Quantum size effects in CuO nanoparticles

Size dependence of nanostructures: Impact of bond order deficiency

“…which agrees with the trends measured using XPS from CuO surface [535]. The observed peak intensity increases and the peak-base width (rather than the full width at half maximum that describes the distribution of the occupied DOS in the core band) decreases with reducing particle size.…”

“…The mechanism of surface interlayer relaxation [540] induced positive shift and the specification of the capping and surface layers in CdS and ZnS nanosolids are highly favored. Atomic CN imperfection also enhances the ionicity of the constituent atoms such as oxygen and metals [535]. The artifacts added to the XPS spectrum due to photovoltaic effects in experiments and the excited final states could be removed by proper calibration of the data.…”

“…The corresponding positive shift was explained as the enhanced interlayer charge density and the enhanced resonant diffraction of the incident light irradiation due to the surface bond contraction [495,540]. (ii) The size-induced Cu-2p core-level shift of a CuO nanosolid was ascribed as the sizeenhanced ionicity of copper and oxygen [535]. This suggestion means that an oxygen atom bonds more strongly to the Cu atoms in a nanosolid than does the oxygen atom to the Cu atoms inside the bulk.…”

“…Assuming m ¼ 4 for OeCu, we can use the measured data [535] to estimate the E 2p (1) and the DE 2p (N) of bulk Cu and bulk CuO, as given in Table 12. The estimated values seem to be too large to be reasonably compared with those obtained from Cu/HOPG or Cu/CYCL.…”

Copper Oxide Nanostructures; Syntheses and Characterization

“…However, the reports on the preparation and characterization of nanocrystalline CuO are relatively few to some other transition metal oxides such as zinc oxide, titanium dioxide, tin dioxide and iron oxide. Some methods for the preparation of nanocrystalline CuO have been reported recently such as the sonochemical method [0], sol-gel technique [7], one-step solid state reaction method at room temperature [8], electrochemical method [9], thermal decomposition of precursors [46] and coimplantation of metal and oxygen ions [44] etc. Laser ablation in liquid media is a 'top down' approach for the synthesis of nanomaterials having desired shape, size and chemical composition and surfaces free from chemical contamination, which are essential for further functionalization of nanomaterials for biological and sensing applications.…”