Blue top-emitting organic light-emitting devices (TOLEDs) with highly saturated color were developed by microcavity effect. The device structure studied was glass/reflective silver/indium-tin oxide (ITO)/organic electroluminescent stack/semi-transparent cathode (calcium/silver). By changing the thicknesses of ITO and organic layers in the microcavity structure device doped with p-bis(p-N,N-di-phenyl-aminostyryl)benzene (DSA-ph), highly saturated color with Commission Internationale de L'Eclairage chromaticity coordinates (CIEx,y) of (0.14, 0.08) was obtained. (C) 2004 Elsevier B.V. All rights reserved.