Two dimensional semiconducting polymers

Abstract

<p>Synthetic chemistry towards two-dimensional semiconducting polymers (2DSPs) with planar π-conjugated structures is reviewed and their unique chemical and physical properties derived from the extended π-conjugation are discussed.</p>

Emergent Spin Frustration in Neutral Mixed-Valence 2D Conjugated Polymers: A Potential Quantum Materials Platform

“…These materials tend to have fairly low strength AFM interactions (J ∼−250 K = −21.5 meV) and their nonbonded arrays of molecular spin-carrying nodes are susceptible to thermal disruption due to the weak cohesive intermolecular forces taking place. In contrast, mv-2DCPs are based on robust and highly symmetric covalently linked sp 2 based 2D lattice which can host significantly stronger AFM interactions. The low spin−orbit coupling in our sp 2 -based magnetic states also inhibits spin canting, which can lead to competing nonfrustrated spin orderings.…”

“…In contrast, mv-2DCPs are based on robust and highly symmetric covalently linked sp 2 based 2D lattice which can host significantly stronger AFM interactions. The low spin−orbit coupling in our sp 2 -based magnetic states also inhibits spin canting, which can lead to competing nonfrustrated spin orderings. 37 Several experimental realizations of 2D spin lattice systems (e.g., square lattice in cuprates, the honeycomb lattice, or the frustrated triangular or kagomélattices) have shown interesting quantum phases at low temperatures, such as superconductivity, QSL-based phases, or topological quantum states.…”

“…36 Predictions of the pure Heisenberg model may also be affected by spin−orbit coupling, which can lead to spin canting competing with frustration via Dzyaloshinskii−Moriya interactions. 37 The lack of significant spin−orbit coupling in organic sp 2 -based systems would tend to rule out noncollinear canted spin states in our mv-2DCPs. Specifically, we note that electron paramagnetic resonance measurements on the molecular analogues of both B-mv-2DCP and N-mv-2DCP can be well fitted using the Bleaney−Bowers equation, which is purely based on a two-body Heisenberg model (i.e., isotropic spin exchange coupling).…”

“…Two-dimensional conjugated polymers (2DCPs) are based on planar networks of trigonal sp 2 nodes and are an emerging class of organic materials with a wide range of potential device applications. − Graphene, a 2D hexagonal array of carbon sp 2 nodes, is the most celebrated 2DCP largely due to its semimetallic band structure with Dirac-like linear band crossings at the Fermi level ( E F ), and concomitant high electron mobilities . However, as graphene does not display a band gap, it is not a suitable platform for switchable electronic devices.…”