?In-situ? XAFS and SAXS study of the kinetics of growth of Au nanowires

PSCHUNDER, FERNANDO; JOSE MARTIN RAMALLO LOPEZ; GIOVANETTI, LISANDRO J; CRISTINA HUCK-IRIART; FÉLIX GREGORIO REQUEJO; CRISTINA HOPPE

Venecia

Workshop; CeNS Workshop 2017 ?Design and Control of NanoSystems?; 2017

Centro de Nanociencia (CeNS) de la Ludwig Maximilians Universität (Munich, Alemania)

The slow reduction of Au-oleylamine(Au-OY) complexby tri-isopropil-silano(TIPS) results in the formation of ultrathin (~2 nm diameter) gold nanowires (AuNWs).In this work we studied the kinetics of growth of the AuNWsby means of ?in situ? measurements usingX-ray Absorption Fine Structure (XAFS) Spectroscopy at the Au L3 edge and Small Angle X-rayScattering (SAXS). Our results show that the AuNWsformation proceeds in two steps: first Au is reduced from +3 to +1 forminglinear complexes and during a second step Au is reducedfrom Au+1 to Au0fromnonmetallic spherical micelle like structures to AuNWs. Results obtained by transmissionelectron microscopy (TEM) would suggest the possible occurrence of an orientedattachment mechanism as responsible for the formation of AuNWs.SAXS shows the assembly of AuNWs into hexagonal superlatticeswhose stability is affected by the OY?s carbonatationstate and the lattice parameter is consistent with a bilayer of OYattachedat the surface of the AuNWs.