Print Email Facebook Twitter Surfaces of colloidal PbSe nanocrystals probed by thin-film positron annihilation spectroscopy Title Surfaces of colloidal PbSe nanocrystals probed by thin-film positron annihilation spectroscopy Author Chai, L. Al-Sawai, W. Gao, Y. Houtepen, A.J. Mijnarends, P.E. Barbiellini, B. Schut, H. Van Schaarenburg, L.C. Van Huis, M.A. Ravelli, L. Egger, W. Kaprzyk, S. Bansil, A. Eijt, S.W.H. Faculty Applied Sciences Department RST/Radiation, Science and Technology Date 2013-08-16 Abstract Positron annihilation lifetime spectroscopy and positron-electron momentum density (PEMD) studies on multilayers of PbSe nanocrystals (NCs), supported by transmission electron microscopy, show that positrons are strongly trapped at NC surfaces, where they provide insight into the surface composition and electronic structure of PbSe NCs. Our analysis indicates abundant annihilation of positrons with Se electrons at the NC surfaces and with O electrons of the oleic ligands bound to Pb ad-atoms at the NC surfaces, which demonstrates that positrons can be used as a sensitive probe to investigate the surface physics and chemistry of nanocrystals inside multilayers. Ab initio electronic structure calculations provide detailed insight in the valence and semi-core electron contributions to the positron-electron momentum density of PbSe. Both lifetime and PEMD are found to correlate with changes in the particle morphology characteristic of partial ligand removal. To reference this document use: http://resolver.tudelft.nl/uuid:deb88703-bd97-4af6-bae9-55172eac49a2 DOI https://doi.org/10.1063/1.4818001 Publisher American Institute of Physics ISSN 2166-532X Source https://doi.org/10.1063/1.4818001 Source APL Materials, 1 (2), 2013 Part of collection Institutional Repository Document type journal article Rights © 2013 The Author(s)Creative Commons BY Files PDF Eijt_2013_.pdf 749.54 KB Close viewer /islandora/object/uuid:deb88703-bd97-4af6-bae9-55172eac49a2/datastream/OBJ/view