PTB7:PC₇₁BM bulk heterojunction solar cells exhibiting 9.64% efficiency via adopting moderate polarity solvent vapor annealing treatment

Abstract

The effects of solvent vapor annealing (SVA) with different polar solvents on the performances of polymer solar cell (PSCs) was systematically investigated by applying seven polar solvents, including methanol, acetone, chloroform, o-dichlorobenzene, chlorobenzene, toluene and n-hexane. A 9.64% of power conversion efficiency (PCE) was obtained in the PTB7:PC₇₁BM based PSCs with conventional structure of ITO/PEDOT:PSS/PTB7:PC₇₁BM/LiF/Al by employing the moderate polarity chlorobenzene-SVA method, corresponding to an approximate 21% enhancement in PCE relative to the PSCs without SVA. The enhanced PCEs of PSCs with active layers undergoing chlorobenzene-SVA process are mainly attributed to the combined advantages of the increased absorption intensity, the higher and more balanced carrier mobilities, the upper migration of the PC₇₁BM, and the excellent donor/acceptor phase separation interface in the active layer. Our work not only demonstrates that polar solvent SVA treatment is a much more efficient method of improving the efficiency of PSCs without time-consuming and laborious fabrication procedures, but also provides some feasible reference for the application of different polar solvent SVA treatment in photovoltaic field.

GRAPHICAL ABSTRACT

Keywords:

• Different polar solvents
• power conversion efficiency
• polymer solar cells
• solvent vapor annealing

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Nature Science Foundation of China (Grant No. 61571317), Key Research and Development (International Cooperation) Program of Shanxi (Grant No. 201603D421042), and Platform and Base Special Project of Shanxi (Grant No. 201605D131038), Natural Science Foundation of Shanxi Province (Grant No. 20210302123110).