Poly(9,9-bis(3′-(N,N-dimethyl)-Nethylammonium-propyl-2,7-fluorene)-alt-2,7- (9,9-dioctylfluorene)) dibromide (PFN-Br) has been widely used as an cathode interface layer (CIL) for efficient organic solar cells (OSCs) because of its straightforward solution processability, excellent electron extraction ability, as well as prominent compatibility with various OSCs systems. However, the relatively low conductivity of PFN-Br results in CIL thicknesses usually
