， to scientifically elucidate the present mainstream theories and functional models. These include the hyperfine interaction and the spin-orbit coupling effect at low magnetic fields， and the Δg mechanism at high magnetic fields. The paper explores signal differences in different organic heterojunctions under various characterization conditions， such as bias， temperature and light intensity. Finally， we discuss the applications of the ultrafast spectroscopic technique in the organic bulk heterojunction systems.关键词：non-fullerene acceptors;organic bulk heterojunction solar cells;charge transfer states;magneto-photocurrent;polaron pairs
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发布时间：2024-03-04 -
Current Status and Challenges in Indium Phosphide Quantum Dots and Their Electroluminescence 增强出版 AI导读
摘要：Quantum dots （QDs）， as an ideal light-emitting material， have been attracting a lot of attention from scientists and industry， advancing the development of bio-imaging， lighting， display and other fields.With the gradual increase in awareness of ecological and environmental protection， indium phosphide quantum dots （InP QDs） have received widespread attention as one of the best alternatives to cadmium-based quantum dots. On the one hand， InP QDs have luminescence and photovoltaic properties comparable to those of cadmium-based quantum dots. On the other hand， their luminescence spectral range can cover the entire visible region， and their synthesis process is common to that of cadmium-based quantum dots. However， as InP QDs are special in terms of elemental valence， core-shell lattice matching and reaction kinetics compared to traditional cadmium-based QDs， the development of their synthetic chemistry is still immature， which limits the research process of their photovoltaic applications. Here， we review the indium phosphide QDs system on its development and future needs for displays， by analyzing the current status， problems， challenges， and making an outlook on it. We expect to provide some insights and help for further exploratory research on QDs and their electroluminescent devices （QLEDs）， and to promote the development of cadmium-free， low-toxicity， high-colour purity QDs system.关键词：quantum dots;indium phosphide;QLEDs;high-colour purity;displays- 584
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发布时间：2024-03-04 - 摘要：Persistent luminescent materials are photoluminescent materials that can store external light emission energy and continue to emit luminescence after the cessation of excitation. Due to long afterglow lifetime， no need for in⁃situ excitation， no interference from tissue background signals， and high signal-to-noise ratio， persistent luminescent nanoparticles （PLNPs） are widely used in biomedical detection， biological imaging， and tumor therapy. This article reviews the application progress of the PLNPs in biomedical detection， biological imaging and tumor therapy （chemotherapy， photothermal therapy， photodynamic therapy， and immunotherapy） in recent years， and further explores the challenges in biomedical applications and prospects the future development trends.关键词：persistent luminescent nanoparticles;afterglow;biomedical detection;biological imaging
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发布时间：2024-03-04
Invited Review
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Synthesis and Electroluminescence Properties of Deep Blue Materials Based on Anthracene Core 增强出版 AI导读
摘要：Using anthracene as the basic unit of triplet-triplet annihilation （TTA） blue light materials， two donor-acceptor deep blue TTA materials 4-（10-（dibenzo［b，d］thiophen-4-yl）anthracen-9-yl）benzonitrile（2） and 4-（10-（dibenzo［b，d］thiophen-2-yl）anthracen-9-yl）benzoni-trile（3） were designed and synthesized by introducing dibenzothiophene， a weak electron-donating group， and benzonitrile， a weak electron-withdrawing group into the 9th and 10th positions of anthracene， respectively. Their thermal stability， electrochemical properties， photophysical properties and electroluminescent properties were systematically characterized. The photoluminescence peaks of the two compounds are located at 445 nm and 451 nm， and the photoluminescence quantum yields are 40.2% and 57.9%， respectively. The electroluminescent peaks of the undoped devices based on compounds 2 and 3 are located at 448 nm and 458 nm， respectively， realizing deep blue light emission. The two devices have good luminous efficiency， and their maximum current efficiency is 4.2 cd·A-1and 6.9 cd·A-1， respectively. The maximum power efficiency is 2.3 lm·W-1 and 3.6 lm·W-1， and the maximum external quantum efficiency is 3.8% and 5.6%， respectively. Even at the brightness of 1 000 cd·m-2， the external quantum efficiency of the two devices remains at 3.7% and 5.4%， showing a very low efficiency roll-off.关键词：anthracene;dibenzothiophene;benzonitrile;deep blue TTA material- 268
