| An important challenge for organic light-emitting diodes (OLED) manufacturing is the patterning method of the organic materials used for different colors. In this thesis, we have developed several novel patterning techniques for full-color OLED patterning.;The first method is referred to as the Large-Area Wet Micro-Printing (LAMP) method. The surface engineering techniques used to pattern the surface energy of a printing plate will be introduced. The printing setup, including parallel and registration alignment, will be discussed. Both single-color and RGB sub-pixel arrays are demonstrated. The LAMP method is a parallel process, which may have a low-cost and high-throughput potential.;The thickness of the wet-printed films is usually non-uniform. Two main approaches, a co-solvent approach and a surfactant approach, will be shown to effectively flatten the printed film. In addition, the effect of surfactant on the device performance is also studied. The use of FC-4432 surfactant is able to flatten the PVK profile without sacrificing the device performance.;The second method, transfer printing, is a dry printing method. The principle and mechanism of the transfer printing method will be discussed. RGB subpixel arrays will be demonstrated, with a color display resolution of 530 ppi. OLEDs with polymer layers printed under low temperature (50°C) show performance comparable to spin-coated control devices. The transfer printing method is demonstrated with very uniform film thickness with sharp edges and a very high resolution. It has a low-cost and high-throughput potential since it is a parallel process.;An alternative transfer printing method is also introduced, with the polymer layer deposited directly onto the stamp surface by spin coating. Two different approaches, a hard-hard approach and a hard-soft approach, are proposed. The hard-soft approach is shown with ability to accommodate non-uniform films. RGB subpixel arrays are demonstrated for both of the two approaches. |
