What are Quantum Dots?

Quantum dots explained

In brief…

+  Quantum dots are semiconductor particles with typical diameter of 2–10 nm. They are so named because, due to their nanoscale size, quantum effects play a significant part in their light emitting properties. Quantum dots emit light via this mechanism: under external stimulus, some of the electrons of the dot material absorb sufficient energy to escape their atomic orbit. This creates a conductance region in which the electrons can move through the material, effectively conducting electricity. As these electrons drop back into atomic orbit, energy is released in the form of light, the color of which depends on the amount of energy released.

Because the light emissions are monochromatic, quantum dots have numerous existing and potential applications, including solar cells, medical imaging, and even quantum computing.

+  Because of the dots’ small size, the amount of energy released is relatively consistent from electron to electron, yielding emissions of a single color.

+  The color is entirely dependent upon the size of the dot, with larger dots (e.g., 5-6 nm) providing lower energy emissions (i.e., reds and oranges) and smaller dots (e.g., 2-3 nm) providing higher energy emissions (i.e., blues and violets). This property is sometimes referred to as “quantum confinement,” indicating that constraints at the atomic level are predominant.

Source:  EDN.  Yoelit Hiebert,  Quantum dots explained…

Content may have been edited for style and clarity.