Harnessing activated carbon pores as growth templates for low-thermal-conductive thermoelectric films

초록

Copper indium selenide (CuInSe2) is a promising thermoelectric material; however, its application is often limited by interdependent electrical and thermal properties. In this study, we propose dual strategy to enhance the thermoelectric figure of merit (ZT) of CuInSe2 by utilizing the porous structure of activated carbon (AC) and elemental doping, followed by hybridization with conductive polymer. Mn-doped CuInSe2 particles were successfully synthesized within the pores of AC via a hydrothermal method, using the AC pores as growth templates. This unique architecture introduces numerous hetero-interfaces, significantly promoting phonon scattering. Consequently, the lattice thermal conductivity was effectively suppressed. To compensate for the low electrical conductivity of the porous composite, Mn was doped into CuInSe2 lattice to increase carrier concentration, and the resulting powder was composited with a PEDOT:PSS matrix to form a flexible film. The AC/Mn-CuInSe2/ PEDOT:PSS composite exhibited a significantly improved electrical conductivity of 116.19 S/cm compared to pristine CuInSe2 (0.079 S/cm). Furthermore, the thermal conductivity was drastically reduced to 0.24 W/mK at 373 K, which is approximately ten times lower. As a result, a maximum ZT value of 0.20 was achieved at 373 K. This work demonstrates an effective pathway to decouple electron and phonon transport for high-performance flexible thermoelectric materials.

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