Light emitting devices were fabricated in planar (surface cell) configurations with low operating voltage. Polymer blends composed of a red or green color luminescent polymer and solid state electrolyte were used as the active materials. Under external bias, electrochemical doping occurs in the vicinity of the contact, and a dynamicp-njunction forms between the electrodes. Light emission is observed in the junction area at bias voltages greater than 2 V, reaching102cd/m2at voltage well below 5 V. The planar configuration allows display devices to be hybridized with integrated circuits on a silicon wafer. On transparent substrates, such as glass or plastic films, light emission can be viewed from both sides of the device. Emissive displays in the planar surface cell configuration can be fabricated using roll-to-roll processing at room temperature without need for vacuum equipment. ©1997 American Institute of Physics.