Preparing two-dimensional crystalline conjugated polymer films by synergetic polymerization and self-assembly at air/water interface

Conjugated polymer (CP) films with high molecular order are attractive in polymeric optoelectronics, but challenging. Herein, we adopt a facile strategy including synergetic polymerization and self-assembly for crystalline CP films at a dynamic air/water interface. With poly(2,5-dihexyloxy-1,4-phenylenebutadiynylene) (poly-DHO-PBD) as one case shown from poly(butadiynylene) derivatives, large-area two-dimensional (2D) crystalline poly-DHO-PBD films with sizes of hundreds of micrometers and thicknesses down to tens of nanometers are successfully obtained from its 1,4-diethynyl-2,5-bis(hexyloxy)benzene (DEBHB) monomers by optimizing the interfacial Glaser-type reaction conditions, which can also be extended for the synthesis of four other poly(butadiynylene) derivatives. The high-quality crystalline CP films demonstrate efficient charge transport performance and excellent stability in electronic devices. This result opens a new avenue for preparing 2D crystalline CP films and would motivate increasing related lines of research on more complex functional CPs towards high performance polymeric optoelectronic devices and fundamental studies.