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发布时间：2024-03-04 -
Crosslinking Agents Enhancing Fluorescence Performance of Carboxylate Graphene Quantum Dots 增强出版 AI导读
摘要：1-（3-dimethylaminopropyl）-3-ethyl carbodiimide hydrochloride （EDC） as a water-soluble carbodiimide crosslinking agent， it is widely used in nanomaterial research. The utilization of EDC is as a key component in the design and functionalization of nanomaterials for diverse applications. This study focused on carboxyl-functionalized graphene quantum dots （C-GQDs） and investigated the impact of EDC on its optical properties which has received limited attention previously. This method can effectively enhance the fluorescence intensity of C-GQDs. In experiments， C-GQDs and EDC were reacted to form C-GQDs/EDC complexes via a one-step aqueous method. Experimental results demonstrate that after reaction with EDC， the fluorescence of C-GQDs/EDC is significant enhanced by approximately 23 times. Additionally， the impact of factors such as solution concentration， light irradiation， and reaction time on fluorescence were also validated. Fluorescence spectroscopy analysis indicates that the luminescence of C-GQDs is the result of a multi-process interplay involving intrinsic， surface， and defect-state energy level transitions. Abundance of defect energy levels in original C-GQDs contributed to the weakened luminescent performance. The mechanistic analysis suggests that the activation reaction occurring between EDC and carboxyl groups plays a role in surface defect passivation， thereby improving the surface-state exciton recombination efficiency of C-GQDs. This effectively addresses the low luminescence issue of C-GQDs. This work extends the potential applications of GQDs and provides a reference for the modulation of the optical properties of GQDs.关键词：graphene quantum dots;fluorescence;crosslinking agent;surface states- 183
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发布时间：2024-03-04 - 摘要：In recent years， near-infrared phosphor-converted light-emitting diode （NIR pc-LED） has attracted widespread attention in the fields of night vision， bioimaging and non-destructive testing. However， obtaining NIR phosphors with both high quantum efficiency and excellent thermal stability remains a great challenge. In this work， we synthesized a novel NIR phosphor BYAGSO∶Cr3+. Under 440 nm excitation， BYAGSO∶Cr3+ shows a broad band emission peaked at 690 nm， which originates from the combination of the spin-forbidden 2E→4A2 transition and spin-allowed 4T2→4A2 transition of Cr3+ in a medium octahedral crystal field environment. Interestingly， this phosphor exhibits excellent thermal stability， and the optimal BYAGSO∶0.06Cr3+ remains at 99% of its initial intensity at 200 ℃. Meanwhile， this phosphor also has considerable quantum efficiency of 30.3%. A NIR pc-LED device was fabricated by combining BYAGSO∶0.06Cr3+ with a 450 nm blue LED chip， which exhibited the output power of 70.83 mW at the driving current of 300 mA， and the photovoltaic conversion efficiency of 11.20% at the driving current of 20 mA. The results indicates that BYAGSO∶0.06Cr3+ is a promising phosphor for NIR pc-LED applications.关键词：near-infrared emission;Cr3+;thermal stability;quantum efficiency;NIR pc-LED
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发布时间：2024-03-04 - 摘要：The poor moisture resistance of Mn4+ doped fluoride red fluorescent powder significantly impacts the photochromic stability of white light-emitting diodes （WLEDs）. This study focuses on the reducibility of green alum solution to reduce Mn4+ on the surface of K2SiF6∶Mn4+ particles， converting it to soluble low-valent Mn2+. This process achieves surface passivation and enhances the humidity resistance of the fluoride particles. After a 360-h immersion in water， the luminescence intensity of the surface-passivated K2SiF6∶Mn4+ particles remained at 95% of the initial intensity， whereas the untreated K2SiF6∶Mn4+ phosphors experienced a rapid decrease to only 46% of their initial value. Additionally， simply soaking the surface-hydrolyzed fluoride fluorescent powder in green alum solution fully restored its original luminescence intensity. Characterization techniques such as Inductively coupled plasma-atomic emission spectroscopy， X-ray photoelectron spectroscopy and elemental spectroscopy confirmed a significant reduction in Mn4+ concentration on the surface of K2SiF6∶Mn4+ particles treated with green alum solution， indicating the formation of an inert shell K2SiF6. This finding elucidates the reason behind the notable improvement in moisture resistance of the fluoride particles. Moreover， even after aging under harsh conditions of high temperature （85 ℃） and high humidity （85%） for 1 000 h， the surface-passivated K2SiF6∶Mn4+ particles in the WLEDs devices still maintained 100% of the red luminescence intensity， which was significantly higher than that of the unpassivated fluoride （59%）， further validating the exceptional environmental stability achieved by the green alum solution-passivated K2SiF6∶Mn4+ red phosphors.关键词：Mn4+ doping;red phosphor;moisture resistance;green alum solution;surface passivation
