Fully doctor-bladed efficient organic solar cells processed under ambient condition

Abstract

The low-cost and high-throughout printing techniques are potentially used to process large-area organic solar cells (OSCs). However, high-performance OSCs fabricated via fully printing process have lots of challenges. Herein, OSCs are fabricated via fully doctor blading using subsequently printed electron transport layer (ETL) zinc oxide (ZnO), printed bulk heterojunction (BHJ) active layer composed of poly[(2,6-(4,8-bis(5-(2-ethylhexy)thiophen-2-yl)-benzo[1,2-b:4,5-b’]dithiophene))-alt-(5,5-(1′,3′-di-2-thienyl-5′,7′-bis(2-ethylhexyl)benzo[1′,2′-c:4′5′-c’]dithiophene-4,8-dione))] (PBDB-T) and 3,9-bis(2-methylene-(3-(1,1-dicyano-methylene)-5-methylindanone)-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3 -d:2′,3’ -d’]-s- indaceno[1,2-b:5,6-b’]-dithiophene (IT-M), and printed hole transport layer (HTL) molybdenum oxide (MoO3). Through the optimization of inks and printing parameters, as well as humidity control, OSCs fabricated via printed ETL ZnO in ambient condition and spin-coated BHJ PBDB-T:IT-M in glovebox produce a power conversion efficiency (PCE) of 10.73%, which is similar to fully spin-coated device. While OSCs fabricated via printed ETL ZnO and BHJ PBDB-T:IT-M in ambient condition can produce a PCE of 10.15%. Furthermore, the PCE up to 9.34% can be achieved for fully printed OSCs with doctor-bladed ETL ZnO, BHJ PBDB-T:IT-M and HTL MoO3 in ambient condition. These results suggest that high-performance OSCs can be fabricated using printing techniques in ambient condition instead of spin-coating and inert atmosphere, exhibiting great potential to accelerate the commercialization of OSCs.