The Seebeck Effect and In-plane Thermal Conductivity of a 2D Metal-organic Framework, Copper Benzenhexathiol: Potential Application to Thermoelectrc Devices

Copper benzenehexathiol (Cu-BHT) is a compound material categorized as metal-organic frameworks (MOFs), and it possesses unusually high electrical conductivity for MOFs [1]. MOFs form in a two-dimensional, thin film structure, and the thickness of our synthesized Cu-BHT film was down to sub-50nm with the lateral dimension of a few tens of microns. We measured the thermal conductivity, electrical conductivity, and Seebeck coefficient of the thin flakes of Cu-BHT. These measured quantities are relevant to the thermoelectric figure of merit, ZT, a measure of the efficiency of the energy conversion from heat to electricity. The ZT value of our Cu-BHT is relatively smaller as compared with Bi₂Te₃ but is still one of the highest values for MOFs [2]. Fortunately, one of the advangages of using MOFs as thermoelectric devices is that the thermal properties can be chemically modified easily. Owing to this easiness of the chemical doping, the ZT value of the Cu-BHT can be further improved by optimizing the Seebeck coefficient and electrical conductivity.

[1] X. Huang et al. Nat. Commun. 6, 7408 (2015)
[2] L. Sun et al. Joule 1, 168 (2017)