Samsung Electronics claims to have produced the first large-area, full-colour display based on red, green and blue quantum dots. Making a colour display with the dots requires their deposition onto a substrate in a well-controlled manner.
Structure
The dots contain a zinc sulphide shell that confines electrons and holes to the core of the structure made of a cadmium-based compound. Both charge carriers are restricted in all three spatial dimensions on length scales which restricts the energies of electrons and holes to a finite set of values, so that when these carriers reach their lowest energy state, they recombine to emit light having very narrow emission profile.
Display
Monochrome displays can be made by spin-coating. This is done by dropping a dot-containing solution onto a substrate and spinning this around to yield a thin film of material. This approach is unsuitable for making a full-colour display, because it would cross-contaminate red, green and blue pixels. Higher resolution displays are possible by reducing pixel size. Huge size printing onto flat or curved surfaces is possible by scaled up Transfer-printing to even in the shape of rolled plastic sheets.