Surface-modified CuO layer in size-stabilized single-phase Cu2O nanoparticles

Abstract

Activated reactive evaporation has been used to grow copper oxide nanoparticles in the size range of 8–100 nm. X-ray diffraction spectra clearly show the presence of a single Cu2O phase. Detailed x-ray photoelectron spectroscopy studies show an increase in the ionicity of the Cu2O system with decreasing particle size. Depth profiling and finger printing of x-ray photoelectron spectra reveal that the Cu2O nanoparticles are capped with a CuO surface layer of thickness ≈1.6 nm. This study strongly suggests that the stabilization of the cubic Cu2O nanophase is enhanced by the formation of a CuO surface layer.

Temperature dependence of Cu 2 O orientations in the oxidation of Cu (111)/ZnO (0001) by oxygen plasma

“…It shows clearly that at the surface, the Cu 2p 3/2 signal can be simulated as a summation of two peaks located at 932.2 eV and 933.5 eV respectively by using the Gaussian fit (not shown here), while that of the as-sputtered surface (the top 5 nm layer was sputtered off) only consists of the former component. [27] Due to the existence of Cu vacancy, the intrinsic Cu 2 O is conclusively p-type conductive, which has been supported by many theoretical and experimental research results. [28,29] However, some groups claimed that they obtained n-type Cu 2 O (especially those grown by using the electrodeposition method), and some explanations were put forward.…”

Size dependence of nanostructures: Impact of bond order deficiency

“…The grain size and the electric conductivity of the SrTiO 3 nanosolid increase with the annealing temperature [54]. Size-enhanced gas sensitivity of SnO 2 nanoparticles [52] and size-enhanced ionicity of Cu 2 O nanoparticles have also been observed [55]. Introducing ferroelectric materials of different sizes into a photonic crystal could modulate its refractive index and hence the photonic band gap, E G , which is sensitive not only to the external stimuli such as temperature or electric field, but also to the particle sizes.…”

Effect of Ultrasonic‐assisted Preparation Methods on Structure, Morphology and Optical Properties of Nanosized Cupric Oxide

“…Chen et al 18 have reported the synthesis of CuO shuttle-like nanocrystals via the hydrothermal decomposition route using the pre-obtained Cu(OH) 2 as the copper source in the absence of any surfactants. Synthesis of CuO nanorods and nanoribbons at the moderate temperature (77-82 ºC) in water-ethanol solutions were also reported by Chang et al 19 Balamurugan et al 20 reported the synthesis of nanosized CuO by the electrodeposition of Cu(II) ions followed by the gas-solid reaction. Kim and co-workers synthesized porous CuO nanowires by deposition of Cu on the porous single-walled carbon nanotube substrate followed by a thermal oxidation process.…”

“…Despite considerable efforts devoted to the preparation of the nanosized CuO, [15][16][17][18][19][20][21][22][23][24][25] there is a lack of information about ultrasonic-assisted (US) preparation methods especially US thermal decomposition and US liquid hydrolysis methods.…”