Tin selenide, also known as stannous selenide, is an inorganic compound with the formula SnSe. Tin(II) selenide is a narrow band-gap (IV-VI) semiconductor structurally analogous to black phosphorus. It has received considerable interest for possible applications including low-cost photovoltaics, and memory-switching devices. Because of its low thermal conductivity as well as reasonable electrical conductivity, tin selenide is one of the most efficient thermoelectric materials.