Highly Efficient Nonfullerene Organic Solar Cells with a Self‐Doped Water‐Soluble Neutral Polyaniline as Hole Transport Layer

Among the various conducting polymers, polyaniline (PANI) has received a great deal of attention due to its low cost, excellent chemical and thermal stabilities, and high electrical conductivity. Herein, a newly designed self‐doped water‐soluble PANI derivatives‐poly (diphenylamine‐4‐sulfonic acid) (PDAS) is readily prepared and applied as hole extract layer in nonfullerene organic solar cells. PDAS, with satisfactory structural and electrical homogeneity, exhibits high conductivity of 7.75 × 10 −2 S cm −1 , none of acidity (with pH around 7), as well as enhanced work function of 5.43 eV, compared with the well‐known poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS). The power conversion efficiency of PDAS‐based devices is comparable with that of PEDOT:PSS‐based devices with the PM6:BTP‐4F‐12 as active layer. The successful design of the new self‐doped water‐soluble conductive polymer and its commercial application potential is demonstrated.