Hydrophobic perfluoropolymer thin-film encapsulation for enhanced stability of inverted polymer solar cells

We report hydrophobic perfluoropolymer thin-film encapsulation for enhancing the air ambient stability of inverted polymer solar cells (PSCs). Using a perfluoropolymer, poly(perfluorodecylmethacrylate) (PFDMA), as an encapsulation material, an orthogonal process that enables a solution-processing of encapsulation polymers to be coated directly on the inverted PSCs without damaging the underlying organic components is possible. Particularly, with PFDMA encapsulation, the air ambient stability was significantly enhanced, showing only an efficiency reduction of 23.3% after 456 hours of air exposure. The enhanced device stability can be attributed to the hydrophobic property of the PFDMA surface, which suppresses the transmission of air ambient gas molecules into the solar cells. Thus, the PFDMA coating can be beneficial in achieving high-stability organic electronics by using an easy-to-use route.