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Multipoint Nanolaser Array in an Individual Core-Shell CdS Branched Nanostructure
摘要： Nanoscale laser arrays are attractive for their potential applications in highly integrated nanodevices, which are always obtained by nanowire arrays with complicated fabrication techniques. Here, a quite different nanolaser array is successfully realized based on a highly ordered core–shell CdS branched nanostructure with implanted Sn nanoparticles in junctions that split the individual multichannel nanostructures to various microcavities with effective light confinement and oscillation, thus to achieve a multipoint nanolaser array. Under the excitation of an ultraviolet laser, the strong band-edge emission can be well reflected between Sn nanoparticles at junctions and effectively scattered into branch segments due to Sn nanoparticles existence in junctions, furthermore oscillating in various microcavities along trunks or branches to form multipoint lasing from Fabry-Pérot (F-P) mode with a quality factor up to 990 and the low threshold at around 3.78 MW cm?2. The corresponding fluorescent microscope images further demonstrate the formation of multipoint F-P lasing at various segments. The theoretical simulation indicates that implanted Sn nanoparticles work as hot point to enhance the confinement of light around the Sn centers. The existence of surface plasmon from the Sn metal particles is further confirmed by the polarization dependent photoluminescence measurement. The results provide a new way to realize nanolaser arrays.
关键词： core–shell structures,CdS branched nanostructure,nanolaser arrays,electric field distribution
更新于2025-09-23 15:21:01
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EXPRESS: A Study of the Surface of Fe <sub/>3</sub> O <sub/>4</sub> @SiO <sub/>2</sub> Nanoparticles Functionalized with Different Groups Using a Photoacoustic Infrared Spectroscopic Method
摘要： A permanent development of hybrid materials based on the highly absorptive or opaque materials has prompted a need of analytical tools, which are able to overcome obstacles connected with their physicochemical features. Iron oxide (II, III) (Fe3O4) nanoparticles gained a huge attention as supporters, as they are not only easily accessible using various synthetic approaches, but they also exhibit homogeneity and paramagnetic properties, which make them easily separable materials. Nevertheless, the classic infrared spectroscopic studies might meet several problems with characterization of such systems. Therefore, infrared spectroscopy in photoacoustic mode using Fourier transform infrared–photoacoustic infrared spectroscopy (FT-IR PAS) can be an extremely sensitive and exact analytical tool for investigation of the magnetite-based hybrid materials surface. Herein, we present a synthesis of Fe3O4 nanoparticles using co-precipitation method with their subsequent encapsulation within silica matrix decorated with different silanes containing various terminal functional groups. The proper syntheses of core/shell structures were confirmed using the FT-IR PAS method. Each spectrum exhibited specific bands corresponding to vibrations of magnetite particles, silica lattice and particular surface functional groups, which strictly indicated successful grafting of silanes onto Fe3O4 surface.
关键词： PAS,Magnetite nanoparticles,Fourier transform infrared,core/shell structures,surface analysis,photoacoustic infrared spectroscopy,FT-IR PAS,FT-IR
更新于2025-09-19 17:13:59
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Development of InP Quantum Dot-based Light Emitting Diodes
摘要： High performance quantum dot light emitting diode (QLED) is being considered as the next generation technology for energy efficient solid-state lighting and displays. InP QLED is the most promising alternative of the toxic CdSe QLED. Unlike the problems of poor hole injection in CdSe-based QLED, highly delocalized electrons and parasitic emissions are serious problems in green-emitting InP QLED. The loss mechanism and device physics in InP QLED have not been sufficiently studied since the first report of InP QLED in 2011. This review summarized the recent efforts on improving the performance of InP QLED, from the perspectives of core/shell structures to optimization of carrier transport layers. It is our intention to conduct a review as well as clarify some previous misunderstandings on the device physics in InP QLED, and provide some insights for the possible solutions of the challenging problems in InP QLED.
关键词： InP quantum dots,carrier transport layers,parasitic emissions,core/shell structures,QLED
更新于2025-09-16 10:30:52
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Nanoparticle-Mediated Cavitation via CO2 Laser Impacting on Water: Concentration Effect, Temperature Visualization, and Core-Shell Structures
摘要： By taking advantage of seeded polymer nanoparticles and strong photo energy absorption, we report co2 laser impacting on water to produce cavitation at the air/water interface. Using a high-speed camera, three regimes (no cavitation, cavitation, and pseudo-cavitation) are identified within a broad range of nanoparticles concentration and size. The underlying correlation among cavitation, nanoparticles and temperature is revealed by the direct observation of spatiotemporal evolution of temperature using a thermal cameral. These findings indicate that nanoparticles not only act as preexisted nuclei to promote nucleation for cavitation, but also likely affect temperature to change the nucleation rate as well. Moreover, by exploiting a compound hexane/water interface, a novel core-shell cavitation is demonstrated. This approach might be utilized to attain and control cavitations by choosing nanoparticles and designing interfaces while operating at a lower laser intensity, for versatile technological applications in material science and medical surgery.
