Dispenser printed composite thermoelectric thick films for thermoelectric generator applications

This paper describes novel processes for preparing thermoelectric composite materials compatible with thick film dispenser printing fabrication processes. Optimization of process parameters to improve thermoelectric properties is introduced. We explore the use of n-type ${\text{Bi}}_2{\text{Te}}_3$ and p-type ${\text{Sb}}_2{\text{Te}}_3$ materials to achieve properties suitable for use in low cost high aspect ratio microscale thermoelectric generators. Printable thermoelectric inks consisted of dispersed semiconductor powders in an epoxy resin system. Thick films were printed on glass substrates and cured at temperatures ranging from 150 to $350°\text{C}$ . The best achievable power factors for n-type ${\text{Bi}}_2{\text{Te}}_3$ -epoxy and p-type ${\text{Sb}}_2{\text{Te}}_3$ -epoxy composite films were $1.5\times {10}^{-4}\text{W}/\text{m}{\text{K}}^2$ and $8.4\times {10}^{-4}\text{W}/\text{m}{\text{K}}^2$ , respectively. Figure of merit (ZT) values for n-type ${\text{Bi}}_2{\text{Te}}_3$ -epoxy and p-type ${\text{Sb}}_2{\text{Te}}_3$ -epoxy composites were 0.16 and 0.41, respectively, which are much higher than previously reported ZT values for composite thermoelectric materials.