title: Two step formation of metal aggregates by surface X-ray radiolysis under Langmuir monolayers: 2D followed by 3D growth.
abstract: In order to form a nanostructured metallic layer below a Langmuir monolayer, radiolysis synthesis was carried out in an adapted geometry that we call surface X-ray radiolysis. In this procedure, an X-ray beam produced by a synchrotron beamline intercepts the surface of an aqueous metal-ion solution covered by a Langmuir monolayer at an angle of incidence below the critical angle for total internal reflection. Underneath the organic layer, the X-ray beam induces the radiolytic synthesis of a nanostructured metal-organic layer whose ultrathin thickness is defined by the vertical X-ray penetration depth. We have shown that increasing the X-ray flux on the surface, which considerably enhances the kinetics of the silver layer formation, results in a second growth regime of silver nanocrystals. Here the formation of the oriented thin layer is followed by the appearance of a 3D powder of silver clusters.
authors.affiliation: Sorbonne Universités, Université Pierre et Marie Curie (Paris 06), Institut des NanoSciences de Paris, CNRS-UMR 7588, 4 place Jussieu, 75005 Paris, France.
authors.forename: Smita
authors.initials: S
authors.lastname: Mukherjee
authors.affiliation: Sorbonne Universités, Université Pierre et Marie Curie (Paris 06), Institut des NanoSciences de Paris, CNRS-UMR 7588, 4 place Jussieu, 75005 Paris, France; Faculté des Sciences Fondamentales et Biomédicales, Université Paris Descartes, 45 rue des Saints Peres, 75006 Paris, France.
authors.forename: Marie-Claude
authors.initials: MC
authors.lastname: Fauré
authors.affiliation: Sorbonne Universités, Université Pierre et Marie Curie (Paris 06), Institut des NanoSciences de Paris, CNRS-UMR 7588, 4 place Jussieu, 75005 Paris, France; Faculté des Sciences Fondamentales et Biomédicales, Université Paris Descartes, 45 rue des Saints Peres, 75006 Paris, France; Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, 91192 Gif-sur-Yvette, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Goldmann
authors.affiliation: Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, 91192 Gif-sur-Yvette, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Fontaine
keywords: GIXD; Langmuir monolayers; TXRF; X-ray radiolysis; silver clusters