Colloidal metal‐halide perovskite nanocrystals (MHP NCs) are gaining significant attention for a wide range of optoelectronics applications owing to their exciting properties, such as defect ...tolerance, near‐unity photoluminescence quantum yield, and tunable emission across the entire visible wavelength range. Although the optical properties of MHP NCs are easily tunable through their halide composition, they suffer from light‐induced halide phase segregation that limits their use in devices. However, MHPs can be synthesized in the form of colloidal nanoplatelets (NPls) with monolayer (ML)‐level thickness control, exhibiting strong quantum confinement effects, and thus enabling tunable emission across the entire visible wavelength range by controlling the thickness of bromide or iodide‐based lead‐halide perovskite NPls. In addition, the NPls exhibit narrow emission peaks, have high exciton binding energies, and a higher fraction of radiative recombination compared to their bulk counterparts, making them ideal candidates for applications in light‐emitting diodes (LEDs). This review discusses the state‐of‐the‐art in colloidal MHP NPls: synthetic routes, thickness‐controlled synthesis of both organic–inorganic hybrid and all‐inorganic MHP NPls, their linear and nonlinear optical properties (including charge‐carrier dynamics), and their performance in LEDs. Furthermore, the challenges associated with their thickness‐controlled synthesis, environmental and thermal stability, and their application in making efficient LEDs are discussed.
This review provides a comprehensive overview of the research progress and challenges associated with thickness‐controlled synthesis, stability, surface passivation, doping, optical (linear and nonlinear) properties of both organic and organic–inorganic hybrid lead and lead‐free halide perovskite nanoplatelets along with recent progress on their application to light‐emitting diodes.
The versatility of wet chemical methods has rendered them extremely popular for the preparation of metal nanoparticles with tailored size and shape. This Feature Article reviews the use of ...N,N‐dimethylformamide (DMF) for the reduction of metal salts, mainly Au and Ag, while also acting as a solvent. Apart from describing the ability of DMF to reduce metal salts, the effect of different parameters, such as the concentration of capping agent and metal precursors, the presence of preformed seeds acting as catalysts or their crystalline structure, on particle morphology are analyzed. Published reports on the use of different capping agents are summarized, with particular emphasis on the role of poly(vinylpyrrolidone) to determine the morphology of the particles. Finally, a brief overview is provided on the modulation of the optical response in DMF‐based metal nanoparticle colloids with tunable size and shape.
The reduction of metal salts by N,N‐dimethylformamide leads to the formation of metal colloids, with a variety of surface functionalities and particle morphologies, thus allowing a fine modulation of their optical response.
This work focuses on the systematic investigation of the shape, size, and composition‐controlled synthesis of perovskite nanocrystals (NCs) under inert gas‐free conditions and using pre‐synthesized ...precursor stock solutions. In the case of CsPbBr3 NCs, we find that the lowering of reaction temperature from ∼175 to 100 °C initially leads to a change of morphology from bulk‐like 3D nanocubes to 0D nanocubes with 3D‐quantum confinement, while at temperatures below 100 °C the reaction yields 2D nanoplatelets (NPls) with 1D‐quantum confinement. However, to our surprise, at higher temperatures (∼215 °C), the reaction yields CsPbBr3 hexapod NCs, which have been rarely reported. The synthesis is scalable, and their halide composition is tunable by simply using different combinations of precursor solutions. The versatility of the synthesis is demonstrated by applying it to relatively less explored shape‐controlled synthesis of FAPbBr3 NCs. Despite the synthesis carried out in the air, both the inorganic and hybrid perovskite NCs exhibit nearly‐narrow emission without applying any size‐selective separation, and it is precisely tunable by controlling the reaction temperature.
The morphology of both inorganic and hybrid halide perovskite nanocrystals is tunable from 3D nanocubes with no‐confinement to 0D nanocubes and 2D nanoplatelets with 3D and 1D‐quantum confinement, respectively by a decrease of the reaction temperature in the hot‐plate approach under inert gas‐free conditions. The synthesis is scalable, and their halide composition is tunable by simply using different combinations of precursor stock solutions.
