Size-modified d bands and associated interband absorption of Ag nanoparticles

Abstract

The present study shows important evidence revealing an intimate relationship between the size-induced modifications of electronic structure and optical properties of Ag nanoparticles. Optical absorption spectra of Ag nanoparticles consisting of two predominant peaks corresponding to characteristic plasmon absorption due to the collective oscillations of conduction-band electrons and an interband absorption due to the transition of electrons from the completely occupied d bands to an empty state above the Fermi level in the conduction band have been observed to depend on the nanoparticle size. On the reduction of nanoparticle size, the interband absorption peak becomes sharp and intense and its peak position shifts towards the lower energy side, which is found to be associated with the size-induced changes in the d bands observed by x-ray photoelectron spectroscopy.

Elucidating the 4f Binding Energy of an Isolated Pt Atom and Its Bulk Shift from the Measured Surface- and Size-Induced Pt 4f Core Level Shift

“…An increase in core-level BE with decreasing particle size has been observed frequently in numerous species such as Au, Ag, Ni, Cu, Pd, Si, C, etc., and their compounds as well. [3][4][5][6][7][8][9] For instances, calculations 10 suggested that the 2p binding energies of Cu 18 and Ni 18 atomic clusters undergo positive shifts from their bulk values (taking as zero) to 0.7-0.8 eV when the average strain of the clusters are increased from zero to 6%. A combination of scanning tunneling microscopy/spectroscopy measurements and density functional theory as well as molecular dynamics calculations revealed that the mean lattice constant of Co nanoislands contracts by 6% from the bulk value of 0.251 to 0.236 nm from the center to the edge of the nanoislands deposited on copper substrates; 11 an apparent energy shift of ∼0.2 eV of the occupied valence states has been detected when the island size is reduced from 22.5 to 4.8 nm.…”

The size controlled synthesis of Cu2S/P25 hetero junction solar-energy-materials and their applications in photocatalytic degradation of dyes

“…38,39 Balamurugan B. has reported the sizedependent changes in Cu 2 O nanoparticles, result in conductivity type inversion on reduction of nanoparticle size. [40][41][42] So it is necessarily to know how and what is the extent the quantum connement of Cu 2 S effect on the visible light catalytic performance. In the present work, a series of different Cu 2 S size were Fig.…”

Structural investigation of photonic materials at the nanolevel using XPS

“…The ability of XPS to provide information concerning the formation of nanostructures embedded in an amorphous glassy matrix is confirmed also considering the sodalime glasses. There is a wide literature concerning the effects of quantum confinement on the XP-core lines ( [9][10][11] and references therein). Here we present the results of a complex analysis which accounts both for chemical and structural effects.…”