| Maximum Entropy and Pixon reconstructed Z-Contrast Scanning Transmission Electron Micrograph (Z-STEM) of a CdSe (cadmium selenide) nanocrystal embedded in MEH-PPV polymer. The Image was obtained on the VG HB603 STEM in the Electron Microscopy Group, Oakridge Nat. Lab., Stephen Pennycook, PI. The nanocrystal composite sample was prepared in the group of Prof. Sandy Rosenthal, Vanderbilt University. Tadd Kippeny: nanocrystal synthesis; Meg Erwin: polymer synthesis; Peter Nellist: assistance with STEM operation; Andreas Kadavanich: fabrication of the composite, microscopy. Bright objects are Cd atoms. Darker adjacent objects are Se atoms roughly 1.5 Angstrons away. CdSe pairs are separated by roughly 3.6 Angstroms. PSF FWHM is pproximately 1.5 Angstroms and is sampled by 11 to 12 pixels. The Max Entropy image shows a multitude of spurious artifacts and strongly over-resolves the image. The Pixon method robustly rejects false structures and accurately displays the true resolution achieved by the data. |
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