When it comes to conventional LCD screens, we don’t do any better than quantum light-emitting diodes, better known as quantum dots. While television manufacturers quickly seized on them, notably Samsung with its QLED range, Apple turned away from them for a long time, in particular because they contain toxic components. This changes with the screens of the new MacBook Pro M4s, which use a film of quantum dots cadmium-free, as noted by the display technology specialist Ross Young.
Of the quantum dots in solution. Image Polytechnic Institute of Paris.
Quantum light-emitting diodes are based on quantum dotssemiconductor structures comprising a few hundred to a few thousand atoms, which constrain electrons in a space measuring a few tens of nanometers. These little engineering marvels have opto-electronic properties that are sometimes reminiscent of traditional semiconductors, sometimes of individual molecules, in particular a phosphorescence whose color and intensity varies depending on the size and components of the quantum dot.
THE quantum dots are therefore particularly suitable for screens, where they make it possible to combine finesse (they measure between 2 and 10 nanometers) and richness (they can be available in the entire color spectrum), at the cost of slow and expensive manufacturing. Why has Apple, both a specialist in the industrialization of cutting-edge technologies and obsessed with display precision, never used them? Because they contain toxic components.
Depending on the desired color, the quantums dots contain cadmium selenide, cadmium sulfide, cadmium telluride, indium arsenide, indium phosphide, lead selenide or even lead sulfide. The Cupertino company therefore stuck to KSF phosphor films for the red layer of its screens, until the appearance of phosphor films. quantum dot cadmium-free, which produce more faithful colors.
THE perovskites seem to represent the future of quantum dots (and photovoltaic panels) and are notably used in certain mini-LED panels, the technology of the iPad Pro Liquid Retina XDR display. While she seems to have given up the idea of designing micro-LED screens in the short termfailing to have resolved the immense technical obstacles preventing their production on an industrial scale, has Apple found its new panacea?
