Quantum dots are small semiconducting nanocrystals
that can be made up of a variety of different elements, such as silicon, cadmium selenide,
or cadmium sulfide. They range in size from 2 to 10 nanometers. 1 nanometer is about the
width of 2 silicon atoms. These semiconducting materials are able to absorb light. When they
release that energy, they transform it into different color of light. The specific color
that a quantum dot will produce depends mostly on the size and material of the quantum dot.
The reason for this is something called quantum confinement. The effect is similar to that
of two different size bells. When the larger one is struck, the result will be low energy
sound waves *bell sound*, while the smaller one creates higher energy waves *bell sound*.
When light excites a quantum dot, the larger the size of the dot, the lower the energy
waves will be, resulting in a redder light. The smaller it is, the bluer the light will
be. Quantum dots are used in medical research as well as in solar panels, televisions and
solid state lighting.