Screen printed PEDOT:PSS films as transparent electrode and its application in organic solar cells on opaque substrates

In this manuscript, we demonstrate screen printing, a low cost printing method, of PEDPOT:PSS as top transparent electrode which was integrated with organic solar cell devices fabricated on opaque steel substrates with device structure being Steel/Insulator/Al/ZnO/P3HT:PC61BM/PEDOT:PSS. To print PEDOT:PSS on the surface of hydrophobic active layer of P3HT:PC61BM, PEDOT:PSS is modified with isopropyl alcohol (IPA) and Fluorosurfactant Zonyl FS-300. Further, two-step annealing of screen printed PEDOT:PSS films, 50 °C for 5 min and then at 130 °C for 3 min, is found to be crucial in rendering low surface roughness. Adoption of these strategies together yielded PEDOT:PSS films of thickness in the range of 500–700 nm consistently with a roughness of ca. 55 nm. These PEDOT:PSS films were coupled with silver (Ag) grids in organic solar cell devices which yielded power conversion efficiency of ca. 0.7%.