Maintaining nanoimprinting-induced face-on alignment in poly(3-hexylthiophene) nanopillars after thermal annealing

Abstract

A key detail for conjugated polymers is to focus on the stability of the patterned nanostructure profile and the molecular alignment within the topography structure. We demonstrate here that the fabrication of a patterned poly(3-hexylthiophene) (P3HT) nanopillar film can be achieved by a simple and cost-effective solvent-assisted room-temperature nanoimprinting lithography (SART-NIL) method. This indicates that a face-on molecular alignment is induced in the nanostructure of the arrays of the nanopillars. In order to investigate the thermal stability of the P3HT nanopillar film, the effect of thermal annealing treatment on the nanostructure morphology and molecular alignment of the nanopillar film is performed here. This confirms that the thermal annealing plays a different role in the stability of the nanostructure morphology and molecular alignment for the P3HT nanopillar film. The stability of the patterned nanopillar profile significantly depends on the annealing temperature, however, the stability of the nanoimprint-induced face-on molecule alignment is immune to heating during annealing. The nanoimprint-induced face-on molecule alignment is maintained after the thermal annealing. In addition, the evolution of the surface topography and the molecule alignment during the thermal annealing is also investigated in detail.