Toward Long‐Term Stable and Efficient Large‐Area Organic Solar Cells

Abstract

Abstract Here, we report that long‐term stable and efficient organic solar cells (OSCs) can be obtained through the following strategies: i) combination of rapid‐drying blade‐coating deposition with an appropriate thermal annealing treatment to obtain an optimized morphology of the active layer; ii) insertion of interfacial layers to optimize the interfacial properties. The resulting devices based on poly[4,8‐bis(5‐(2‐ethylhexyl)thiophen‐2‐yl)benzo[1,2‐b;4,5‐b′]dithiophene‐2,6‐diyl‐ alt ‐(4‐(2‐ethylhexyl)‐3‐fluorothieno[3,4‐b]thiophene‐2‐carboxylate‐2,6‐diyl)] (PBDTTT‐EFT):[6,6]‐phenyl C 71 butyric acid methyl ester (PC 71 BM) blend as the active layer exhibits a power conversion efficiency (PCE) up to 9.57 %, which represents the highest efficiency ever reported for blade‐coated OSCs. Importantly, the conventional structure devices based on poly(3‐hexylthiophene) (P3HT):phenyl‐C 61 ‐butyric acid methyl ester (PCBM) blend can retain approximately 65 % of their initial PCE for almost 2 years under operating conditions, which is the best result ever reported for long‐term stable OSCs under operational conditions. More encouragingly, long‐term stable large‐area OSCs (active area=216 cm 2 ) based on P3HT:PCBM blend are also demonstrated. Our findings represent an important step toward the development of large‐area OSCs with high performance and long‐term stability.