Possibilities to Improve the Thermoelectric Properties of n-type Organic Crystals

Abstract

In the last years, organic materials attract more and more attention for thermoelectric applications as materials with more diverse properties, accessible row components and obtained by cost- effective environmentally friendly production technology. For the thermoelectric converters materials of both p - and n-type are necessary. Usually, the materials of n-type have lower values of the thermoelectric figure of merit ZT, then those of p-type. Therefore, it is important to search materials of n- type with improved thermoelectric performance. In this paper, the thermoelectric properties of n- type organic crystals of tetrathiotetracene –tetracyanoquinodimethane, TTT(TCNQ)2, are modeled and optimal parameters in order to increase ZT are determined. It is obtained that, if the carrier concentration is increased by 2.3 times with respect to stoichiometric one and the crystals are further purified, values of ZT ~ 1.2are expected, higher than reported until now in organic crystals of n-type.