A simple technique of maskless dye diffusion into polymer films on prepatterned electrodes is developed and three-color polymer light-emitting devices were successfully fabricated on a glass plate. In this method, prepatterned electrodes beneath precoated receiver film are utilized as heaters for activating dye molecules. Upon doping with three types of dye, 1,1,4,4-tetraphenyl-1,3-butadiene, coumarin 6 and Nile red into poly(N-vinylcarbazole) by the present diffusion method, blue, green and red emission were obtained. It is found that the onset voltage of emission does not depend on the type of dye. The maskless dye diffusion technique can be applicable to a variety of devices such as photovoltaic devices. (c) 2005 Elsevier B.V. All rights reserved.