PEDOT:PSS layers as replacements for the transparent conductive coatings of organic solar cells

There are efforts to replace the classical transparent conducting coating, Indium Tin Oxide (ITO), (or other TCOs) by a new class of materials which are easier to handle and cheaper in mass production. Transparent conductive coatings are produced which consist of polymers or carbon nanotubes (CNT). In this investigation poly(3,4-ethylenedioxythiophene) :poly (styrene sulfonate) (PEDOT:PSS) and not functionalized single wall carbon nanotubes (SWNT) are used to produce transparent conducting coatings to replace the ITO layer. In a first step dimethyl sulfoxide (DMSO) and ethylene glycol (EG) are added in order to render the film electrically conductive. With these additions an increase in the electrical conductivity from 0.035 S/cm to 148 S/cm is obtained. In a second step an additional layer of single wall carbon nanotubes (SWNT) is inserted underneath the PEDOT:PSS. For these additions a significant decrease of the parallel resistance is observed.