A single nanoplatform integrating laser‐induced heat generation by gold nanoparticles and temperature sensing up to 2000 K via (Gd,Yb,Er)2O3 nanorods is demonstrated, which presents considerable ...potential for nanoscale photonics and biomedicine. Blackbody emission is ascertained from the temperature increment with AuNP concentration, emission color coordinates as a function of the laser pump power, and Planck's law of blackbody radiation.
A robust and reproducible methodology to prepare stable inorganic nanoparticles with chiral morphology may hold the key to the practical utilization of these materials. An optimized chiral growth ...method to prepare fourfold twisted gold nanorods is described herein, where the amino acid cysteine is used as a dissymmetry inducer. Four tilted ridges are found to develop on the surface of single‐crystal nanorods upon repeated reduction of HAuCl4, in the presence of cysteine as the chiral inducer and ascorbic acid as a reducing agent. From detailed electron microscopy analysis of the crystallographic structures, it is proposed that the dissymmetry results from the development of chiral facets in the form of protrusions (tilted ridges) on the initial nanorods, eventually leading to a twisted shape. The role of cysteine is attributed to assisting enantioselective facet evolution, which is supported by density functional theory simulations of the surface energies, modified upon adsorption of the chiral molecule. The development of R‐type and S‐type chiral structures (small facets, terraces, or kinks) would thus be non‐equal, removing the mirror symmetry of the Au NR and in turn resulting in a markedly chiral morphology with high plasmonic optical activity.
Fourfold twisted Au nanorods can be prepared via chiral seeded growth, using cysteine as a chiral inducer. A high dissymmetry factor is obtained and electromagnetic simulations show chiral plasmon modes with largely asymmetric near‐field enhancement. The mechanism involved in chiral growth is related with cysteine‐induced enantioselective development of chiral facets.
Plasmonic metal‐organic frameworks are composite nanoparticles comprising plasmonic metal nanoparticles (NPs) embedded within a metal‐organic framework (MOF) matrix. As a result, not only the ...functionalities of the individual components are retained, but synergistic effects additionally provide improved chemical and physical properties. Recent progress in plasmonic MOFs has demonstrated the potential for nanofabrication and various nanotechnology applications. Synthetic challenges toward plasmonic MOFs have been recently addressed, resulting in new opportunities toward practical applications, such as surface‐enhanced Raman scattering, therapy, and catalysis. The impact of key parameters (thermodynamic vs. kinetic) on the synthetic pathways of plasmonic MOFs is reviewed, while providing insight into related progress toward structure‐derived applications.
Plasmonic metal‐organic frameworks hybrid nanocomposites feature improved chemical and physical properties, as compared with their individual components, due to synergistic performance. These materials show excellent opportunities toward practical applications, such as surface‐enhanced Raman scattering, therapy, and catalysis.
In this minireview, we summarize current research dealing with the combination of noble‐metal nanoparticles and different families of supramolecular macrocycles (cyclodextrins, cucurbitnurils, ...calixarenes, and pillarnarenes). We intended to select relevant publications on the synthesis of noble‐metal nanoparticles with macrocycles acting as capping agents or/and reducing agents, as well as on the post‐synthetic metal‐nanoparticle modification with macrocycles. We also discuss strategies in which supramolecular chemistry is applied to direct the self‐assembly of nanoparticles and formation of polymer composites. We finally describe the main applications of these materials in various fields.
Nanoparticles and macrocycles: Recent literature regarding the combination of supramolecular macrocycles and metal nanoparticles is reviewed, with particular emphasis on the synthesis, surface modification and assembly, as well as the potential applications of the obtained nanocomposites (SERS = surface‐enhanced Raman spectroscopy).
Advances in Plasmonic Sensing at the NIR-A Review S S Dos Santos, Paulo; M M M de Almeida, José; Pastoriza-Santos, Isabel ...
