Complementary microscopy techniques applied for optimizing the structure and performance of graphene-based hybrids.

To improve the performance of graphene and to extend its potential applications, one of the most effective efforts is to hybridize graphene with one or more metal/metal oxide nanocrystals (NCs). In this paper, we demonstrate the complementary techniques of X-ray diffraction, high resolution electron microscopy (HREM), energy-dispersive X-ray spectroscopy (EDX), and energy-filtered transmission electron microscopy (EFTEM), which enables us to optimize the synthetic conditions, improve the quality of attached NCs, and tailor the performance of graphene-based hybrids for green energy related applications. Specifically, we explored the EFTEM technique to characterize two graphene-based composites.

One-step Melt Synthesis of Water Soluble, Photoluminescent, Surface-Oxidized Silicon Nanoparticles for Cellular Imaging Applications.

We have developed a versatile, one-step melt synthesis of water-soluble, highly emissive silicon nanoparticles using bi-functional, low-melting solids (such as glutaric acid) as reaction media. Characterization through transmission electron microscopy, selected area electron diffraction, X-ray photoelectron spectroscopy, and Raman spectroscopy shows that the one-step melt synthesis produces nanoscale Si cores surrounded by a silicon oxide shell. Analysis of the nanoparticle surface using FT-IR, zeta potential, and gel electrophoresis indicates that the bi-functional ligand used in the one-step synthesis is grafted onto the nanoparticle, which allows for tuning of the particle surface charge, solubility, and functionality.