High-performance polymeric photovoltaic cells with a gold chloride-treated polyacrylonitrile hole extraction interlayer

We introduce a high efficiency polymeric photovoltaic cell (PPV) to be obtained by polyacrylonitrile (PAN) hole extraction layer (HEL) modification with gold chloride (AuCl₃). The role of PAN HELs with AuCl₃ and their effects on solar cell performances were studied with ultraviolet photoemission spectroscopy, atomic force microscopy, internal resistances in PPVs, and current–voltage power curves. The resultant PPVs with AuCl₃-treated PAN HELs showed improved cell efficiency compared to PSCs with no interlayer and PAN without AuCl₃. Furthermore, with AuCl₃-treated PAN, we finally achieved a high efficiency of 6.91%, and a desirable PPV-stability in poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b′]dithiophe-ne-2,6-diyl][3-fluoro-2-[(2-thylhexyl)carbonyl]-thieno[3,4-b]thiophenediyl]]:[6,6] phenyl-C₇₁ butyric acid methyl ester (PTB7:PC₇₁BM) solar cells, which is a comparable efficiency to the conventional devices with poly (3,4-ethylenedioxythiophen):poly (styrene sulfonate) (PEDOT:PSS), but showing better PPV-stability than PEDOT:PSS. (paper)