copperselenium

Copper selenide, or copperselenium, refers to a class of inorganic compounds composed of copper and selenium. The most studied stoichiometries are copper(I) selenide CuSe and copper(I,II) selenide Cu2Se, though a range of non-stoichiometric copper selenide phases exist.

These materials crystallize in various structures depending on composition and temperature. Cu2Se is known for a high-temperature superionic phase where copper ions become highly mobile, leading to low thermal conductivity and favorable thermoelectric properties. CuSe and other phases are typically semiconductors with narrow band gaps, enabling light-absorption in the near-infrared.

Synthesis methods include solid-state reaction of elemental copper and selenium at elevated temperatures, chemical routes such as electrodeposition, solvothermal synthesis for nanostructures, and vapor-phase deposition for thin films. Phase stability and copper vacancy ordering strongly influence properties; small changes in copper content can induce phase transitions.

Applications include thermoelectric devices, where low thermal conductivity and decent electrical conductivity improve performance, photovoltaics and photoelectrochemical cells where CuSe-type materials act as p-type absorbers, and catalysis in certain redox reactions. Nanostructured copper selenide is explored for plasmonic and electrochemical applications.

Safety and environmental concerns should be noted: selenium compounds can be toxic, and copper selenides can release selenium or copper ions under oxidation or dissolution conditions. Proper handling, containment, and disposal per relevant regulations are advised.