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Grain Boundary and Interface Passivation with Corea??Shell Au@CdS Nanospheres for Higha??Efficiency Perovskite Solar Cells
摘要： The plasmonic characteristic of core–shell nanomaterials can effectively improve exciton-generation/dissociation and carrier-transfer/collection. In this work, a new strategy based on core–shell Au@CdS nanospheres is introduced to passivate perovskite grain boundaries (GBs) and the perovskite/hole transport layer interface via an antisolvent process. These core–shell Au@CdS nanoparticles can trigger heterogeneous nucleation of the perovskite precursor for high-quality perovskite films through the formation of the intermediate Au@CdS–PbI2 adduct, which can lower the valence band maximum of the 2,2,7,7-tetrakis(N,N-di-p-methoxyphenyl-amine)9,9-spirobifluorene (Spiro-OMeTAD) for a more favorable energy alignment with the perovskite material. With the help of the localized surface plasmon resonance effect of Au@CdS, holes can easily overcome the barrier at the perovskite/Spiro-OMeTAD interface (or GBs) through the bridge of the intermediate Au@CdS–PbI2, avoiding the carrier accumulation, and suppress the carrier trap recombination at the Spiro-OMeTAD/perovskite interface. Consequently, the Au@CdS-based perovskite solar cell device achieves a high efficiency of over 21%, with excellent stability of ≈90% retention of initial power conversion efficiencies after 45 days storage in dry air.
关键词： perovskite photovoltaic devices,interface passivation,Au@CdS,core–shell nanoparticles
更新于2025-09-19 17:13:59
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Tunable emission of cadmium-free transition metal (Cu, Mn, Ag) co-doped ZnInS/ZnS core-shell quantum dots
摘要： Color tunable quantum dots (QDs) based on the Cu, Mn, Ag co-doped ZnInS core and ZnS outer-shell were synthesized by using an eco-friendly method. Core-shell doped QDs with the average size of 3.85 nm were obtained by using a one-pot synthesis followed by a hot injection with n-dodecanethiol (DDT) and oleylamine (OLA) as stabilizers in oil phase. Cu, Mn and Ag ions were introduced as single-dopant or co-dopants during the synthesis, providing an effective means to control the emission color of the QDs. The as-synthesized QDs showed photoluminescence emission ranging from green (530 nm) to near-red (613 nm), adjusted by doping components, dopant concentration, and Zn/In ratio. Importantly, quasi-white emission has been achieved by controlling the concentration of co-doped metal ions (Mn, Cu and Ag). The primary results demonstrated the promising potential of co-doped QDs as alternative materials for future high quality white LED applications.
关键词： doping,tunable emission,white light,core-shell,zinc group quantum dots
更新于2025-09-19 17:13:59
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Au@Ag Corea??Shell Nanorods Support Plasmonic Fano Resonances
摘要： In this work, we investigated experimentally and theoretically the plasmonic Fano resonances (FRs) exhibited by core–shell nanorods composed of a gold core and a silver shell (Au@Ag NRs). The colloidal synthesis of these Au@Ag NRs produces nanostructures with rich plasmonic features, of which two different FRs are particularly interesting. The FR with spectral location at higher energies (3.7 eV) originates from the interaction between a plasmonic mode of the nanoparticle and the interband transitions of Au. In contrast, the tunable FR at lower energies (2.92–2.75 eV) is ascribed to the interaction between the dominant transversal LSPR mode of the Ag shell and the transversal plasmon mode of the Au@Ag nanostructure. The unique symmetrical morphology and FRs of these Au@Ag NRs make them promising candidates for plasmonic sensors and metamaterials components.
关键词： Au@Ag NRs,metamaterials,core–shell nanorods,plasmonic Fano resonances,plasmonic sensors
更新于2025-09-19 17:13:59
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Synthesis, characterization and the photoinduced electron-transfer energetics of CdTe/CdSe type-II core/shell quantum dots
摘要： The CdTe/CdSe type-II core/shell quantum dots (QDs) were chemically synthesized in a noncoordinating solvent. The optical properties and structures of the synthesized QDs were characterized by absorption spectroscopy (Abs), photoluminescence (PL) spectroscopy, PL-decay lifetime, X-ray diffraction (XRD), transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDX). The PL peak of the CdTe/CdSe core/shell QDs could be tuned from 698 nm (1.77 eV) to 780 nm (1.59 eV) by changing the thickness of CdSe shell and fixing the size of CdTe core. The PL quantum yields (QYs) of these QDs were from 14.1% to 31.7% and their full width at half maximum (FWHM) of PL peaks was kept below 0.12 eV during the growth process of CdSe shell on CdTe core. Compared to CdTe cores, the CdTe/CdSe type-II core/shell QDs have much longer PL decay times, up to ~100 ns. Based on Marcus theory, the charge transfer (CT) of CdTe/CdSe 1-5 monolayers (MLs) type-II core/shell QDs has been studied and the effects of quantum confinement on the structure parameters have been revealed. The reorganization energies (RE) of the CdTe/CdSe (1-5 ML) type-II core/shell QDs for the electron transfer (ET) were in the range from 60 meV to 106 meV and was found that ET takes place in the Marcus inverted region (-?G0 ET > λCT) which is typical for these QDs.