Sensors (Basel, Switzerland),
03/2021, Letnik:
21, Številka:
6
Journal Article
Recenzirano
Odprti dostop
Surface plasmon resonance (SPR) and localized surface plasmon resonance (LSPR) are among the most common and powerful label-free refractive index-based biosensing techniques available nowadays. ...Focusing on LSPR sensors, their performance is highly dependent on the size, shape, and nature of the nanomaterial employed. Indeed, the tailoring of those parameters allows the development of LSPR sensors with a tunable wavelength range between the ultra-violet (UV) and near infra-red (NIR). Furthermore, dealing with LSPR along optical fiber technology, with their low attenuation coefficients at NIR, allow for the possibility to create ultra-sensitive and long-range sensing networks to be deployed in a variety of both biological and chemical sensors. This work provides a detailed review of the key science underpinning such systems as well as recent progress in the development of several LSPR-based biosensors in the NIR wavelengths, including an overview of the LSPR phenomena along recent developments in the field of nanomaterials and nanostructure development towards NIR sensing. The review ends with a consideration of key advances in terms of nanostructure characteristics for LSPR sensing and prospects for future research and advances in this field.
Chiral transition metal oxide nanoparticles (CTMOs) are attracting a lot of attention due to their fascinating properties. Nevertheless, elucidating the chirality induction mechanism often remains a ...major challenge. Herein, the synthesis of chiral cobalt oxide nanoparticles mediated by histidine (Co3O4@L‐His and Co3O4@D‐His for nanoparticles synthesized in the presence of L‐ and D‐histidine, respectively) is investigated. Interestingly, these CTMOs exhibit remarkable and tunable chiroptical properties. Their analysis by x‐ray photoelectron, Fourier transform infrared, and ultraviolet‐visible absorption spectroscopy indicates that the ratio of Co2+/Co3+ and their interactions with the imidazole groups of histidine are behind their chiral properties. In addition, the use of chiral Co3O4 nanoparticles for the development of sensitive, rapid, and enantioselective circular dichroism‐based sensors is demonstrated, allowing direct molecular detection and discrimination between cysteine or penicillamine enantiomers. The circular dichroism response of the chiral Co3O4 exhibits a limit of detection and discrimination of cysteine and penicillamine enantiomers as low as 10 µm. Theoretical calculations suggest that the ligand exchange and the coexistence of both species adsorbed on the oxide surface are responsible for the enantiomeric discrimination. This research will enrich the synthetic approaches to obtain CTMOs and enable the extension of the applications and the discovery of new chiroptical properties.
The effect of chemical states on the chirality origin and chiroptical activity of chiral cobalt oxide nanoparticles mediated by histidine (Co3O4@His NPs) is investigated theoretically and experimentally. In addition, the chiral Co3O4@His NPs are applied for the enantiomeric discrimination and quantification of cysteine and penicillamine enantiomers.
Organizing nanoparticles (NPs) into periodic structures is a central goal in materials science. Despite progress in the last decades, it is still challenging to produce macroscopic assemblies ...reliably. In this work, the analysis of the pervaporation‐induced organization of gold octahedra into supercrystals within microfluidic channels using a combination of X‐ray scattering techniques and FIB‐SEM tomography is reported. The results reveal the formation of a single‐domain supercrystal with a monoclinic C2/m symmetry and long‐range order extending over the dimensions of the microfluidic channel, covering at least 1.7 × 0.3 mm2. Time‐resolved small angle X‐ray scattering analysis shows that the formation of the superlattice involves an accumulation of the NPs within the channel before the nucleation and growth of the supercrystal. The orientation of the crystal remains unchanged during its formation, suggesting a growth mechanism directed by the channel interface. Together, these results show the potential application of the pervaporation strategy to providing spatially determined control over NP crystallization, which can be used for the rational fabrication of nanomaterial architectures.
A pervaporation‐induced self‐assembly strategy is used to obtain supercrystals of gold octahedra in a microfluidic channel. Supercrystal analysis by small angle X‐ray scattering and scanning electron microscopy tomography indicates the formation of extended superlattices with a monoclinic C/2m crystalline symmetry. The size of the supercrystals is among the largest reported to date for plasmonic nanoparticle, covering at least 1.7 × 0.3 mm2.
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