Colour conversion is already in consumer displays. Quantum-light sources ask a different question: how to control individual optical transitions.
Colloidal nanocrystals absorb blue light and re-emit selected colours. In a QLED LCD, they convert part of the LED backlight into narrow-band red and green light; a liquid-crystal layer still forms the image.
QD-OLED uses a different architecture: blue OLED emission supplies the light for quantum-dot colour conversion. Neither should be confused with a display in which current directly drives electroluminescence in the quantum dots themselves.
A single epitaxial or nanowire dot can act as a discrete quantum emitter rather than an ensemble colour converter. A biexciton–exciton cascade can provide a photon pair; producing entanglement additionally requires suitable level structure and coherence.
Our work connects this goal to crystal-phase nanowire emitters and electric-field control of exciton fine structure. A small splitting is a relevant design condition, not proof that a device emits entangled pairs.
Replacing cadmium-containing systems requires more than selecting a new band gap. Composition, interfaces and surface chemistry also affect confinement and light emission.
Our calculations for ZnCuInS/ZnS and ZnSe/ZnS address these atomistic effects. They inform materials design, but do not by themselves demonstrate a commercial display material or establish biological safety.
Quantum dots are used as fluorescent labels and investigated for sensing, photodetection and solar-energy conversion. Different applications place different demands on carrier localization, surfaces and charge transfer.
Confinement physics is shared across these systems; material choice, device architecture and practical constraints are not.
One name does not mean one technology. A colloidal nanocrystal in a television and a nanowire dot used as a single-photon emitter have different fabrication routes and device roles. The research presented here focuses on how their atomic structure and interactions shape the optical response.