Z-Contrast Scanning Transmission Electron Microscopy as a Tool for Interface211 Analysis in Nanocrystal-Polymer Nanocomposites

摘要

We have applied Atomic Number Contrast Scanning Transmission Electron Microscopy211u001e(Z-Contrast STEM) towards the study of colloidal CdSe semiconductor nanocrystals 211u001eembedded in MEH-PPV polymer films as used for a prototype photovoltaic device. 211u001eAtomic resolution imaging reveal both the lateral shape and thickness profile of 211u001enanocrystals embedded in the film. Electron Energy Loss Spectroscopy (EELS) at 211u001esub-nanometer resolution was used to investigate the chemical composition at the 211u001enanocrystal polymer surface. We find evidence for oxygen aggregation at the 211u001einterface, consistent with at maximum one monolayer of surface oxide on the 211u001enanocrystals.