Novel three-dimensional (3D) hierarchical architectures of Lu2O3:Eu3+ have been successfully prepared through a simple hydrothermal process followed by a subsequent calcination process without using any surfactant, catalyst, or template. According to the X-ray diffraction, thermogravimetric analysis and differential scanning calorimetry, and Fourier transform infrared spectroscopy results, the precursors were determined to have the structure formula of Lu4O(OH)(9)NO3. The morphologies of the precursors could be modulated by altering pH value of the reaction system. On the basis of detailed time-dependent experiments, the growth process of architectures was discussed. The as-formed precursors could transform into Lu2O3:Eu3+ with their original hierarchical structures maintained. The Lu2O3:Eu3+ submicro-architectures exhibit strong red emission corresponding to the D-5(0) -> F-7(2) transition of the Eu3+ ions under ultraviolet (UV) excitation, which have potential applications in novel optoelectronic devices. (C) 2012 Elsevier Inc. All rights reserved.