Screen-printed passive matrix displays and multicolor devices

Due to their outstanding properties organic light-emitting displays based on conjugated polymers are on the verge of commercialization. Two major disadvantages of the current processing technique for polymers, spin-coating of polymer solutions, are the material waste and the difficulties involved in patterning the polymers. Therefore we investigate the screen-printing for the production of polymer displays. Here we present performance data of screen-printed light-emitting diodes of different colors. In the production process of these diodes we printed two layers successively one over the other. Furthermore, we show images of printed multichrome demonstrators and passive matrix displays. Our data indicate that the screen-printing technique has the potential to replace the "classical" spin-coat process. We observe luminance of 10,000 cd/m(2) at 8 V and peak efficiencies exceeding 10 cd/A for green diodes and half lifetime of 170 hours at 80 degreesC and 100 cd/m(2) for red diodes which corresponds to about 7,000 hours at room temperature. These values of printed devices are comparable to those of spin-coated ones.