Coordination polymers for emerging molecular devices

Abstract

Conductive coordination polymers are hybrid materials with the potential to be implemented in the next generation of electronic devices, owing to several desirable properties. A decade ago, only a few scattered examples exhibiting conductivity existed within this class of materials, yet today groups of coordination polymers possess electrical conductivities and mobilities that rival those of inorganic semiconductors. Many currently emerging energy harvesting and storage technologies are limited by the use of inefficient, unstable, and unsustainable charge transport materials with little tunability. Coordination polymers, on the other hand, offer great electrical properties and fine-tunability through their assembly from molecular building blocks. Herein, the structure–function relationship of these building blocks and how to characterize the resulting materials are examined. Solution processability allows devices to step away drastically from conventional fabrication methods and enables cheap production from earth abundant materials. The ability to tune the electrical and structural properties through modifications at the molecular level during the material synthesis stages allows for a large design space, opening the door to a wide spectrum of applications in environmentally friendly technologies, such as molecular wires, photovoltaics, batteries, and sensors. Sustainable, high-performing charge transport materials are crucial for the continued advance of emerging molecular technologies. This review aims to provide examples of how the promising properties of coordination polymers have been exploited to accelerate the development of molecular devices.

Plastic bending in a semiconducting coordination polymer crystal enabled by delamination

“…Coordination polymers (CPs), as a class of crystalline solids consisting of metal nodes and organic linkers, are at the forefront of materials science as they offer enormous application potential in electronics 1 , magnetics 2 , and optics 3 . However, their single crystals, constructed by directional coordination bonds, are intrinsically brittle, which severely limits their utility in applications such as flexible electronics and smart wearable devices 4 , 5 . It has been recently demonstrated that bendable organic crystals could be applied as deformable optical waveguides and circuits 6 , flexible conductors 7 , and ferroelectrics 8 .…”

Conductivity in Thin Films of Transition Metal Coordination Complexes

“…The conductivity was determined by preforming a current–voltage sweep using a four-point contact method to a film, deposited from solution via drop casting on an interdigitated finger pattern. The detailed approach, in addition to the operational principles of the interdigitated finger pattern, is provided in the Supporting Information and in Morritt et al 27 The current–voltage sweeps for Ni–Cu and Cu–Cu are shown in full in Figure S4 of the Supporting Information. The Cu–Cu data shows a clear linear pattern with a degree of hysteresis, with the value of conductivity calculated as approximately 2.5 × 10 –8 S cm –1 .…”

Insight into the Structural and Emissive Behavior of a Three‐Dimensional Americium(III) Formate Coordination Polymer

“…All of these factors are known to influence the resulting material properties. [39][40][41][42][43] The small size of the formate ion, however, prevents the formation of solvent accessible void spaces, reducing the complexity of the structure and properties associated with host-guest interactions. As such, compounds that utilize formate linkers represent the simplest type of a 3-D framework and may serve as a baseline model to interpret periodic trends and properties such as spectroscopic signatures.…”

“…Because of the number of possible coordination modes, MOFs and coordination polymers experience significant differences in framework structure, void spacing, and metal–ligand bond strength. All of these factors are known to influence the resulting material properties [39–43] . The small size of the formate ion, however, prevents the formation of solvent accessible void spaces, reducing the complexity of the structure and properties associated with host‐guest interactions.…”