Flexible ball-milled Bi0.4 Sb1.6 Te3/methyl cellulose thermoelectric films fabricated by screen-printing method

Abstract

Flexible Bi[Formula: see text]Sb[Formula: see text]Te3 (BST)/methyl cellulose (MC) thermoelectric composite films were prepared by a two-step process: BST powders were successfully prepared via a ball milling method, and then BST/MC composite films with different volume fractions of BST were screen printed on flexible mixed cellulose esters membrane. As the contents of BST powders increased, the electrical conductivity was significantly improved, while the Seebeck coefficient was nearly unchanged, and a room temperature power factor (PF) of 2.32 [Formula: see text]W m[Formula: see text] K[Formula: see text] was achieved when the volume fraction of BST was 80%. After the cold-pressing treatment, both the electrical conductivity and Seebeck coefficient were improved, and a highest PF of 10.07 [Formula: see text]W m[Formula: see text] K[Formula: see text] was obtained at room temperature for the film with 80 vol.% BST, which was [Formula: see text]4.3 times higher than that of the pristine sample (2.32 [Formula: see text]W m[Formula: see text] K[Formula: see text] at room temperature). The tendency of thermoelectric performance varying with BST proportion was explained by the percolation threshold theory. This work shows the great potential of screen-printing technology in flexible and wearable electronics.