High-efficiency polymer solar cells by blade coating in chlorine-free solvents

•The PBDTTT-C-T has the good solubility in the chlorine-free solvents.•A high-performance OPV can be fabricated using blade coating technique.•The highest efficiency achievable by blade coating was 6.11%.•The highest efficiency achievable by spin coating was 6.42%.•The toxic chlorine solvents in polymer solar cells can be avoided.

High-performance polymer cells are typically fabricated by employing toxic solvents such as dichlorobenzene and chlorobenzene. In this study, blade coating with the chlorine-free solvents toluene and xylene is applied to polymer solar cells that contained the low band-gap polymer PBDTTT-C-T blended with [6,6]-phenyl-C71-butyric acid methyl ester ([70]PCBM). The highest efficiencies of the cells fabricated in toluene and xylene solutions were 6.09% and 6.11%, respectively. Atomic force microscopy images show that the films formed by blade coating using toluene and xylene were extremely smooth, with roughness of only 1 nm. This blade coating has a rapid-drying in a few seconds without the long-running thermal or solvent annealing. The possibility of high-volume environmentally-friendly fabrication of efficient polymer solar cells with minimal material waste is thus demonstrated using a combination of chlorine-free solvents and blade coating.

Graphical abstractHigh-performance polymer solar cells based on PBDTTT-C-T were successfully fabricated using blade coating in the chlorine-free solvents toluene and xylene solution. Remarkable efficiencies of 6.11% has been realized which demonstrate that organic solar cells can be fabricated with high throughput in an environmentally friendly manner by rapid-drying blade-coating technique.Figure optionsDownload full-size imageDownload as PowerPoint slide