Opto-electronic devices such as solar cells and light-emitting diodes based on conjugated polymers have received attention over the past decades. The charge transporting and injecting/collecting properties are crucial factors for improving the performances of the devices. Among them, the charge injecting/ collecting properties are related to the interfacial properties between the semiconducting layer and the cathode or the anode. Water or alcohol soluble conjugated polymer electrolytes, alcohol-soluble neutral conjugated polymers have been mainly applied to the solution processable cathode interface layer of opto-electronic devices. Solution processable n-type metal oxides have been used as a solution processable cathode interface layer to improve the electron injecting/collecting properties of the opto-electronic devices. In this presentation, new types of cathode buffer layer materials such as polyviologen, poly(sodium 4-styrenesulfonate), and polyvinyl alcohol for the applications in organic solar cells will be introduced. Also, we will present the effect of arrangement of side chains of conjugated polymer electrolytes on the photovoltaic properties.
Key Words: Solar Cell, polymer electrolyte, buffer layer