Study on Langmuir-Schaefer thin films based on amphiphilic organic semiconductor

Abstract

Recently, research on electronic devices using organic semiconductors(OSCs) such as organic field effect transistor (OFET) and organic photovoltaics (OPV) has been conducted. Since the performance of these devices is influenced by the thickness or domain size of the organic semiconductor film, it is important to make a uniform organic semiconductor film. However, it is quite difficult to develop several methods for producing a uniform and controlled layer film over a large area. Langmuir-Schaefer method is a useful and simple technique to fabricate a monolayer of organic materials. The molecules dispersed above water are oriented according to solvent affinity at the interface between water and air. They form a uniform monolayer when the surface area is narrowed. This method does not apply to all molecules, and generally highly oriented layers can be formed in case of amphiphilic molecules. In this master's thesis, we designed a new molecule and presented fabrication method to produce a uniform organic semiconductor thin film. [1] benzothieno [3,2-b] [1] benzothiophene (BTBT) derivatives with hydrophilic groups were designed and synthesized to produce a uniform organic semiconductor thin film by Langmuir-Schaefer technique. In addition, a uniform monolayer was obtained by using the technique, and furthermore, a layer-controlled organic semiconductor thin film could be produced. The thin film was analyzed by methods such as AFM, GIXD, and XRR measurement.