A Printable Organic Cathode Interlayer Enables over 13% Efficiency for 1 cm2 Organic Solar Cells
Qian Kang, Long Ye, Bowei Xu,* Cunbin An, Samuel J. Stuard, Shaoqing Zhang, Huifeng Yao, Harald Ade, and Jianhui Hou*
Joule 2018, 3 (1), 227.
Currently, the lack of printable cathode interlayer (CIL) material has greatly impeded the pace toward practical production of organic solar cells (OSCs). Herein, we report a naphthalene diimide (NDI)-based small molecular compound (N,N-dimethylamino)propyl naphthalene diimide (NDI-N) as printable CIL for OSCs. NDI-N exhibits a unique advantage that combines the merits of high crystallinity and good film-forming property in one material, endowing the semiconductor with excellent electron transport property and good processability. By using the NDI-N as CIL, a high power conversion efficiency (PCE) of 13.9% was achieved in a PBDB-T-2F:IT-4F-based OSC device. More importantly, a large-area OSC device of 1 cm2 was fabricated by using the blade-coated NDI-N CIL and an outstanding PCE of 13.2% was achieved, which represents the highest efficiency of large-area OSCs. The results in this work may pave the way to the low-cost and mass production of OSCs.