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发布时间：2024-03-04 - 摘要：Temperature， as a core physical parameter， plays a pivotal role in measurements across various scientific and technological domains. Traditional fluorescence temperature sensors， relying on the energy transfer of the thermo-coupled levels （TCLs） of rare-earth ions， suffer from limited temperature sensitivity and signal discrimination difficulties due to the energy gap constraints between the TCLs. Seeking a superior solution， this study delves into the potential applications of luminescence from oxygen vacancy defects in the field of fluorescence temperature sensors. BaMgSiO4 ceramics were synthesized using a high-temperature solid-phase method. Owing to the minor evaporation of Ba2+ and Mg2+ during the high-temperature sintering process， oxygen vacancies are formed to maintain material electroneutrality. These oxygen vacancy-induced defects， when excited by ultraviolet light at 332 nm， emit light at three distinct wavelengths： 372， 400， 527 nm. These emissions exhibit varying sensitivities to temperature， rendering them suitable for application in fluorescence temperature sensors. Specifically， the absolute temperature sensitivity of a sensor constructed from I372 and I527 was 2.90%·K-1 at 298 K， surpassing the sensitivity of traditional TCLs-based sensors and breaking their sensitivity ceiling. Moreover， the substantial wavelength difference between 372 nm and 527 nm allows the BaMgSiO4 ceramic luminescence to exhibit significant color shifts from room-temperature green emissions to high-temperature blue emissions at 458 K， achieving a visual temperature monitoring effect. Consequently， due to its unique luminescent characteristics stemming from oxygen vacancy defects， BaMgSiO4 ceramics present a novel， high-precision， and visually demonstrative choice for the domain of fluorescence temperature sensors， paving a new research avenue for future temperature measurement technologies.关键词：luminescence from oxygen vacancy defects;fluorescence temperature sensors;energy transfer;visualization
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发布时间：2024-03-04
Synthesis and Properties of Materials
- 摘要：With the rapid development of the information age， higher demands have been placed on the selection of optoelectronic materials and the development of new functionalities in microelectronic devices. Traditional optoelectronic devices mostly rely on the positive photoconductive effect， where the conductivity of semiconductor materials increases under illumination， for functional design. In recent years， another anomalous photoconductive effect called negative photoconductivity（NPC） has been discovered. NPC refers to a decrease in conductivity under light illumination and has attracted attention due to its potential applications in photoelectric detection， logic device， neuromorphic devices， and low-power non-volatile memory. The mechanisms responsible for NPC generally include carrier trapping， adsorption-desorption of surface molecules， surface plasmon polaritons， localized surface plasmon resonances， and photo-radiative heating effects. This article discusses in detail the physical mechanisms of NPC in different optoelectronic devices， analyzes the influence of material selection， device structure design， and band structure variations on NPC effects in different heterojunction devices， and summarizes the practical applications of negative photoconductivity in optoelectronic devices. This provides an important reference for performance optimization of optoelectronic devices and the design of new types of optoelectronic devices， laying a scientific foundation for achieving smaller size， higher optical gain， faster speed， and lower power consumption of future heterojunction optoelectronic information devices.关键词：negative photoconductivity;application;optoelectronic devices
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发布时间：2024-03-04 - 摘要：Based on the energy conversion and energy level system of Er3+ for generating 3 μm mid-infrared laser， rate equations and transmission equations for erbium doped fluoride fiber laser were established. The study systematically investigated the effects of pump structure and fiber length on output power， slope efficiency， as well as the distribution of pump and laser power within the cavity， providing a theoretical foundation for subsequent experiments. The ideal fiber length for the fiber laser with low pump power was determined through simulations， falling in the range of 4-8 m. Ultimately， in the experimental setup， a 4.7 m fiber was chosen for the construction of a continuous-wave mid-infrared erbium-doped fluoride fiber laser. This setup achieved a maximum output power of 1.038 W at a pump power of 5 W and a central wavelength of 2.797 μm， with a slope efficiency of 20.4%.关键词：mid infrared;erbium-doped fluoride fiber laser;rate equation;CW laser
