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A Facile Film-Nanoctahedron Assembly Route to Plasmonic Metamaterial Absorbers at Visible Frequencies
摘要： Plasmonic metamaterial absorbers (MAs) with broadband and near-perfect absorption properties in the visible region were successfully fabricated via a facile film-colloidal nanoparticle (NP) assembly method. In this approach, colloidal octahedral Au NPs were employed as the surface meta-atoms of MAs, while the nanoscale-thick SiO2 and Al films were used as the dielectric spacer and reflector respectively. It is worth noting that the Au nanoctahedron were randomly assembled onto the Al-SiO2 films, and no effort was made to precisely control their spatial arrangements. The optical characterization showed that the as-prepared MAs exhibited broadband high absorption (average absorptivity above 85%) within the whole visible spectrum for a broad range of incident angles (0°–60°). In particular, two polarization-independent near-perfect absorption peaks (absorptance above 99%) were recorded near 540 nm and 727 nm respectively. Moreover, the absorption properties of the MAs can be effectively controlled and tailored by varying the geometry (the thickness of the dielectric spacer and the surface coverages of the Au nanoctahedron). Electromagnetic simulations further demonstrated that enhanced Mie resonances and strong plasmonic coupling effects were critical for the designed MAs. This work here may provide an efficient and alternative route for the design of scalable visible light absorbers for applications such as solar cells, photothermalvoltaics, and biochemical sensors.
关键词： metamaterial absorbers,broadband and near-perfect absorption,aperiodic nanostructures,optical impedance matching,self-assembly
更新于2025-10-22 19:40:53
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Self-Patterned CsPbBr3 Nanocrystals for High-Performance Optoelectronics
摘要： All-inorganic lead halide perovskites are promising materials for many optoelectronic applications. However, two issues that arise during device fabrication hinder their practical use, namely inadequate continuity of coated inorganic perovskite films across large areas and inability to integrate these films with traditional photolithography due to poor adhesion to wafers. Herein, for the first time, to address these issues, we show a room-temperature synthesis process employed to produce CsPbBr3 perovskite nanocrystals with two-dimensional (2D) nanosheet features. Due to the unique properties of these 2D nanocrystals, including the 'self-assembly' characteristic, and 'double solvent evaporation inducing self-patterning' strategy are used to generate high-quality patterned thin films in selected areas automatically after-drop-casting, enabling fabrication of high-performance devices without using complex and expensive fabrication processing techniques. The films are free from micro-cracks. In a proof-of-concept experiment, photodetector arrays are used to demonstrate the superior properties of such films. We provide evidence of both high responsivity (9.04 A/W) and high stability across large areas. The photodetectors fabricated on flexible substrate exhibit outstanding photo-response stability. Advanced optical and structural studies reveal the possible mechanism. Our simple and cost-effective method paves the way for the next-generation nanotechnology based on high-performance, cost-effective optoelectronic devices.
关键词： photodetector,Self-assembly,self-patterning,two-dimensional nanosheet,perovskite
更新于2025-09-23 15:23:52
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CsxWO3 nanosheet-coated cotton fabric with multiple functions: UV/NIR shielding and full-spectrum-responsive self-cleaning
摘要： Utilizing fewer functional materials to achieve multifunctional fabrics via facile approaches have been confronting worldwide scientists with an enormous challenge. In this study, a novel multifunctional cotton fabric, combining UV/NIR shielding and full-spectrum-responsive self-cleaning, has been fabricated via self-assembly of CsxWO3 nanosheets based on electrostatic interaction assisted by Poly (diallyldimethylammonium chloride) (PDDA) in aqueous solution. The microstructure of CsxWO3 nanosheets and their self-assembly coating on cotton fabric were characterized and investigated. The functional properties of the CsxWO3-coated cotton fabric, including UV/NIR shielding and photocatalytic self-cleaning were evaluated. The results indicate that the CsxWO3-coated cotton fabric exhibits superb UV/NIR and heat shielding performance with 15.8 °C and 5.9 °C lower than no coverage and coverage by none-treated cotton fabric, respectively. Moreover, the well-coated cotton fabric demonstrates photocatalytic self-cleaning property responsive to the light ranging from UV, Vis to NIR, especially exhibits highly efficient self-cleaning under the respective irritation of full-spectrum, UV and Vis light (color faded completely within 10 h). In summary, the CsxWO3-coated fabrics can achieve multi-functions of UV shielding, heat insulation and self-cleaning by means of a single functional nanomaterial and promise of huge applications in functional textiles.
