Smaller cuprous oxides (Cu2O) nanocubes were synthesized by solution-phase method at 160 degrees C, using ethylene glycol reducing Cu(NO3)(2)center dot 3H(2)O with poly(vinylypyrrolidone) (pvp) as capping agent. The Cu2O nanocubes were characterized by field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED) and X-ray powder diffraction (XRD). SEM showed that Most of Cu2O nanocubes were uniform and monodisperse, with the average edge length about 130 nm. The TEM results were consistent with the SEM results. Selected area electron diffraction (SAED) suggested that as-prepared Cu2O nanocubes were single crystalline. The geometric shape and size of Cu2O nanoparticles were greatly affected by the presence of PVP and its molar ratio (in repeating unit) relative to copper nitrate, temperature and the concentration of Cu(NO3)(2)center dot 3H(2)O. The mechanism of Cu2O nanocubes formation was also discussed. (C) 2007 Elsevier Ltd. All rights reserved.