  Currently, one of the major nanotechnological challenges is to design
thermoelectric devices that have a high figure of merit. To that end, we
propose to use bilayer excitons. Bilayer exciton systems are shown to have an
improved thermopower and an enhanced electric counterflow and thermal
conductivity, with respect to regular semiconductor-based thermoelectrics. Here
we present a roadmap towards experimental realization of a bilayer exciton
thermocouple. A bilayer exciton heterostructures of $p$- and $n$-doped
Bi$_2$Te$_3$ can have a figure of merit $zT \sim 60$. Another material
suggestion is to make a bilayer out of electron-doped SrTiO$_3$ and hole-doped
Ca$_3$Co$_4$O$_9$.
