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Nanoscintillators (nanocrystals with X‐ray scintillation performance) lay a fundamental for their practical application in high‐resolution and low‐dose medical examination due to their excellent photoelectric properties. The optical properties and scintillation performance of nanocrystals (NCs) can be significantly affected by adjusting their size. However, the mechanism of the size effect of NCs on optical properties and X‐ray scintillation performance has not been revealed. Here, a mathematical model and experimental results are combined to demonstrate the impact of the size of NCs on their scintillation performance. The results show that the surface area and volume of NCs exhibit a positive and negative impact on the change rate of the bandgap, respectively. This model further verifies that the photoluminescence quantum yield of NCs decreases with the decrease of their size, and their light yield is remarkably affected by the size of NCs. Overall, this work provides some enlightenment for researchers to design NCs with the appropriate size for their applications in high‐performance X‐ray scintillation. [ABSTRACT FROM AUTHOR]

The self-assembly of colloidal nanoparticles has made it possible to bridge the nanoscopic and macroscopic worlds and to make complex nanostructures. The nanoparticle-mediated assembly enables many potential applications, from biodetection and nanomedicine to optoelectronic devices. Properties of assembled materials are determined not only by the nature of nanoparticle building blocks, but also by spatial positions of nanoparticles within the assemblies. A deep understanding of nanoscale interactions between nanoparticles is a prerequisite to controlling nanoparticle arrangement during assembly. In this review, we present an overview of interparticle interactions governing their assembly in a liquid phase. Considerable attention is devoted to examples that illustrate nanoparticle assembly into ordered superstructures using different types of building blocks, including plasmonic nanoparticles, magnetic nanoparticles, lanthanide-doped nanophosphors, and quantum dots. We also cover the physicochemical properties of nanoparticle ensembles, especially those arising from particle coupling effects. We further discuss future research directions and challenges in controlling self-assembly at a level of precision that is most crucial to technology development. [ABSTRACT FROM AUTHOR]

Probing the nature of nanocrystalline materials such as the surface state, crystal structure, morphology, composition, optical and magnetic characteristics is a crucial step in understanding their chemical and physical performance and in exploring their potential applications. Upconversion nanocrystals have recently attracted remarkable interest due to their unique nonlinear optical properties capable of converting incident near-infrared photons to visible and even ultraviolet emissions. These optical nanomaterials also hold great promise for a broad range of applications spanning from biolabeling to optoelectronic devices. In this review, we overview the instrumentation techniques commonly utilized for the characterization of upconversion nanocrystals. A considerable emphasis is placed on the analytical tools for probing the optical properties of the luminescent nanocrystals. The advantages and limitations of each analytical technique are compared in an effort to provide a general guideline, allowing optimal conditions to be employed for the characterization of such nanocrystals. Parallel efforts are devoted to new strategies that utilize a combination of advanced emerging tools to characterize such nanosized phosphors. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, we report on the synthesis of size-dependent blue luminescent CdS nanocrystals by using a new nonhydrolytic single-source molecular method. The size of the synthesized CdS nanocrystals could be easily controlled by adjusting the ratio of reaction sources under inert atmosphere. The studies on the optical properties reveal an obvious size-dependent photoluminescence characteristic of the synthesized nanocrystals. [Copyright &y& Elsevier]

Abstract: Metal (Cd, Cu, and Ni) sulfide nanocrystals have been synthesized by a single-source molecular precursor method. The size of the nanocrystals can be well controlled by adjusting the ration of the oleylamine and precursors. This synthesis may represent a general approach towards metal sulfide nanocrystals, which may promise both adequate academic and practical interest in the development of synthetic methodologies for inorganic nanocrystals, and in the expansion of their potential applications. [Copyright &y& Elsevier]