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IYPT Elements

IYPT 2019 Elements 052: Tellurium: Solar cells, discs and photocopiers

Element 52 in our International Year of the Periodic Table series is tellurium. This element is found in some types of solar cells, DVD and Blu-Ray discs, and photocopiers.

Cadmium telluride is used to make some solar cells. These cells accounted for 8% of all solar cells in 2011. Tellurium isn’t a particularly abundant element in the Earth’s crust, which contributes to the cost of solar panels made of these cells. Despite this, it’s been estimated that they have the shortest payback time of any current solar cells. However, there is some concern regarding the toxic cadmium content (while cadmium telluride is significantly less toxic than elemental cadmium, it’s still a potential environmental concern if the panels are disposed of).

DVDs and Blu-Ray discs have a coating of tellurium suboxide as part of their recording layer. The discs are originally written to by a laser beam which creates pits in the tellurium layer to record data.

Selenium-tellurium alloys are used in some photocopiers, and help to improve picture quality. In many cases, they’ve now been superseded by organic photoconductors.