关键词： core/shell,reorganization energy,type-II quantum dots,spatial separations,CdTe/CdSe
更新于2025-09-19 17:13:59
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Nonlinear optical properties of lens-shaped core/shell quantum dots coupled with a wetting layer: effects of transverse electric field, pressure, and temperature
摘要： In this study, we numerically determined the intra-band transition lifetime of carriers as well as, the linear, nonlinear, and total absorption coefficients fro lens-shaped core/shell quantum dot structures. Our computations considered the combined effects of the wetting layer, pressure, applied transverse electric field, temperature, and core/shell sizes. By using suitable choices for these parameters, we found that a red or blue shift in the energy of the absorption spectrum could be achieved. In addition, the largest absorption coefficient was obtained when an intense transverse electric field was applied along the diagonal of the cross section of the structure considered. Hence, the magnitude of the absorption coefficient increased by 50%. Moreover, our results showed that the transition lifetime of the carriers decreasedas the temperatureincreased, whereas it increased as the pressure increased. Comparative analysis of a semi-spherical core/shell quantum dot system showed that the transition lifetime was shorter than that of the lens-shaped core/shell quantum dot structure, which was 255 ns.
关键词： Nonlinear optical properties,Electric field,Pressure,Temperature,Lens-shaped core/shell quantum dot
更新于2025-09-19 17:13:59
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Transition Metal Carbide Core/Shell Nanoparticles by Ultra-Short Laser Ablation in Liquid
摘要： Transition metal carbide nanoparticles are a class of technological interesting materials with a wide range of applications. Among metal carbides, tantalum carbides have good compatibility with the biological environment while molybdenum carbides are used as catalyst in electrochemical reactions. Laser ablation of bulk transition metal targets in some liquids is here reported and laser ablation in organic solvents is used as simple synthetic strategy for the production of carbide nanostructures. Herein, the nanoparticles produced by ultra-short laser ablation of tantalum and molybdenum in water, acetone, ethanol and toluene have been characterized by TEM, XRD and XPS analysis. The combined effect of metal and solvent chemical and physical properties on the composition of the nanomaterials obtained has been pointed out. In particular, the different reactivity of Ta and Mo with respect to oxidizing species determines the composition of particles obtained in water, on the other hand the organic solvents decomposition allows to obtain transition metal carbide (TMC) nanoparticles. The observed carbonaceous shell formed on TMC allows to protect the particle’s carbidic core and to improve and tailor the applications of these nanomaterials.
关键词： ultrashort laser ablation in liquid,transition metal carbide,core/shell nanostructures,solvent degradation
更新于2025-09-19 17:13:59
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Environmentally friendly Mn-alloyed core/shell quantum dots for high-efficiency photoelectrochemical cells
摘要： Colloidal quantum dots (QDs)-based photoelectrochemical (PEC) cells are cost-effective devices showing remarkable solar-to-fuel conversion efficiency. However, the extensive use of highly toxic elements (e.g. Pb and Cd) in QD’s synthesis and device fabrication is still a major challenge towards their practical development. Herein, we fabricate a solar-driven PEC cell based on environment-friendly Mn-alloyed CuInS2 (MnCIS)/ZnS core/shell QDs, showing more favorable band alignment, efficient charge transfer, reduced charge recombination as well as lower charge transfer resistance with respect to the control device fabricated using unalloyed CuInS2 (CIS)/ZnS core/shell QDs. An unprecedented photocurrent density of ~5.7 mA/cm2 with excellent stability was obtained in as-fabricated MnCIS/ZnS core/shell QDs-based PEC device when operated under standard one solar irradiation (AM 1.5G, 100 mW/cm2). These results indicate that the transition metal-alloyed environment-friendly core/shell QDs are promising for next-generation solar technologies.
