Two-Dimensional Growth of Large-Area Conjugated Polymers on Ice Surfaces: High Conductivity and Photoelectrochemical Applications.

Polymerizing monomers on an atomically flat solid surface and air/water, solid/liquid, or liquid/liquid interface is now a rapidly emerging frontier. Dimension-controlled synthesis of π-conjugated polymers is of particular interest, which can be achieved by precise control of monomer distribution during the polymerization. The surface of ice allows rapid polymerization of monomers in the plane direction along the air-water interface to yield large-area two-dimensional sheet-like poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (2D sheet-like PEDOT:PSS) films with a thickness of ca. 30 nm. The persuasive role of ice chemistry is reflected in the high degree of crystallinity and superior conductivity of resultant PEDOT:PSS films. Excellent photoelectrochemical features were further disclosed when the ice-templated PEDOT:PSS films were coupled to quantum dots. Utilization of these polymer films in photovoltaic devices also resulted in excellent current density and power conversion efficiency. This work presents an innovative material technology that goes beyond traditional and ubiquitous inorganic 2D materials such as graphene and MoS2 for integrated electronic applications.