Thermoelectric properties of p-type TTT2I3 organic crystals as a function of temperature

Abstract

Nanostructured organic materials of tetrathiotetracene-iodide (TTT2I3) are very prospective p – type thermoelectric material. The internal structure is pronounced quasi-one dimensional, with molecular chains spaced at ~1 nm one from other. The charge transport takes place mainly along the chains, with rare phonon-assisted jumps between the chains. Earlier, the thermoelectric properties of this organic compound were estimated numerically in the frame of a detailed physical model, considering the most important internal interactions, as well as the weak interchain interactions. It was demonstrated [1] that important results could be obtained in TTT2I3 crystals after optimisation of some internal parameters of the crystal. However, the mentioned results were obtained for room temperature. For real applications, it is very important to investigate the temperature effects of the thermoelectric characteristics of TTT2I3 crystals. The obtained results are indicating that the thermoelectric power factor can be significantly enhanced for a wide range of crystal temperatures.