Figure 4. Effect of coating speed and of molecular weight.

a) Saturation mobility (V_GS = V_DS = 60 V) for FETs fabricated by bar-coating at different velocity (1, 3, 6 m min⁻¹) a solution of P(NDI2OD-T2) with M_n of 26.6 KDa and PDI of 3.2, probing the transport parallel (black dots) and perpendicularly (red dots) to the coating direction. The solution concentration is 5 g l⁻¹ in mesitylene. b) Saturation mobility (V_GS = V_DS = 60 V) for FETs fabricated by bar-coating solutions of P(NDI2OD-T2) with different M_n and PDI, probing the transport parallel (black dots) and perpendicularly (red dots) to the coating direction. Solution concentration (5 g l⁻¹ in mesitylene) and coating speed (3 m min⁻¹) were kept constant.