In this thesis, micro-patterns of printed electronics are studied as an alternative to vacuum deposition technology, which is difficult to apply in a large area. Currently, this technology is considered more attractive, especially in the field of displays, where substrates with a size of the eighth generation or more are used based on the glass substrate. In addition, the printing technology involves printing-drying, so the manufacturing process is simple, and there is an advantage in terms of the efficiency of materials and the manufacturing. In this dissertation, a fine pattern that can be manufactured by a printed electronic process that can be applied in the field of displays is discussed. It presents the research on flexible transparent electrodes with improved conductivity and LED devices capable of realizing high-resolution pixels.
Chapter 2, describes an auxiliary electrode with Ag ink that was printed on an ITO film using the electrohydrodynamic(EHD) continuous printing method. The printed electrode could minimize the decrease in transmittance while improving the performance of the flexible electrode having low conductivity. The possibility of a printed auxiliary electrode was confirmed by manufacturing an electrochromic device with flexible properties by applying it to the electrochromic device.
Chapter 3, describes the development of an ink by using, the material used as the light-emitting layer in an organic light-emitting device. A light-emitting layer with high resolution was manufactured using a photothermal transfer process. The inked material was printed on a pre-fabricated pattern using an inkjet process, and the printed pattern was transferred using a photothermal transfer process. The pre-fabricated pattern was designed to have a micropattern of a size corresponding to 500, 700, and 1000 pixels per inch (PPI). In addition, a polymer additive type ink was developed to ensure stable transfer of the photothermal transfer layer. The polymer additive improved the transfer efficiency by reducing the crystallization of the inked light-emitting layer material.
Chapter 4, describes the fabrication of a pixel-type QLED device with a 200 PPI level using quantum dots. Quantum dot material was mixed with ink suitable for inkjet and surface treated using the Trichloro(1H,1H,2H,2H-perfluorootyl) silane (FDTS) self-assembly monolayer (SAM) stamp process for stable printing and control of color mixing. In addition, the ZnO nanoparticle ink, a lower layer, was improved using the inkjet process for fabricating of an inverted structure QLED device. In particular, the quantum dot ink was designed using a co-solvent method based on the number of Ohnesorge. The inkjet-printed quantum dot layer obtained a low thin film flatness ratio and low surface roughness. The possibility of a printed quantum dot device was confirmed by fabricating an inverted QLED.