Tetrabranched Photo-Crosslinker Enables Micrometer-Scale Patterning of Light-Emitting Super Yellow for High-Resolution OLEDs
Wooik Jang, Myeongjae Lee, Hyukmin Kweon, Hye Won Park, Jeehye Yang, Seunghan Kim, Hyunwoo Jo, Chaeyoung Lee, Jeong Ho Cho, Kyungwon Kwak, Do Hwan Kim, BongSoo Kim, Moon Sung Kang
Abstract
Development of a simple and effective patterning method applicable to solution-processable organic luminophores over a large area is critical for the cost-effective production of organic light-emitting-diode (OLED) displays. Here, we demonstrate high-resolution patterning of light-emitting polymer active layers using a highly efficient photo-crosslinker (4Bx). The photo-crosslinker is structured in a tetrabranched geometry, wherein a photo-crosslinkable azide moiety is present at each of the four corners of the molecule, and each of these moieties can form a chemical bond with light-emitting polymer semiconductors under UV irradiation. Due to the high crosslinking efficiency of 4Bx, the use of an unprecedentedly small amount of 4Bx (0.1 wt %) allows fully crosslinking light-emitting Super Yellow polymers without degrading their photoluminescence and electroluminescence characteristics. Furthermore, precisely defined photo-crosslinked patterns of Super Yellow with feature sizes of 5 mu m are formed by using p-xylene as the developing solvent that was carefully selected according to a Hansen solubility parameter analysis.