Structural and electronic analysis of the atomic scale nucleation of Ag on α-Ag2WO4 induced by electron irradiation

Abstract

In this work, we utilise a combination of theory, computation and experiments to understand the early events related to the nucleation of Ag filaments on α-Ag2WO4 crystals, which is driven by an accelerated electron beam from an electron microscope under high vacuum. The growth process and the chemical composition and elemental distribution in these filaments were analysed in depth at the nanoscale level using TEM, HAADF, EDS and XPS; the structural and electronic aspects were systematically studied in using first-principles electronic structure theory within QTAIM framework. The Ag nucleation and formation on α-Ag2WO4 is a result of the order/disorder effects generated in the crystal by the electron-beam irradiation. Both experimental and theoretical results show that this behavior is associated with structural and electronic changes of the [AgO2] and [AgO4] clusters and, to a minor extent, to the [WO6] cluster; these clusters collectively represent the constituent building blocks of α-Ag2WO4.

Elucidating the real-time Ag nanoparticle growth on α-Ag2WO4during electron beam irradiation: experimental evidence and theoretical insights

“…Therefore, these charge injection effects favor the escape of Ag atoms to form new Ag structures, nanowires and clusters as observed in the experiments presented in this article and in previous publications. [49][50][51][52] …”

“…33,37,46,47 This investigation's motivation essentially arises from the discovery of an unwanted real-time in situ nucleation and growth of Ag filaments on a-Ag 2 WO 4 crystals which was driven by an accelerated electron beam from an electronic microscope under high vacuum. 48,49 This is the first example of such studies in the scientific literature and it has become a major topic in current research. It is a novel example…”

An Experimental and Computational Study of β-AgVO3: Optical Properties and Formation of Ag Nanoparticles

“…The reasons for this phenomena have been discussed in recent publications 19,22,24,25 , and the production of Ag NPs on α-Ag 2 WO 4 19, 26-29 , β-Ag 2 MoO 4 30 , and Ag 3 PO 4 23 resulted in interesting applications as sensors, photoluminescent materials, visible-light photocatalysts, and bactericide materials. In this work, we will report, discuss and analyze, for first time, the nucleation process and early evolution of Ag nanoparticles on β-AgVO 3 crystals, provoked by an electron beam, by means of the joint use of an experimental and theoretical studies.…”

Low temperature micro Raman and laser induced upconversion and downconversion spectra of europium doped silver tungstate Ag2−3xEuxWO4 nanorods

“…In fact the Ag ? cation content in the four different coordination sites in a-Ag 2 WO 4 differ dramatically, 15% of these sites are non-centro-symmetric with C 2v symmetry (AgO 2 ), 37% are non-centro-symmetric with T d symmetry (AgO 4 ), 18% are centro-symmetric with O h symmetry (AgO 6 ) and 30% are non-centro-symmetric with D 5h symmetry (AgO 7 ) [18][19][20]. Thus, the electric dipole 5 D 0 ?…”