Large-Area Wet Micro-Printing (LAMP)for Organic Device Patterning
- PDF / 2,032,251 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 59 Downloads / 233 Views
I6.27.1
Large-Area Wet Micro-Printing (LAMP) for Organic Device Patterning Hongzheng Jin1,2 and James C. Sturm1,2 1 Department of Electrical Engineering, Princeton University, Princeton, NJ 08544, USA 2 Princeton Institute for the Science and Technology of Materials (PRISM), Princeton University, Princeton, NJ 08544, USA ABSTRACT An important challenge for Organic Light-Emitting Diodes (OLEDs) manufacturing is the patterning method of the organic materials used for different colors. In this talk, a Large-Area wet Micro-Printing (LAMP) technique is proposed and demonstrated for organic device patterning. A printing plate is first prepared by surface engineering so that a designed surface energy pattern is achieved. The printing plate is then coated with “ink,” brought into contact with the device substrate, and the “ink” is transferred. With this approach, the red (R), green (G) and blue (B) sub-pixel arrays needed in a full-color display can be printed in three successive steps, one step for each color. Both single-color pixel arrays and R, G, B sub-pixel arrays have been patterned as a demonstration of the feasibility of this method. The technique has the potential advantages of low-cost and high-throughput and it avoids some of the practical problems associated with the design and operation of an ink-jet apparatus. INTRODUCTION In the fabrication of monochrome OLEDs, active materials are usually deposited by thermal evaporation for small molecules or by spin-coating for polymers. A full-color OLED, however, requires the patterning of different organic materials used for R, G, B sub-pixels. Patterning of small molecules can be achieved by thermal evaporation and shadow mask, while ink-jet printing [1,2] has been widely developed for polymers. Nevertheless, there are several shortcomings to ink-jet printing, such as nozzle clogging, repeatability of the direction of droplet travel, and throughput [2]. The approach demonstrated in this work is to print organic device layers from a wet solution not drop by drop, as in ink-jet printing, but rather over a large area at once using a patterned printing plate. We refer to the method as Large-Area wet Micro-Printing (LAMP). This method uses surface engineering techniques to pattern the surface energy of a printing plate and then uses the printing plate to locally deposit organic materials. Patterning of different color pixels for full-color OLED can be achieved by three successive printing steps. Both single-color pixel arrays and R, G, B sub-pixel arrays are demonstrated. Monochrome OLED devices were tested for their electrical and electroluminescent properties. The printed devices show efficiencies somewhat lower than those by spin-coating. The results suggest that LAMP is a promising patterning technique for low-cost full-color OLED displays. EXPERIMENTAL DETAILS The LAMP technique is illustrated schematically in Figure 1. A printing plate is first prepared by surface energy patterning (discussed below) so that a designed wettability pattern is
I6.27.2
Printing Plate
Data Loading...
