Cu doped ZnO nanoparticle sheets were synthesized via a proposed solution route with mixed Zn(NO3)(2) and Cu(NO3)(2) precursors at a low temperature of 95 degrees C. Scanning electron microscopy, transmission electron microscopy, and X-ray energy dispersive spectrometry results demonstrate that the nanostructues synthesized by solutions with higher Cu(NO3)(2) concentration are nanoparticle sheets comprised of uniform Cu doped ZnO nanoparticles with diameters around 20 nm. Room-temperature photoluminescence spectra of the nanoparticle sheets show tunable near band emissions centered at 390-405 nm and strong yellow emissions at 585-600 nm. Absorbance spectra show gradual redshift in the UV range with the increase of Cu concentrations in the ZnO nanomaterials. The study provides a simple and efficient route to prepare Cu doped ZnO nanomaterials at low temperature. The as-synthesized products with both violet and yellow emissions are promising for white light-emitting diode applications. (C) 2010 Elsevier B.V. All rights reserved.