Application of orthogonal photolithography to organic materials and flexible electronic devices

Abstract

Fluorous materials have been receiving great attention as photolithographic materials to actualize photolithographic micro-scale patterned structure for organic electronic devices due to their material advantages such as orthogonality to most organic materials, non-flammability, and low toxicity. Compared with conventional photolithographic materials which generally cause chemical damage to organic layers, fluorous materials can be used to fabricate micro-scale patterned organic device architecture without damage, and they have been consistently developed as photolithographic solvents and imaging resist materials. Recently, orthogonal photolithography using fluorous photolithographic materials have been applied in the field of organic thin-film transistors, logic circuits, non-volatile memory devices, and light-emitting diodes. From among these, organic memory devices have achieved great attention as a candidate for future flexible data storage media with their simple device structure, low cost, printability, flexibility, and low weight. But there still remain several issues to overcome for organic memory devices to be practical electronic products such as micro-scale resolution, reproducibility, uniformity, switching mechanism, and energy efficiency. Here, resistive switching mechanism is particularly important to link electronic properties to material properties for the memory devices. In this thesis, we analyzed development of fluorous photolithographic materials and their application to organic electronic devices such as thin-film transistors, logic circuits, and non-volatile memory devices. Also, organic non-volatile resistive memory devices were researched in terms of morphological properties and energy consumption related to switching mechanism. Lastly, aluminum oxide resistive memory devices on highly flexible paper substrate were successfully fabricated using only physical vapor deposition methods and stably characterized in the flat and bent conditions.