A polymer is provided. The polymer has a repeating unit having a structure represented by Formula (I) or Formula (II) wherein Ar1 and Ar2 can be substituted or unsubstituted aryl diradical; Y− can be R2SO3− or ClO4−; R1 can be C1-6 alkyl; Ar1 and Ar2 are different; and, R2 can be C1-6 alkyl, substituted or unsubstituted aromatic ring, or C1-6 haloalkyl.