Thin film phosphors (TFPs) are generally less efficient than powder phosphors because a large fraction of the light generated within the film is lost by the wave-guiding effect. This study examined the effects of the grain size of sol-gel derived nanocrystalline Y2O3:Tb3+ TFPs on the extraction efficiency of emission light and the absorption of UV excitation light caused by Bragg scattering from an over-coated two-dimensional (2D) polystyrene (PS) photonic crystal layer (PCL). The total scattering enhancement of the integrated photoluminescence (PL) efficiency from the 20 mol % Li-doped TFP modified with the 580 nm 2D PS was 9.3 times higher than that of pure flat Y2O3:Tb3+. This was attributed to a combination of increased emission in the anomalous surface scattering enhancement of nanocrystalline films, and both emission and excitation in the Bragg scattering enhancement of 2D PCLs. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3624835] All rights reserved.