Quantum Dots are crystals of semiconductors with nanometric – a billionth of meter – dimensions. They are constituted of few hundreds to few thousands of atoms regularly stacked to form a nanocrystal. They are synthesized in solution during a controlled process of nucleation and growth.
Quantum Dots have unique optical and electronic properties intrinsically related to their size. More precisely the electron and the hole formed by the absorption of a photon inside a Quantum Dot are confined by the geometrical dimensions of the particle. This confinement gives strong size-dependent optical and electronic properties.
Size-dependent fluorescence is one of the key feature of Quantum Dots. Almost each color of the rainbow can be obtained by just changing the size of the Quantum Dot core from approximatively 2 to 6 nanometers. For a given composition, the smaller Quantum Dot will emit in the blue, and the bigger in the red.
Quantum Dots are commonly spherical but their shape can be modified to confer them original properties; the composition of the crystal itself is also important. The ability to tune the dimensionality and the properties of Quantum Dots makes them very attractive for a wide range of applications.