As an interesting aside, right now bright OLED screens have pretty bad wear characteristics. We do have a cheap solution that would work, but it requires cadmium.
A decade ago or so there was an application for RoHS exemption for the use of cadmium in displays, and their argument was that because coal plants emit cadmium, and because Oled screens with cadmium quantum dots are so much more efficient than backlit screens, that in practice allowing the use of cadmium in screens would reduce total cadmium release into the environment. It didn't pass.
A decade ago or so there was an application for RoHS exemption for the use of cadmium in displays, and their argument was that because coal plants emit cadmium, and because Oled screens with cadmium quantum dots are so much more efficient than backlit screens, that in practice allowing the use of cadmium in screens would reduce total cadmium release into the environment. It didn't pass.