Xianliang Wang

Cu2–xSe Nanocrystals with Localized Surface Plasmon Resonance as Sensitive Contrast Agents for In Vivo Photoacoustic Imaging: Demonstration of Sentinel Lymph Node Mapping

Abstract The promise of a new nanomaterial, Cu(2-x) Se nanocrystals, as a contrast agent for photoacoustic imaging is demonstrated. The Cu(2-x) Se nanocrystals exhibit strong optical absorption at near infrared wavelengths that can efficiently penetrate tissue. In vivo photoacoustic tomography using this nanomaterial as the contrast agent provides clear three-dimensional resolution of a sentinel lymph node in a rat model.

Enhanced Upconversion Luminescence in Yb3+/Tm3+-Codoped Fluoride Active Core/Active Shell/Inert Shell Nanoparticles through Directed Energy Migration

The luminescence efficiency of lanthanide-doped upconversion nanoparticles is of particular importance for their embodiment in biophotonic and photonic applications. Here, we show that the upconversion luminescence of typically used NaYF4:Yb3+30%/Tm3+0.5% nanoparticles can be enhanced by ~240 times through a hierarchical active core/active shell/inert shell (NaYF4:Yb3+30%/Tm3+0.5%)/NaYbF4/NaYF4 design, which involves the use of directed energy migration in the second active shell layer. The resulting active core/active shell/inert shell nanoparticles are determined to be about 11 times brighter than that of well-investigated (NaYF4:Yb3+30%/Tm3+0.5%)/NaYF4 active core/inert shell nanoparticles when excited at ~980 nm. The strategy for enhanced upconversion in Yb3+/Tm3+-codoped NaYF4 nanoparticles through directed energy migration might have implications for other types of lanthanide-doped upconversion nanoparticles.

Effective strategies for stabilizing sulfur for advanced lithium–sulfur batteries

The lithium-ion battery, with a relatively small energy density of ∼250 W h kg−1, has dominantly powered many devices requiring small energy demands. However, there remains a need for a cheaper and smaller type of battery with higher energy density for energy-intensive storage purposes in the automotive, aircraft, and household energy sectors. With its higher specific capacity (1675 mA h g−1) and lower costs, the lithium–sulfur (Li–S) battery represents the most promising next generation battery. The main focus of scientific inquiry surrounding Li–S batteries lies at the cathode, where sulfur chemically bonds to lithium. Current challenges pertaining to the high performance cathode such as the dissolution of sulfur into the electrolyte and electrode volume changes are highlighted. This review focuses on recent developments in the last three years of various sulfur integration methods at the cathode that result in improved electrochemical performance, increased energy density, cyclic stability, and a higher capacity over the mainstream lithium-ion battery. In particular, the most recent approaches were systematically examined and compared including the use of carbon and non-carbon composites to stabilize sulfur. Ideal material hosts for sulfur atoms in the cathode for outstanding Li–S batteries were outlined and thoroughly discussed. Critical understanding and relevant knowledge were summarized aiming to provide general guidance for rational design of high-performance cathodes for advanced Li–S batteries.

High-definition conductive silver patterns on polyimide film via an ion exchange plating method

In this work, we developed a new ion exchange plating (IEP) method that is different to traditional electrochemical plating or electroless plating techniques. A variety of silver patterns were prepared by using the IEP technique as demonstrated in this work. The key factors to the definition and the conductive performance of silver patterns were systematically studied. Mechanisms of the formation of the conductive silver patterns was studied as well. A new model was established for elucidating the deposition process. Importantly, using this IEP method coupled with mask technology, double-sided interconnected conductive silver patterns on polyimide substrates were successfully fabricated with high definition. This new technology will provide a unique capability to fabricate double-sided or multi-sided interconnection for next generation printed circuit board (PCB).