Semiconducting fused thiophene polymer ink formulation

A formulation comprising:

• an organic semiconducting polymer selected from the diketopyrrolopyrrole (DPP) and fused thiophene copolymer structures of the formulas (I), (II), or combinations thereof, or salts thereof, in an amount of from 0.1 to 5 wt % based on the total weight of the formulation:
• respectively,
• where
• m is an integer from 1 to 2,
• n is an integer from 4 to 80,
• X and Y are independently selected from a divalent heteroaryl,
• R1, R2, R3, and R4 is each a monovalent hydrocarbylene substituent independently selected from a group of a saturated or unsaturated, a branched or unbranched, a substituted or unsubstituted (C10-20)hydrocarbylene further substituted with a monovalent or divalent saturated or unsaturated cyclic or acyclic (C3-10)hydrocarbylene,
• a first solvent selected from a cyclic aliphatic in an amount of from 2 to 98 wt % based on the total weight of the formulation;
• and
• a second solvent selected from an aromatic in an amount of from 98 to 2 wt % based on the total weight of the formulation, wherein the volume ratio of the first solvent to the second solvent is from 75:25 to 25:75.