关键词： Colloidal quantum dots,Photoelectrochemical cells,Mn-alloyed CuInS2,ZnS core/shell,Solar-to-fuel conversion
更新于2025-09-19 17:13:59
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Synthesis of ZnO and Au@ZnO core/shell nano-catalysts by pulsed laser ablation in different liquid media
摘要： We report the synthesis of colloidal solution of ZnO and Au@ZnO core/shell nanoparticles by one-pot nanosecond laser ablation (1st harmonic of Nd:YAG laser) method in different liquid media (Ultrapure water and Chloroauric acid). The structural, morphological and optical properties had been studied. X-ray diffraction analysis showed their hexagonal wurtzite structure while UV–vis analysis investigated the quantum confinement and surface plasmon resonance of the prepared nanostructured particles with significant changes in color behavior. Transmission electron microscopic analysis revealed the homogeneous spherical shape with an average particle size about 39 nm and 50 nm for Au@ZnO core/shell and ZnO, respectively. Also, it is confirmed that the produced nanostructured material in the case of chloroauric acid is core/shell structure where Au is the core while ZnO is the shell. In contrast to ZnO, Au@ZnO displayed more significant Chemical-catalytic degradation activity toward the degradation of 4-nitrophenol to 4-aminophenol in only 4 min rather than ZnO that required 12 min for the same degree of conversion.
关键词： ZnO,Laser ablation,Nanoparticles,4-nitrophenol,Core/shell
更新于2025-09-19 17:13:59
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Light-induced Polymer Response Through Thermoplasmonics Transduction in Highly Monodisperse Core-Shell-Brush Nanosystems
摘要： Smart nanosystems that transduce external stimuli to physical changes are an inspiring challenge in current materials chemistry. Hybrid organic-inorganic materials attract great attention due to the combination of building blocks responsive to specific external solicitations. In this work, we present a sequential method for obtaining an integrated core-shell-brush nanosystem that transduces light irradiation into a particle size change through a thermoplasmonic effect. We first synthetize hybrid monodisperse systems made up of functionalized silica colloids covered with controllable thermo-responsive Poly(N-isopropylacrylamide), PNIPAm, brushes, produced through radical photopolymerization. This methodology was successfully transferred to Au@SiO2 nanoparticles, leading to a core-shell-brush architecture, in which the Au core acts as a nano-source of heat; the silica layer, in turn, adapts the metal and polymer interfacial chemistries and can also host a fluorescent dye for bioimaging. Upon green LED irradiation, a light-to-heat conversion process leads to the shrinkage of the external polymer layer, as proven by in situ DLS. Our results demonstrate that modular hybrid nanosystems can be designed and produced with photo-thermo-physical transduction. These remote-controlled nanosystems present prospective applications in smart carriers, responsive bioscaffolds or soft robotics.
关键词： photothermal effect,hybrid materials,in-situ DLS,UV-photo induced polymerization,core-shell-brush colloids,Smart nanosystems
更新于2025-09-19 17:13:59
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Plasmonic Ag@TiO <sub/>2</sub> Core-Shell Nanoparticles for Enhanced CO <sub/>2</sub> Photoconversion to CH <sub/>4</sub>
摘要： Ag@TiO2 nanoparticles (NPs) with Ag metal cores and TiO2 semiconductor shells were prepared with a hydrothermal method and their structure was characterized by scanning electron microscopy, transmission electron microscopy and X-ray diffraction. The core-shell Ag-TiO2 NPs were deposited on a glass plate and employed as photocatalysts for CO2 conversion by irradiation of solar simulator (AM1.5) under CO2 atmosphere. Selective CH4 evolution by CO2 photoconversion was attained with the core-shell Ag@TiO2 NP photocatalyst. The CH4 evolution rate normalized by specific surface areas was ten times higher than those of reference TiO2 NPs and conventional TiO2 NPs with accompanying Ag deposits. The role of the Ag core was also demonstrated in photodecomposition of a dye by the core-shell Ag@TiO2 NPs. These results suggested the high photocatalytic activity of the core-shell Ag@TiO2 NPs was archived due to bandgap improvement of the TiO2 shell and increase of photon flux to the TiO2 shell by the plasmonic Ag core.
关键词： Photocatalytic CO2 Reduction,Surface Plasmonic Resonance,Ag@TiO2,Core-shell Structure,Light Scattering Effect
更新于2025-09-19 17:13:59