Roth, Bérenger1; Benatto, Gisele Alves dos Reis3; Corazza, Michael1; Søndergaard, Roar R.1; Gevorgyan, Suren1; Jørgensen, Mikkel1; Krebs, Frederik C1
1 Department of Energy Conversion and Storage, Technical University of Denmark2 Functional organic materials, Department of Energy Conversion and Storage, Technical University of Denmark3 Department of Photonics Engineering, Technical University of Denmark
The impact of additives mixed with poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) on the stability of organic photovoltaic modules is investigated for fully ambient roll-to-roll (R2R) processed indium tin oxide free modules. Four different PEDOT:PSS inks from two different suppliers are used. The modules are manufactured directly on barrier foil without a UV filter to accelerate degradation and enable completion of the study in a reasonable time span. The modules are subjected to stability testing following well-established protocols developed by the international summit on organic photovoltaic stability (ISOS). For the harsh indoor test (ISOS-L-3) only a slight difference in stability is observed between the different modules. During both ISOS-L-3 and ISOS-D-3 one new failure mode is observed as a result of tiny air inclusions in the barrier foil and a R2R method is developed to detect and quantify these. During outdoor operation (ISOS-O-1) the use of ethylene glycol (EG) as an additive is found to drastically increase the operational stability of the modules as compared to dimethylsulfoxide (DMSO) and a new failure mode specific to modules with DMSO as the additive is identified. The data are extended in an ongoing experiment where DMSO is used as additive for long-term outdoor testing in a solar park.