Brominated Perylene Diimides as Cathode Interface Materials for High Efficiency Organic Solar Cells

The cathode interface materials (CIMs) are crucial for organic solar cells (OSCs). Herein, excellent CIMs PDINN-Br and PDINN-2Br are reported, by bromination of PDINN. Both of them have strong work function (WF) tunability, self-doping properties, and excellent film-forming properties. They show higher electron mobility (over 2 x 10-4 cm2 V-1 s-1) and conductivity (approximate to 5 x 10-5 S cm-1) than PDINN. Grazing-incidence wide-angle X-ray scattering measurements (GIWAXS) illustrate that PDINN-2Br has more ordered arrangement than PDINN and PDINN-Br. PDINN, PDINN-Br, and PDINN-2Br in PM6:Y6-based OSCs lead to 15.96%, 16.71%, and 17.03% power conversion efficiency (PCE), respectively. The PDINN-2Br has well performance as well in the PM6:PYIT and D18:L8BO OSCs, PCEs of 18.14% and 18.98% are obtained, respectively, which are higher than PDINN (16.97% and 18.01%). The cathode interface materials (CIMs) are crucial for organic solar cells (OSCs). Herein, Excellent CIMs PDINN-Br and PDINN-2Br are reported, by bromination of PDINN. Both of them have strong work function (WF) tunability, self-doping properties, and excellent film-forming properties. In particular, PDINN-2Br has shown good performance in different active layer devices. image