Berlin 2024 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 13: Poster I

HL 13.19: Poster

Monday, March 18, 2024, 15:00–18:00, Poster E

Theoretical insights into enhanced thermoelectric properties of TTT2I3 and TTT(TCNQ)2 organic nanostructured crystals — •Ionel Sanduleac and Silvia Andronic — Technical University of Moldova, Stefan cel Mare ave. 168, MD-2004, Chisinau, Republic of Moldova

We present a detailed analysis of the thermoelectric properties exhibited by crystals of TTT2I3, which manifests p-type behavior, and TTT(TCNQ)2 being an n -type conductor. These crystals have been shown to exhibit tunable thermoelectric properties through manipulations of the stoichiometry of charge carriers and impurity concentrations [1]. Crystals of TTT2I3, characterized by a layered structure of alternating tetrathiotetracene and iodide layers, demonstrates efficient charge transport along the main crystallographic axis. Similarly, TTT(TCNQ)2 shares the internal structure of TTT2I3, but with electric conductivity provided by electrons along the TCNQ chains. For this study, we developed a theoretical model, considering electron-phonon interactions and impurity scattering, to analyze transport and thermoelectric properties. The kinetic equation is derived using two-particle retarded Green functions. Electrical conductivity, Seebeck coefficient, thermoelectric power factor, and thermoelectric figure-of-merit were calculated numerically, as function of charge carrier concentrations, temperatures, and impurity concentrations. This study contributes to the understanding of organic thermoelectric materials and their potential role in sustainable energy applications.

[1] I. Sanduleac, et.al.: J. Appl. Physics, 126(17), (2019).

Keywords: Organic crystals; Thermoelectricity; Thermopower; Electrical conductivity; Thermal conductivity