Efficient ternary polymer solar cells with a shelf-life stability for longer than 410 days

We have prepared an efficient ternary polymer solar cell incorporating a poly(indacenodithiophene)-based conjugated polymer (PIDTBT), [6,6]-phenyl-C-71-butyric acid methyl ester (PC71BM), and 3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)indanone)-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3-d:2',3-d']-s-indaceno[1,2-b:5,6-b']-dithiophene (ITIC). Grazing-incidence wide-angle X-ray scattering (GIWAXS), atomic force microscopy (AFM), and photoluminescence (PL) spectroscopy revealed that intermolecular interactions between the PC71BM and ITIC units disrupted the formation of large ITIC crystals. The ITIC and PC71BM components formed compatible domains that dispersed well within the PIDTBT matrix, providing optimized ternary blends for efficient carrier transport and led to greater photon-to-electron conversion efficiency. Compared with the pre-optimized PC71BM binary device, the ternary device displayed an improvement in short circuit current density (J(sc)) from 12.0 +/- 0.3 to 14.2 +/- 0.5 mA cm(-2), due primarily to complementary light harvesting in the visible and near infrared regions; as a result, the device performance improved by 20%-from 5.5 +/- 0.2 to 6.6 +/- 0.1% under AM 1.5G (100 mW cm(-2)) irradiation. Furthermore, the ternary cell exhibited outstanding long-term stability, with its performance remaining high (at 6.8%) after storage for 410 days in a glove box (ISOS-D-1 (shelf life-time)).