An Introduction to Poly(3,4-thiophene) ethylenedioxy-Polystyrene Sulfonate as a Hole Transporting Layer in Polymer Solar Cells

Polymer solar cells (PSCs) as one of the new types of solar cells have attracted a lot of attention due to their some advantages such as flexibility, light weight, low-cost large-scale manufacturing and solution processability. This category of PSCs is composed of three main layers including anode, active layer and cathode. The layers entitled "hole transporting layer" (HTL) and "electron transporting layer" (ETL) are generally designed in the main structure of a PSC. These layers improve the solar cell performance in conversion of solar energy to electricity. HTL as a layer can block electron movement to anode and only allows holes to move. Various compounds are introduced as "hole transporting" materials. Today, the most successful candidate material as "hole transporting" material for polymer solar cells is poly(3,4-ethylene dioxythiophene) polystyrene sulfonate or PEDOT:PSS which is composed of conductive PEDOT and PSS insulator. In this paper, the synthesis methods of PEDOT:PSS and its properties and components are introduced and its electrical property is optimized in order to enhance the performance of PSC, while the "hole transportation mechanism" has been considered in the polymer solar cell structure.