Selenium

In 1817, Swedish chemist Jöns Jacob Berzelius, together with Johann Gottlieb Gahn, discovered a red substance derived from sulfide ores in the mines of Falun, Sweden. The following year, it was identified as an element similar to tellurium and was named selenium, after Selene, the Greek goddess of the Moon.

Later, the different forms of selenium were studied — red amorphous selenium and gray metallic selenium.

Selenium was first used in the glass industry for coloring and decolorizing glass. In 1873, Willoughby Smith discovered the photoconductivity of selenium.

From the early 20th century, selenium rectifiers were developed for use in old radios, along with the first selenium-based solar cells. In 1938, Chester Carlson used selenium photoconductors to create the first modern photocopier. In 1957, selenium was recognized as an essential trace element for humans.

Today, selenium plays an important role in photovoltaics and nanotechnology.

The main applications of selenium are in photovoltaics and electronics. It is a key component of copper indium gallium selenide (CIGS) solar cells, an efficient thin-film photovoltaic technology.

Selenium is also used in the glass industry for decolorizing as well as for producing red coloration in glass and ceramics.

Selenium coatings protect metal surfaces from corrosion.

In addition, selenium is used as an alloying element in copper and steel, improving machinability and reducing wear.

The largest selenium reserves are found in China, Russia, Canada, and Chile. There are no dedicated selenium mines; the element is obtained as a by-product during the refining of copper, lead, and other metals.

China is the dominant producer, followed by Japan, Germany, and Russia as other major producing countries.

The world’s largest selenium producer is Jiangxi Copper, located in Guixi, Jiangxi Province, China, with an annual output of several hundred tonnes. Tongling Nonferrous Metals Group is another key player in the global selenium market. In Japan, Mitsubishi Materials is the leading selenium producer, while Aurubis in Hamburg, Germany, is the largest selenium producer in Europe.

The importance of recycling, particularly from old photocopiers and electronic waste, is increasing.

Global selenium production amounts to approximately 3.500 tonnes per year.

The complete substitution of selenium in photovoltaics is unlikely, as copper indium gallium selenide (CIGS) solar cells offer high efficiency. Although CIGS cells can be replaced by perovskite, cadmium telluride, or kesterite solar cells, these alternatives often involve significant trade-offs in terms of efficiency or stability.

Manganese and cobalt can partially replace selenium in decolorizing applications.

The substitution of selenium–cadmium red (ruby glass) is possible with cerium sulfide, iron oxide–based pigments, or gold nanoparticles. However, selenium–cadmium red remains unmatched in terms of brilliance, heat resistance, and cost efficiency.