Multicomponent semiconducting polymer systems with low crystallization-induced percolation threshold

Blends and other multicomponent systems are used in various polymer applications to meet multiple requirements that cannot be fulfilled by a single material. In polymer optoelectronic devices it is often desirable to combine the semiconducting properties of the conjugated species with the excellent mech. properties of certain commodity polymers. Here we investigate bicomponent blends comprising semicryst. regioregular poly(3-hexylthiophene) and selected semicryst. commodity polymers, and show that, owing to a highly favorable, crystn.-induced phase segregation of the two components, during which the semiconductor is predominantly expelled to the surfaces of cast films, we can obtain vertically stratified structures in a one-step process. Incorporating these as active layers in polymer field-effect transistors, we find that the concn. of the semiconductor can be reduced to values as low as 3 wt% without any degrdn. in device performance. This is in stark contrast to blends contg. an amorphous insulating polymer, for which significant redn. in elec. performance was reported. Cryst.-cryst./semiconducting-insulating multicomponent systems offer expanded flexibility for realizing high-performance semiconducting architectures at drastically reduced materials cost with improved mech. properties and environmental stability, without the need to design all performance requirements into the active semiconducting polymer itself.