In recent years, there has been special interest in developing devices capable to harvest and store energy from natural resources without the generation of pollution. Thermoelectric generator (TEG) is an emergent technology to harvest energy, especially in those environments in which heat waste is involved. These solid-state devices are capable of generating an output voltage as a function of a temperature difference. The efficiency of a TEG is evaluated through the dimensionless figure of merit, Z. In order to achieve a competitive the figure of merit, a material with a high Seebeck coefficient, electrical conductivity and low thermal conductivity is desirable. Conductive metal organic frameworks (c-MOFs) are hybrid materials composed of inorganic and organic building blocks, in which metal nodes are coordinated to highly conjugated organic linkers.The overlap between the metal and ligand frontier orbitals facilitates the charge transport in these materials. Porosity and heterogeneity in atomic species and linkers are features that have led to a predictably low thermal conductivity, a key aspect to optimize Z, making MOFs potential candidates for TEG. In this work we present an electrochemical approach to the growth of conducting thin films of the 2D c-MOF Cu3(HHTP)2 (where HHTP = 2,3,6,7,10,11-hexahydroxytriphenylene). Bulk Cu3(HHTP)2 was synthesized solvothermally according to the literature and we have subsequently fabricated thin films of this important framework by anodic electrochemical synthesis. We report the first thermoelectric measurements of this framework both in bulk and thin film form which resulted in Seebeck coefficients of -7.24 μV K-1 and -121.4 μV K-1 with a power factor of 3.15x10-3 μW m-1 for the film respectively. The study of conducting MOFs and their performance as TEG is expected to expand and offer alternatives to non-toxic, scalable and high-efficiency novel TEG materials.

Electrochemical deposition and thermoelectric characterisation of a semiconducting 2-D metal-organic framework thin film

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.