Intrinsic glassy-metallic transport in an amorphous coordination polymer

Abstract

ParagraphConducting organic materials, such as doped organic polymers, 1 molecular conductors, 2, 3 and emerging coordination polymers, 4 underpin technologies ranging from displays to flexible electronics. 5 Realizing high electrical conductivity in traditionally insulating organic materials necessitates tuning their electronic structure through chemical doping. 6 Furthermore, even materials that are intrinsically conductive, such as single-component molecular conductors, 7,8 require crystallinity for metallic behavior. However, commercial conducting polymers are often purposefully amorphous to aid in durability and processability. 9,10 Using molecular design to engender high conductivity in undoped amorphous materials would enable tunable and robust conductivity in many applications, but there are no intrinsically conducting organic materials which maintain high conductivity when disordered. Here we show that the completely amorphous coordination polymer Ni tetrathiafulvalene tetrathiolate (NiTTFtt) displays intrinsic metallic conductivity. Despite its disordered structure, NiTTFtt exhibits remarkably high electronic conductivity (1280 S/cm) and intrinsically glassy metallic behavior. Analysis with advanced theory shows that these properties are enabled by strong molecular overlap and correlation that are robust to structural perturbations. This unusual set of structural and electronic features results in remarkably stable organic conductivity which is maintained in air for weeks and at temperatures up to 140 °C. Our results demonstrate that molecular design can enable metallic conductivity even in heavily disordered materials. This both raises fundamental questions about how band-like transport can exist in the absence of periodic structure as well as suggests exciting new applications for these materials.

Pair distribution function analysis of discrete nanomaterials in PDFgui

“…As the present approach may increase the number of independent structural parameters, care should be taken to impose appropriate constraints during the refinement. In the case of two-and one-dimensional nanomaterials, it may be appropriate to apply symmetry constraints within the layer or chain (Beauvais et al, 2021;Xie et al, 2022). For very large or complex models, it may be more appropriate to use this approach to simulate PDFs for different candidate models for comparison with experimental data (Vicchio et al, 2023) or impose constraints based on chemistry or complementary experimental data (e.g.…”

“…This composite PDF is based on a twocomponent model that simulates the contributions from the atomic correlations and local number density (or 'baseline') using separate phases with the same atomic arrangement. This approach has been successfully applied to simulate the PDF for clusters dispersed in solution (Vaughn et al, 2021) and supported on solid materials (Vicchio et al, 2023), as well as low-dimensional nanomaterials (Beauvais et al, 2021) and individual polymeric strands within a glassy conductive polymer (Xie et al, 2022).…”

Efficient and air-stable n-type doping in organic semiconductors

“…[22][23][24][25][26][27] Very recently, highperformance organic thermoelectric (OTE) materials are obtained by doping of OSCs to increase carrier concentrations and electrical conductivities, which reach device performances comparable to inorganic TEs at low/medium temperature regions. [28][29][30][31][32][33][34][35][36] To achieve efficient chemical doping, frontier molecular orbital energy levels, and charge-transfer process in the dopants/OSCs binary system should be carefully considered. [37][38][39][40][41] Moreover, good miscibility in this binary system is required to obtain high doping levels (Fig.…”

“…18. 36,[113][114][115][116][117] The unique p-d electrons overlap and the large bandwidth in these coordination polymers enables intrinsically high electrical conductivity. Without external chemical doping, these coordination polymers showed excellent air stability.…”

Quantum Many-Body Theory from a Solution of the N -Representability Problem

“…More recently, the author [10] showed that the complete N -representability conditions are derivable from convex combinations of higher-particle, constraint matrices. In the past decade approximate conditions have been employed in variational calculations of the 2-RDM to solve significant problems such as the elucidation of the electronic properties of a glassy, highly conductive amorphous polymer [38] and the revelation of exciton condensation in molecular analogs of double-layer graphene [39][40][41][42] (refer to Refs. [43][44][45][46][47][48] for their use in one-particle RDM functional theories).…”