Efficient organic solar cells with the active layer fabricated from glovebox to ambient condition

Abstract

Organic solar cells (OSCs) have been attracting considerable interest due to their unique advantages of low cost, light weight, and especially mechanical flexibility. The low-cost and high-throughput techniques matching with the large-scale and roll-to-roll (R2R) process for fabricating efficient OSCs in the ambient condition would greatly accelerate the potential commercialization of OSCs. Herein, we demonstrate that the fabrication processes of OSCs using the bulk heterojunction (BHJ) 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-dicyanomethylene)-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) are transferred from a glovebox to the ambient condition, where the deposition of doctor blading instead of conventional spin coating is investigated. The morphology, microphase separation, and crystallinity of BHJ PBDB-T:IT-M are dramatically influenced by the fabrication processes. The OSCs with a structure of ITO/ZnO/PBDB-T:IT-M/MoO3/Ag fabricated via doctor-blading in the ambient condition show a power conversion efficiency (PCE) of 9.0% as compared to conventional spin-coated OSCs in a glovebox with a PCE of 11.91% and in the ambient condition with a PCE of 9.91%. These results suggest that efficient OSCs could be processed in the ambient condition by large-scale and low-cost doctor-blading, which can be compatible with the R2R manufacturing process.