Introduction

Organic Solar Cells (OSCs) are of growing scientific and technological interest as they have the potential to become an attractive alternative for low-cost power generation /1/.

As in OLEDs the intrinsically conductive polymer poly(3,4-ethylenedioxythiophene) / poly(styrenesulfonate), or PEDT/PSS, forms an important component in OSC devices too.

 

In numerous scientific papers the merit of PEDT/PSS employed as an interlayer to planarize ITO and to extract holes from the adjacent light-absorbing layer has been explored /2/. High-conductive PEDT/PSS types are used as transparent electrodes for standard as well as for inverted cell architectures /3/.

Cross-section of a typical OSC layer stack. The transparent electrode may be formed by ITO or alternatively, by high-conductive PEDT/PSS.

 

H.C. Starck provides special grades of PEDT/PSS for OSC applications. The two electronic-grades CLEVIOS™

P VP AI 4083 and CLEVIOS™ P CH 8000 and additionally CLEVIOS™ PH with a higher PEDT-content and higher conductivity are recommended as hole-collection layers and for anode planarization. All three dispersions exhibit a fine particle distribution and will reduce the probability for electrical shorts.

 

For transparent electrodes we recommend CLEVIOS™ PH500, CLEVIOS™ PH510, CLEVIOS™ P HCV4 including high-boiling solvent or ready to use formulation CLEVIOS™ CCP105D or CLEVIOS™ FE. The transparent electrode might also serve as hole-collection layer, as discussed for example in Ref. 3

The application of CLEVIOS™ P in OSCs is closely related to the application in OLEDs. Process steps as “Filtration”, “Pre-Conditioning of the ITO anode” and “Spincoating of electronic grade ”, “Drying of the CLEVIOS™ layer” are identical.

/1/ comprehensive overview on OSCs: MRS Bulletin, Volume 30, January 2005
/2/ Organic Photovoltaics, ed. S.-S. Sun and N. S. Sariciftci, CRC Press, Boca Raton, Florida, USA, 2005
/3/ M. Glatthaar, M. Niggemann, B. Zimmermann, P. Lewer, M. Riede, A. Hirsch, J. Luther; Thin Solid Films, 2005, 491, 298