Fully Printed 3D Tin Selenide (SnSe) Thermoelectric Generators with Alternating n-type and p-type Legs

Tin selenide (SnSe) has attracted much attention in the field of thermoelectrics since the discovery of the record figure of merit (zT) of 2.6 ± 0.3. Whilst there has been many publications of p-type SnSe, to manufacture efficient SnSe thermoelectric generators n-type is also required. Publications on n-type SnSe, however, are limited. This paper reports a pseudo 3D-printing technique to fabricate bulk n-type SnSe elements, by utilising Bi as a dopant. Various Bi doping levels are investigated and characterised over a wide range of temperatures and through multiple thermal cycles. Stable n-type SnSe elements are then combined with printed p-type SnSe elements to fabricate a fully printed alternating n- and p-type thermoelectric generator, which is shown to produce 145 µW at 774 K.