Synthesis, Characterization, and Application of Ultrasmall Nanoparticles

Abstract

Nanomaterials in the size range of 3–50 nm have received increased attention in the last few decades because they exhibit physical properties that are intermediate to those of individual molecules and bulk materials. Similarly, ultrasmall nanoparticles (USNPs), with sizes in the 1–3 nm range, exhibit unique properties distinct from those of free molecules and larger-sized nanoparticles. These properties are greatly sensitive to both the composition and size of the particles, and thus, the ability to control the synthesis for both of these variables is of paramount importance. This review summarizes various methods for the synthesis of USNPs of metals, metal oxides, and metal chalcogenides as well as recent advances in the development of unique characterization methods for these USNPs. Last is a discussion of several novel applications of USNPs in biomedical imaging, catalysis, and semiconductor development, all of which benefit from the large surface-to-volume ratio and/or other characteristic properties inherent in USNPs.

A facile synthesis of highly stable and luminescent Ag clusters: a steady-state and time-resolved spectroscopy study

“…Strikingly, the addition of NaCl to the solvent is associated with a small red shift of the PL emission maximum of the A-AgPVP clusters. Moreover, the addition of a reducing agent such as NaBH 4 or of an oxidizing agent like H 2 O 2 to the A-AgPVP cluster colloid was not observed to alter the spectral features of their PL emission and UV/Vis absorption spectra. These experimental results prove both the high stability of the Ag clusters and the absence of any Ag + ions in the solution.…”

Mechanistic Study of the Formation of Bright White Light-Emitting Ultrasmall CdSe Nanocrystals: Role of Phosphine Free Selenium Precursors

“…Almost all previous studies have exclusively used trialkylphosphine chalcogenides (R3P=E; E= S, Se, Te) for the production of metal chalocogenide QDs, and from spectroscopic analysis it was proposed that "magic-sized" nanocrystals (MSNs) (<1.5 nm in diameter) are formed as key intermediates, which undergo further growth to form QDs. [15][16][17][18] Because of high reaction temperature, the appearance and disappearance of these intermediate nanocrystals were very rapid. Thus they have not been isolated and characterized, and even their structural properties remain elusive.…”

Colloidal Magnetic Heterostructured Nanocrystals with Asymmetric Topologies: Seeded-Growth Synthetic Routes and Formation Mechanisms

“…Colloidal approaches, which enable governing the thermodynamics and kinetics of nucleation, growth, and crystallization of solids in liquid media Kwon and Hyeon, 2008;Erdemir et al, 2009;Wang et al, 2015), have demonstrated to be powerful synthetic routes to precisely phase-engineered NCs for a huge materials library across diverse size-morphological regimes Jun et al, 2006;Park et al, 2007;Cozzoli, 2008;Baghbanzadeh et al, 2011;Kim et al, 2013;Yang et al, 2013;Lhuillier et al, 2015). Recently, to meet the raising demand for intelligent nanosystems capable to exhibit enhanced, diversified, or even completely unprecedented properties and capabilities for multitask applications, synthetic nanochemistry research has opened up new horizons in the design, creation, and mastering of increasingly complex NC-based assemblies and architectures.…”