The European Commission has granted an exemption to the Restriction of Hazardous Substances (RoHS 2) Directive for Electrical and Electronic Equipment (EEE) to QD Vision for its cadmium-based quantum dots. The EC stated, ‘Colour-converting LEDs using quantum dots have significant advantages regarding energy efficiency and colour performance… The use of quantum dots in displays has a positive overall impact due to their low energy consumption. The use of cadmium in downshifting cadmium-based semiconductor nanocrystal quantum dots for use in display lighting applications should therefore be exempted from the prohibition until 30th June 2018′.
We covered this topic in some detail in our SID 2014 report. QDs help to boost efficiency and so reduce power usage. Power generation puts cadmium and other noxious materials into the environment, so as long as cadmium use is less than what would be produced by power generation, exemptions are granted. This was the logic behind the exemption for mercury in CCFLs.
The other factor is whether there is an alternative. At one point, only Nanoco had cadmium-free QDs, but it has been joined by Nanoco.