1 Department of Energy Conversion and Storage, Technical University of Denmark2 Functional organic materials, Department of Energy Conversion and Storage, Technical University of Denmark3 Chinese Academy of Sciences4 Risø National Laboratory for Sustainable Energy, Technical University of Denmark5 Zhejiang University6 Peking University7 Zhejiang University8 Peking University
All-polymer and polymer/fullerene inverted solar cells were fabricated by spin-coating and roll-coating processes. The spin-coated small-area (0.04 cm(2)) devices were fabricated on indium tin oxide (ITO) coated glass substrates in nitrogen. The roll-coated large-area (1.0 cm(2)) devices were prepared on ITO-free flexible substrates under ambient conditions. The use of a solvent additive, 1,8-diiodooctane (DIO), facilitated phase separation and enhanced power conversion efficiencies (PCEs). The PCE of polymer/fullerene solar cells increased from 4.58% to 8.12% with 2.5% (v/v) DIO when using the spin-coating process, and increased from 1.37% to 2.09% with 5% (v/v) DIO in the roll-coating process. The PCE of all-polymer solar cells increased from 1.44% to 3.51% with 4% (v/v) DIO when employing the spin-coating process. For the roll-coated large area devices the PCE increased from 0.15% to 0.73% with 9% (v/v) DIO. The optimal amounts of DIO, when using the roll-coating process for the two different active layers (5% and 9% respectively) are significantly higher than those for the spin-coating process (2.5% and 4%, respectively), which is ascribed to a fundamentally different drying mechanism.
Journal of Materials Chemistry a, 2014, Vol 2, Issue 45, p. 19542-19549
CHEMISTRY,; ENERGY; MATERIALS; BULK-HETEROJUNCTION; HIGH-PERFORMANCE; EFFICIENCY ENHANCEMENT; PHOTOVOLTAIC POLYMERS; SOLVENT ADDITIVES; SELF-ORGANIZATION; DEVICE EFFICIENCY; SMALL MOLECULES; ACTIVE LAYERS; SIDE-CHAINS