Highly crystalline and semiconducting imine‐based two‐dimensional polymers enabled by interfacial synthesis

Abstract

Three crystalline imine‐based 2D polymer films are prepared by surfactant‐monolayer‐assisted interfacial synthesis (SMAIS). The synthetic PI‐2DP films feature polycrystalline multilayers with tunable thickness from 6 to 200 nm and large crystalline domains (100–150 nm in size) and exhibit p‐type semiconductor behavior with a band gap of 1.38 eV. Single‐layer and multi‐layer 2D polyimine films have been achieved through interfacial synthesis methods. However, it remains a great challenge to achieve the maximum degree of crystallinity in the 2D polyimines, which largely limits the long‐range transport properties. Here we employ a surfactant‐monolayer‐assisted interfacial synthesis (SMAIS) method for the successful preparation of porphyrin and triazine containing polyimine‐based 2D polymer (PI‐2DP) films with square and hexagonal lattices, respectively. The synthetic PI‐2DP films are featured with polycrystalline multilayers with tunable thickness from 6 to 200 nm and large crystalline domains (100–150 nm in size). Intrigued by high crystallinity and the presence of electroactive porphyrin moieties, the optoelectronic properties of PI‐2DP are investigated by time‐resolved terahertz spectroscopy. Typically, the porphyrin‐based PI‐2DP 1 film exhibits a p‐type semiconductor behavior with a band gap of 1.38 eV and hole mobility as high as 0.01 cm2 V−1 s−1, superior to the previously reported polyimine based materials.