Superlattices of silver nanoparticles passivated by mercaptan

He, Shengtai; Yao, Jiannian; Xie, Sishen; Gao, Hongjun; Pang, Shijin

doi:10.1088/0022-3727/34/24/301

Cited by 38 publications

(23 citation statements)

References 22 publications

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“…The different peaks originate from the (111), ( 200), ( 220), (311) and (222) planes of Ag NPs which perfectly matches with the JCPDS card number 4-0783. 48,49 All the diffraction peaks conrm the presence of face-centered cubic (fcc) structure of crystalline Ag NPs. In Fig.…”

Section: X-ray Diffraction (Xrd) Analysismentioning

confidence: 99%

In situ formation of curcumin stabilized shape-selective Ag nanostructures in aqueous solution and their pronounced SERS activity

Kundu

Nithiyanantham

2013

RSC Adv.

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In-situ formation of shape-selective silver nanoparticles (Ag NPs) inaqueous solution has been demonstrated just within an hour time. Ag NPs were synthesized by the reduction of Ag(I) ions in presence of a new reducing and stabilizing reagent, curcumin under continuous stirring and heating at 80 °C. Different size and shaped Ag NPs like small and large spheres, nanowires and anisotropic nano-flakes are formed just by tuning the molar ratio of curcumin to Ag(I) ions and controlling the other reaction parameters. The mechanism of formation, the role of curcumin and other reaction parameters for the formation of shape-selective Ag NPs has been examined in details. The different shaped Ag NPs has been successfully employed for the application in surface enhanced Raman spectroscopy (SERS) study using methylene blue (MB) as Raman probe. The shape effect of the NPs has been examined in-detail and the corresponding SERS enhancement factor (EF) values have been calculated. The observed EF values are in the range ~ 10 6 to 10 7 . It was found that the anisotropic nano-flake structure have the highest EF compared to other shapes. The synthesis process is straightforward, simple, reproducible, cost effective and robust. The synthesized Ag NPs are stable for more than two months while kept in a sealed bottle in refrigerator. In futuristic, the present process might be helpful for the synthesis of other types of nanomaterials in a small time scale with larger yield. Moreover, the high EF Recently, Au NPs with nanorods, nanowires, and nano triangles have been applied as SERS substrate to improve the sensitivity and reliability of conventional chemical and biological sensing. 57 Although, most of the nanomaterials used are not either uniform in shape or used a mixture of different size or shaped particles. Moreover, most of the cases, due to presence of surfactant or other capping agents on the NPs surface reduce their efficiency.In our present SERS study, we have synthesized four different sizes and shaped Ag NPs without addition of any seed particles or surfactant. We used small and larger size Ag spheres, Ag nanowires and Ag nano-flakes for study their shape effect on SERS. For comparison

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Section: X-ray Diffraction (Xrd) Analysismentioning

confidence: 99%

In situ formation of curcumin stabilized shape-selective Ag nanostructures in aqueous solution and their pronounced SERS activity

Kundu

Nithiyanantham

2013

RSC Adv.

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“…Nanoparticle (NP) superlattices (NPSLs) are three-dimensional arrays of NPs stabilized by weak interactions. − The fabrication of NPSLs, empowered by fast advances in the synthesis of NPs of complex shapes and tunable surface chemistry, represents an outstanding opportunity for the design of novel materials with potential applications in electronics, photonics, and plasmonic devices. − Nanoparticle building blocks can be made from diverse materials, including metals, ,− dielectrics, and semiconductors. − The surface chemistry of these NPs can be tuned independently of the core composition by ligand exchange. For example, this procedure enables the preparation of NPSLs from NPs coated by DNA strands − and polymers. − However, most examples of NPSLs still involve NPs capped by the native ligands used to passivate them during synthesis, such as n- alkanethiols for metal nanoparticles ,, or alkyl-teminated carboxylic acids for semiconductor quantum dots. , These ligands form a soft corona around the inorganic core, which grants solubility before crystallization. Moreover, upon slow evaporation of the solvent, corona–corona interactions dictate the forces between neighboring NPs and drive the formation of the superlattice.…”

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confidence: 99%

The Phase Behavior of Nanoparticle Superlattices in the Presence of a Solvent

Missoni

Tagliazucchi

2020

ACS Nano

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Superlattices of nanoparticles coated by alkyl-chain ligands are usually prepared from a stable solution by evaporation, therefore the pathway of superlattice self-assembly critically depends on the amount of solvent present within it. This work addresses the role of the solvent on the structure and the relative stability of the different supercrystalline phases of single-component superlattices (simple cubic, body-centered cubic (BCC), face-centered cubic (FCC), and hexagonal close-packed). The study is performed with a molecular theory for nanoparticle superlattices introduced in this work, which predicts the structure and thermodynamics of the supercrystals explicitly treating the presence and molecular details of the solvent and the ligands. The theory predicts a FCC–BCC transition with decreasing solvent content due to the competition between the translational entropy of the solvent and the entropy and internal energy of the ligands. This result provides an explanation for recent experimental observations by in situ X-ray scattering, which reported a FCC–BCC transition during solvent evaporation. The theory also predicts the effects of the length and surface coverage of the ligands and the radius of the core on the phase behavior in agreement with experimental evidence and previous molecular dynamics simulations. These results validate the use of the dimensionless softness parameter λ (ratio of ligand length to core radius) to predict the phase behavior of wet superlattices. Our results stress the importance of explicitly considering the presence of the solvent in order to reach a complete picture of the mechanisms that mediate the self-assembly of nanoparticle superlattices.

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“…S3 †)). 27 This reveals that the thiol part remains intact upon being covered with titania. The peaks at 464.4 and 458.8 eV in Fig.…”

Section: Resultsmentioning

confidence: 95%