First Step into Space: Performance and Morphological Evolution of P3HT:PCBM Bulk Heterojunction Solar Cells under AM0 Illumination

P3HT (poly(3-hexylthiophene-2,5-diyl)):PC61BM ([6,6]-phenyl-C61 butyric acid methyl ester) bulk heterojunction solar cells are fabricated and characterized as a function of solar intensity, temperature, and aging at vacuum conditions under illumination with AM0 illumination for testing potential use in space applications. The evolution of the inner film morphology is probed with grazing incidence X-ray scattering techniques and correlated with the evolution of the efficiency during aging. Grazing incidence wide-angle X-ray scattering shows almost no change of the crystalline structure of the P3HT:PCBM films due to aging. In contrast, the morphological evolution on the mesoscale extracted from grazing incidence small-angle X-ray scattering can explain the observed decay of the overall efficiency. The behavior at high solar intensities as well as elevated temperatures suggests that organic solar cells have high potential for space applications in the future.