关键词： full-spectrum self-cleaning,self-assembly coating,UV/NIR shielding,CsxWO3 nanosheets,functional cotton fabric
更新于2025-09-23 15:23:52
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Photooxidase-mimicking nanovesicles with superior photocatalytic activity and stability based on amphiphilic amino acid and phthalocyanine co-assembly
摘要： Enzyme mimics have broad applications in catalysis and can assist elucidation of the catalytic mechanism of natural enzymes. However, challenges arise from the design of catalytic sites, the selection of host molecules and their integration into active three-dimensional structures. Herein, we develop a mimic photooxidase by synergetic molecular self-assembly. 9-Fluorenylmethyloxycarbonyl-L-histidine in combination with phthalocyanine shows efficient co-assembly into nanovesicles with flexibly tunable particle size and membrane thickness. The obtained nanovesicles are capable of reactive oxygen-mediated photosensitive oxidation with improved efficiency and stability. This work highlights the co-assembly of simple building blocks into a supramolecular photocatalyst, which might give insight into possible evolutionary paths of photocatalytic membraneous systems and will allow the facile transfer into photosensitive nanoreactors or artificial organelles.
关键词： self-assembly,photooxidase,amino acids,nanovesicles,phthalocyanines
更新于2025-09-23 15:23:52
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Oligo(ethylene glycol)/alkyl-modified chromophore assemblies for photon upconversion in water
摘要： Molecular self-assembly is a powerful means to construct nanoscale materials with advanced photophysical properties. Although the protection of the photo-excited states from oxygen quenching is a critical issue, it still has been in an early phase of development. In this work, we demonstrate that a simple and typical molecular design for aqueous supramolecular assembly, modification of chromophoric unit with hydrophilic oligo(ethylene glycol) chains and hydrophobic alkyl chains, is effective to avoid oxygen quenching of triplet-triplet annihilation-based photon upconversion (TTA-UC). While a TTA-UC emission is completely quenched when the donor and acceptor are molecularly dispersed in chloroform, their aqueous co-assemblies exhibit a clear upconverted emission in air-saturated water even under extremely low chromophore concentrations down to 40 μM. The generalization of this nano-encapsulation approach offers new functions and applications using oxygen-sensitive species for supramolecular chemistry.
关键词： photon upconversion,photochemistry,oxygen quenching,self-assembly,triplet-triplet annihilation
更新于2025-09-23 15:23:52
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X-Shaped Polycyclic Aromatic Hydrocarbons: Optical Properties and Tunable Assembly Ability
摘要： Although a number of synthetic methodologies have been developed to prepare stable polycyclic aromatic hydrocarbons (PAHs), much less research has been devoted to functionalize the peripheral of molecules to tune the self-assembly ability or introduce functional groups without altering their photophysical properties. Herein, we report twisted “X” shaped molecules prepared through annulation of hexacene with benzoanthracene on the zigzag edge, and an investigation of their photophysical properties and self-assembly properties. The shape-complementary “X” shaped molecules prefer to dimerize, while the π-extension would lead to one dimensional π-stacking. Our findings gave some insights into the design of stable PAHs without disturbing the electronic structures.
关键词： Photophysical properties,Self-assembly,Polycyclic aromatic hydrocarbons,Dimerize
更新于2025-09-23 15:23:52
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Growth and Self-Assembly of Silicon–Silicon Carbide Nanoparticles into Hybrid Worm-Like Nanostructures at the Silicon Wafer Surface
摘要： This work describes the growth of silicon–silicon carbide nanoparticles (Si–SiC) and their self-assembly into worm-like 1D hybrid nanostructures at the interface of graphene oxide/silicon wafer (GO/Si) under Ar atmosphere at 1000 °C. Depending on GO film thickness, spread silicon nanoparticles apparently develop on GO layers, or GO-embedded Si–SiC nanoparticles self-assembled into some-micrometers-long worm-like nanowires. It was found that the nanoarrays show that carbon–silicon-based nanowires (CSNW) are standing on the Si wafer. It was assumed that Si nanoparticles originated from melted Si at the Si wafer surface and GO-induced nucleation. Additionally, a mechanism for the formation of CSNW is proposed.
