title: BaO clusters on MgO nanocubes: a quantitative analysis of optical-powder properties.
abstract: Uniformly sized and shaped nanoparticles are well suited for the quantitative characterization of optical-powder properties. For the first time, quantum yields related to photoluminescence emissions that originate from the photoexcitation of MgO nanocube corners and edges are measured. In addition, the surfaces of these nanoparticles are doped with submonolayer barium, which oxidizes during adsorption onto the MgO nanocrystal surfaces and transforms in O(2) atmosphere into BaO. UV-Vis diffuse reflectance and photoluminescence spectroscopy is employed to explore whether 10(-3) monolayer equivalents of these dopants affect the MgO specific optical properties. Surface-admixed BaO produces additional absorption and photoluminescence emission features but does not significantly affect those specific to MgO nanocubes. On this basis the number of optically active sites that can be sampled inside a powder of alkaline earth oxide nanoparticles using a standard spectrometer system is estimated.
authors.affiliation: Institute of Materials Chemistry, Vienna University of Technology, Veterinärplatz 1/GA, Vienna 1210, Austria.
authors.forename: Andreas
authors.initials: A
authors.lastname: Sternig
authors.forename: Markus
authors.initials: M
authors.lastname: Müller
authors.forename: Mark
authors.initials: M
authors.lastname: McCallum
authors.forename: Johannes
authors.initials: J
authors.lastname: Bernardi
authors.forename: Oliver
authors.initials: O
authors.lastname: Diwald
mesh_terms: D017609:Barium Compounds / Q000737:chemistry*; D008277:Magnesium Oxide / Q000737:chemistry*; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D055620:Optical Phenomena; D010087:Oxides / Q000737:chemistry*; D011208:Powders; D013050:Spectrometry, Fluorescence; D013499:Surface Properties; D014466:Ultraviolet Rays
chemical_list: D017609:Barium Compounds; D010087:Oxides; D011208:Powders; D008277:Magnesium Oxide; C077606:barium oxide