By the 1860s, Moses G. Farmer, an American inventor, had developed the first high powered thermoelectric generator based on using a zinc-antimony alloy with a composition very close to stoichiometric ZnSb.

He showed this generator at the 1867 Paris Exposition where it was carefully studied and copied (with minor modifications) by a number of people including Clamond.

George H. Cove patented a thermoelectric generator based on a Zn-Sb alloy in the early 1900s.

This was a far higher output than would be expected from a thermoelectric couple, and was possibly the first demonstration of the thermophotovoltaic effect, as the bandgap for ZnSb is 0.56eV, which under ideal conditions[according to whom?]

[citation needed] The next researcher to work with the material was Mária Telkes while she was at Westinghouse in Pittsburgh during the 1930s.