Processable High Electron Mobility π‐Copolymers via Mesoscale Backbone Conformational Ordering

The synthesis and experimental/theoretical characterization of a new series of electron‐transporting copolymers based on the naphthalene bis(4,8‐diamino‐1,5‐dicarboxyl)amide (NBA) building block are reported. Comonomers are designed to test the emergent effects of manipulating backbone torsional characteristics, and density functional theory (DFT) analysis reveals the key role of backbone conformation in optimizing electronic delocalization and transport. The NBA copolymer conformational and electronic properties are characterized using a broad array of molecular/macromolecular, thermal, optical, electrochemical, and charge transport techniques. All NBA copolymers exhibit strongly aggregated morphologies with significant nanoscale order. Copolymer charge transport properties are investigated in thin‐film transistors and exhibit excellent electron mobilities ranging from 0.4 to 4.5 cm2 V−1 s−1. Importantly, the electron transport efficiency correlates with the film mesoscale order, which emerges from comonomer‐dependent backbone planarity and extension. These results illuminate the key NBA building block structure–morphology–bulk property design relationships essential for processable, electronics‐applicable high‐performance polymeric semiconductors. High electron mobility copolymer semiconductors are realized through control over conjugated backbone planarity and order using the naphthalene bisamide (NBA) building block. NBA favors highly planar backbone conformations; thus, comonomers that limit torsional displacement and disorder correlate to enhanced copolymer morphological order across multiple length scales and electron mobilities ranging from 0.4 to 4.5 cm2 V–1 s–1.