关键词： nanoparticles,thermal reduction,silicon carbide,graphene oxide,self-assembly,silicon,nanowires
更新于2025-09-23 15:23:52
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Efficient photo-Fenton activity in mesoporous MIL-100(Fe) decorated with ZnO nanosphere for pollutants degradation
摘要： Metal-organic frameworks (MOFs) have received significant interest as a promising photocatalyst for environmental remediation due to its high surface area and porous nature. The small pores (<2 nm) in microporous MOFs help the adsorption of small molecules but limits diffusion and accessing of bigger molecules from MOF cavities, thus preventing their applications in some situation. The aim of this work is to fabricate mesoporous MOF composite with larger pore sizes (>2 nm) and open pore cavities that can provide right pathways for ingoing and outgoing of molecules during catalysis. Herein, we successfully report stable mesoporous MIL-100(Fe) loaded with ZnO NS by an in situ self-assembly method. The prepared samples were characterized by Brunauer–Emmett–Teller (BET) and N2 adsorption-desorption isotherm to study their surface area and porosity. The catalytic performance of mesoporous MIL-100(Fe) was approximately 2-3 order of magnitude more than that of microporous MIL-100(Fe). Such higher catalytic activity in mesoporous MIL-100(Fe) can be ascribed to its mesocellular structure which can improve the molecular diffusion and accessibility inside MOF channels. The charge separation efficiency and photo-Fenton activity of mesoporous MIL-100(Fe) can further be increased by introduction of certain amount of ZnO NS and H2O2. Moreover, the as synthesized sample shows higher photo-Fenton degradation efficiency at lower pH value with certain amount of H2O2. Lastly, the possible catalytic mechanism has been tentatively proposed. This study not only used for the pollutants degradation but also provide useful platform for the application of mesoporous MOFs as an efficient photo-Fenton activity to various other fields.
关键词： Metal-organic framework,ZnO,MIL-100(Fe),self-assembly,photo-Fenton,mesoporous
更新于2025-09-23 15:23:52
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Size and dimension dependent surface-enhanced Raman scattering properties of well-defined Ag nanocubes
摘要： Understanding the role of the morphology and particle–particle interactions on the plasmonic properties is of significant importance for the development of nanomaterials with excellent optical properties. However, the preparation of precisely defined nanomaterials with sizes that span a large range and their controllable self-assembly still remain a great challenge. Here, a multistep seed-mediated method has been established for preparing uniform Ag nanocubes over a broad size range from nanoscale (50 nm) to microscale (1400 nm) and with different hierarchical nanostructures range from “zero-dimension” (“0D”) to “three-dimension” (“3D”). The influence of the size and the interactions between the Ag nanocubes on their surface-enhanced Raman scattering (SERS) properties have been systematically and quantitatively investigated. It is demonstrated through experiments and finite-difference time-domain (FDTD) calculations that the SERS activity is dependent on the matching of the nanocube size to the excitation wavelength. The optimal combinations are 80, 110 and 130 nm nanocubes with respect to 532, 638 and 785 nm excitation wavelength, respectively. Furthermore, the Raman enhancement of the Ag nanocube hierarchical nanostructures increases rapidly from “0D” to “3D”, due to the extra increase of the hot spots that is attributed to the out-of-plane plasmonic coupling realized in the “3D” hierarchical nanostructures. This work clearly illustrates the quantitative role of the size and dimension of Ag nanocubes on their SERS properties and provides fundamental information for the design of advanced nanomaterials with higher SERS sensitivity.
关键词： Silver nanocubes,Self-assembly,Surface-enhanced Raman scattering,Seed-mediated method
更新于2025-09-23 15:23:52
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Fundamental and Practical Limits of Achieving Artificial Magnetism and Effective Optical Medium by Using Self-Assembly of Metallic Colloidal Clusters
摘要： The self-assembly of metallic colloidal clusters (so called plasmonic metamolecules) has been viewed as a versatile, but highly effective approach for the materialization of the metamaterials exhibiting artificial magnetism at optical frequencies (including visible and near infrared (NIR) regimes). Indeed, several proofs of concepts of plasmonic metamolecules have been successfully demonstrated in both theoretical and experimental ways. Nevertheless, this self-assembly strategy has barely been used and still remains an underutilized method. For example, the self-assembly and optical utilization of the plasmonic metamolecules have been limited to the discrete unit of the structure; the materialization of effective optical medium made of plasmonic metamolecules is highly challenging. In this work, we theoretically exploited the practical limits of self-assembly technology for the fabrication of optical magnetic metamaterials.
关键词： colloids,magnetism,self-assembly,plasmonic metamolecules
更新于2025-09-23 15:23:52