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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 39: Organic Photovoltaics and Electronics II (joint session CPP/DS/HL, organized by HL)
CPP 39.8: Talk
Wednesday, March 22, 2017, 17:00–17:15, POT 81
Organic thermoelectrics based on low-dimensional molecular metals — •Alexander Steeger1, Florian Huewe1, and Jens Pflaum1,2 — 1Experimental Physics VI, Julius Maximilian University of Würzburg, 97074 Würzburg — 2Bavarian Center for Applied Energy Research (ZAE Bayern), 97074 Würzburg
Efficient recovery of waste heat by thermoelectric generators (TEGs) requires low-cost materials exhibiting high electrical conductivities σ and Seebeck coefficients S, but low thermal conductivities κ. The suitability of a given material for thermoelectric applications is quantified by the dimensionless figure of merit zT=σ S2 T/κ. In this contribution, we propose crystalline low-dimensional molecular metals as an alternative class of organic thermoelectric materials combining the advantages of low weight, chemical variety, sustainability, high charge carrier mobility and reduced electronic dimensionality with the availability of p- and n-type conductors. For the first time, we determined all physical quantities contributing to zT on exclusively one single crystal sample of p-type TTT2I3 and n-type (DMe-DCNQI)2Cu, revealing high power factors and promising figures of merit surpassing zT≥0.15 below 40 K. The thermoelectric performance of low-dimensional metals is affirmed by the power output per active area of a prototypical all-organic TEG reaching values of −0.9ex~ mW/cm2 and could be further increased by taking full control over the amount of charge-transfer and band filling. Financial support by the DFG (Project No. PF385/6-1) and the FP7 (H2ESOT, Project No. 308768) of the European Commission is gratefully acknowledged.