| Abstract: | A series of copolymers of thiazoloisoindigo(Tzll)with different chalcogenophene trimers were synthesized to systematically investigate the chalcogen effect on their charge transport properties.When only the middle thiophene ring of terthiphene(T-T-T)is replaced by heavier chalcogenophenes,a preference(expressed by the ratio of μe/μh)towards electron transport was observed descending from T-T-T to T-Se-T then to T-Te-T(Se and Te stand for selenophene and tellurophene,respectively).On the other hand,with the increased number of heavier chalcogenophenes,a preference toward hole transport was observed descending from Se-T-Se to Se-Se-Se then to Se-Te-Se.This phenomenon is well-explained by the balance between the aromatic resonance energy of the chalcogenophenes and the electronegativity of the chalcogens.Specifically,P(Tzll-T-Se-T)displayed relatively balanced ambipolar property(μhmax and μemax of 3.77 and 1.59 cm2·V-1·s-1 with a μe/μh of 0.42),while P(Tzll-Se-Te-Se)exhibited the best preference to hole transfer with a μe/μh of 0.09.P(Tzll-T-Te-T)exhibited the best preference to electron transfer with a μe/μh of 16 and the μemax of 0.64 cm2·V-1·s-1 which is the highest electron mobility among the known conjugated polymers containing tellurophenes. |
