Strain-regulated electronic properties of helical polymer with phenylacetylene monomers-a first principle study

Helical polymers, a class of organic polymers with a unique spring-like structure, possess interesting electronic configurations and axial quantum transport properties thanks to the tunable interlayer electronic interaction by strain engineering. In this report, we carried out first-principle calculations to investigate the electronic structures and transport properties of the helical polymer with phenylacetylene monomers under compressive strains. The band structures of the material show a remarkable semiconductor-to-metal phase transition and enhanced electronic dispersion caused by the great interlayer coupling when subjected to an increasing compressive strain. During compression, the conduction band minimum and valence band maximum gradually move closer to the Fermi level and eventually pass through the Fermi surface. Moreover, under large strains, a notable overlap between interlayer electron clouds makes an effective channel for the axial electron transmission, explaining the greatly improved charge transport properties. This improvement is mainly due to the formation of the interlayer transmission channels through sigma bonds. Our findings on the strain-regulated electronic properties of helical polymers suggest there are great potential applications of these materials in high-performance sensors and flexible electronic devices.