(An) empirical study on the spontaneous spreading phenomenon for the formation of polymer thin film and its application to photovoltaic devices

Abstract

This dissertation is a study on the principle of spontaneous diffusion phenomenon of polymer - organic solvent mixed solution on fluid substrate and its application to photovoltaic devices. Surface properties of water and polymer-organic solvents are important factors for precisely controlling the spontaneous spreading phenomenon. It is possible to stably form thin polymer layer on water and to apply the film to efficient electronic devices by controlling these surface properties well. In addition nanomorphology including the crystallization, chain alignment, and phase separation in a BHJ film can be efficiently managed in a very short time by controlling spreading flow of organic active layer solution on the water substrate. This nanomorphol-ogy of a photoactive layer exhibits polymer solar cells with a high power conversion efficien-cy of 8.44%. Finally, we confirmed the potential as a technology by using a roll-to-roll pro-cess capable of forming a 1-m-thick polymer film and transferring.