关键词： temperature visualization,nanoparticle,CO2 laser,cavitation,core-shell structures
更新于2025-09-12 10:27:22
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Wet non-thermal integration of nano binary silicon-gold system with strong plasmonic and luminescent characteristics
摘要： We report on a wet none thermal integration of the binary silicon-gold nano system. Instead of thermally based gas-solid procedures, we use charge exchange/injection-based procedures in a chemical wet environment. SEM and TEM imaging and EDX show 0-D gold-silicon core-shell structures with diameters ranging from 6 to 500 nm in addition to a variety of silicon and gold nano structures. Optical and florescence spectroscopy show that colloids exhibit strong red luminescence and plasmonic resonance in the visible. Mie theory analysis of light scattering is in agreement with the optical observation. The results and procedures are discussed in terms of the relative electron/hole affinity, Schottky potential barrier, strength of the metal-silicon bond, as well as the surface diffusion of metal atoms or clusters on the interface of the constituent materials. Integration of gold and silicon, at the nanoscale in the form core-shell architecture affords the functionalities and attributes of plasmonic light scattering imaging and fluorescence imaging that would be useful for a wide variety of applications, including optical filters, sensing, therapeutics and tracking, and cancer therapy.
关键词： plasmonic,silicon-gold nano system,luminescent,Mie theory,core-shell structures
更新于2025-09-12 10:27:22
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Record High External Quantum Efficiency of 19.2% Achieved in Light‐Emitting Diodes of Colloidal Quantum Wells Enabled by Hot‐Injection Shell Growth
摘要： Colloidal quantum wells (CQWs) are regarded as a highly promising class of optoelectronic materials, thanks to their unique excitonic characteristics of high extinction coefficients and ultranarrow emission bandwidths. Although the exploration of CQWs in light-emitting diodes (LEDs) is impressive, the performance of CQW-LEDs lags far behind other types of soft-material LEDs (e.g., organic LEDs, colloidal-quantum-dot LEDs, and perovskite LEDs). Herein, high-efficiency CQW-LEDs reaching close to the theoretical limit are reported. A key factor for this high performance is the exploitation of hot-injection shell (HIS) growth of CQWs, which enables a near-unity photoluminescence quantum yield (PLQY), reduces nonradiative channels, ensures smooth films, and enhances the stability. Remarkably, the PLQY remains 95% in solution and 87% in film despite rigorous cleaning. Through systematically understanding their shape-, composition-, and device-engineering, the CQW-LEDs using CdSe/Cd0.25Zn0.75S core/HIS CQWs exhibit a maximum external quantum efficiency of 19.2%. Additionally, a high luminance of 23 490 cd m?2, extremely saturated red color with the Commission Internationale de L’Eclairage (CIE) coordinates of (0.715, 0.283), and stable emission are obtained. The findings indicate that HIS-grown CQWs enable high-performance solution-processed LEDs, which may pave the path for future CQW-based display and lighting technologies.
关键词： core/shell structures,colloidal quantum wells,nanoplatelets,hot injection,light-emitting diodes
更新于2025-09-12 10:27:22
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Lattice Strain Formation through Spin‐Coupled Shells of MoS <sub/>2</sub> on Mo <sub/>2</sub> C for Bifunctional Oxygen Reduction and Oxygen Evolution Reaction Electrocatalysts
摘要： Identifying effective means to improve the electrocatalytic performance of transition metal dichalcogenides in alkaline electrolytes is a significant challenge. Herein, an advanced electrocatalyst possessing shells of molybdenum disulfide (MoS2) on molybdenum carbide (Mo2C) for efficient electrocatalytic activity in alkaline electrolytes is reported. The strained sheets of curved MoS2 surround the surface of Mo2C, turning the inactive basal planes of MoS2 into highly active electrocatalytic sites in the alkaline electrolyte. The van der Waals layers, which even possess van der Waals epitaxy along (100) facets of MoS2 and Mo2C, enhance the spin coupling between MoS2 and Mo2C, providing an easy electron transfer path for excellent electrocatalytic activity in alkaline electrolytes and solving the stability issue. In addition, it is found that curved MoS2 sheets on Mo2C show 3.45% tensile strain in the lattice, producing excellent catalytic activity for both oxygen reduction reaction (ORR) (with E1/2 = 0.60 V vs RHE) and oxygen evolution reaction (OER) (overpotential = 1.51 V vs RHE at 10 mA cm?2) with 60 times higher electrochemical active area than pristine MoS2. The unique structure and synthesis route outlined here provide a novel and efficient approach toward designing highly active, durable, and cost-effective ORR and OER electrocatalysts.
关键词： bifunctional,spin coupled,core–shell structures,oxygen electrocatalysis,lattice strain
更新于2025-09-11 14:15:04