In this Letter, we present and analyze the operation lifetime behaviors of organic light-emitting devices by changing thicknesses of the hole-transport layer (HTL), the emitting layer (EML) and the electron transport layer (ETL). It is found that devices with higher power efficiency exhibit longer lifetimes. Given the same power efficiency, devices with a thicker HTL (or a thinner EML and ETL) have longer lifetimes. We also observe that, among different samples, the fixed charge density increasing rate near the HTL/EML interface is linearly correlated to the non-radiative center formation rate. (C) 2004 Elsevier B.V. All rights reserved.