The monoclinic Gd2O3 nanoplates phosphor doped with Eu3+ in the size range similar to 200 to 500 nm and the thickness of several tens of nanometers has been synthesized using the pulp precursor. The particle size and morphology were observed by scanning electron microscopy and transmission electron microscopy. The photoluminescence spectrum is described by the well-known D-5(0)-> F-7(J) transition (J=0, 1, 2, etc.) of Eu3+ ions with the strongest emission for J=2 at 615 and 624 nm. The monoclinic Gd2O3:Eu nanoplates show a quantum efficiency of 83%, a superior color chromaticity (x=0.662, y=0.338) and a dramatic shorter of decay time compared to the cubic-type bulk Gd2O3:Eu phosphor. (c) 2007 The Electrochemical Society.