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发布时间：2024-03-04 - 摘要：Due to the excellent optical properties of chalcogenide glasses， they have been extensively investigated in nonlinear optics and other fields， but there is little research based on chalcogenide glass photodetectors. In this paper， we used vacuum co⁃thermal evaporation technology to prepare chalcogenide glass thin films with different silver doped ratios as semiconductor film structure， and designed a self-powered photodetector based on the MIS structure of chalcogenide glass thin films with different silver doped ratios. The response spectrum range of the photodetector was studied， and the results showed that the detector was responsive to light from visible to near infrared regions. The relationship between the response voltage and excitation power was researched for the silver doped chalcogenide glass at 635 nm wavelength laser. For the laser power was less than 10 mW， the response voltage of the photodetector was linearly related to the excitation power. For the laser power was higher than 10 mW， the response voltage of the photodetector appears saturation phenomenon. Moreover， the photodetector exhibits fast light response speed， with rise time and decay time of 3.932 s and 1.522 s， respectively. This study indicates that the chalcogenide glass is a promising method for self-powered photodetectors.关键词：Chalcogenide glass;photodetector;metal-insulator-semiconductor
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发布时间：2024-03-04
Device Fabrication and Physics
- 摘要：A compound of 1，2，3-triazole containing dicarboxylate group was designed and synthesized， and combined with rhodamine B hydrazine to produce an on-off fluorescence probe （L2）. The physicochemical parameters of L2 were characterized by spectroscopy and the computational chemistry methods. The probe L2 showed high selectivity and sensitivity to Hg2+ and ClO- in DMF/Tris-HCl （1∶1， v/v， pH 6.0， 20 μmol/L） and MeOH （20 μmol/L） solutions， respectively. The optical properties of L2 to 19 metal ions and 14 anions were measured by fluorescence and ultraviolet spectra， respectively. The experimental results showed that the presence of Hg2+ and ClO- made L2 have a new emission peak at 585 nm and 576 nm， respectively. Simultaneously， the color change of the solution system can be recognized by the naked eye with the obvious enhancement of fluorescence intensity， indicating that Hg2+ can convert the closed-loop structure of hydrazide rhodamine molecule into an open-loop structure. A new complex is generated in the ratio of 1∶2， which is also confirmed by the results of mass spectrometry， Job's plot， nuclear magnetic titration， and TD-DFT calculation. The detection limits of L2 for Hg2+ and ClO- were 7.45 nmol/L and 0.67 μmol/L， respectively. In addition， bioactivity assays showed that L2 has very low toxicity to HeLa cells and can be used for cell imaging of Hg2+ and ClO- in HeLa cells， suggesting the great potential of L2 for micro-determination of Hg2+ and ClO- in vivo.关键词：1，2，3-triazole;rhodamine B;Hg2+;ClO-;cell imaging
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发布时间：2024-03-04 - 摘要：A platinum（Ⅱ） complex PtppyTPA modified with triphenylamine is synthesized， whose structure and photophysical properties are characterized. The results show that triphenylamine can effectively activate the aggregation-induced emission （AIE） property of PtppyTPA， which can significantly enhance its luminescence in acetonitrile with water content of 50%. The AIE active PtppyTPA is employed as the luminescent probe to realize the luminescence detection of nitroaromatics， including nifedipine （NFD）， 5-chloro-2-nitrotrifluorotoluene （ClNTFT）， 4-bromo-1-fluoro-2-nitrobenzene （BrFNBz）， and 3-nitrotrifluorotoluene （NTFT）. Stern-Volmer equation was utilized to fit the detection data and calculate the detection efficiency with detection limits. The detection efficiency of PtppyTPA for nitroaromatics above is 11.12，0.27，0.25，0.21 L/mmol with the detection limits of 7.1， 291.0， 314.3， 374.2 μmol/L， respectively. PtppyTPA exhibits the highest detection efficiency and the lowest detection limit to NFD. The results show that the detection mechanism of NFD，ClNTFT，BrFNBz and NTFT by PtppyTPA can be attributed to electron transfer.关键词：Platinum（Ⅱ） complex;Aggregation induced luminescence;Nifedipine;Luminescence quenching
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发布时间：2024-03-04
Luminescence Applications and Interdisciplinary Fields
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