01 · The discovery
The idea, in everyday language
A large piece of semiconductor has fairly predictable properties. Shrink it to a crystal only a few nanometres across and the space available to its electrons changes which energies are allowed.
Yekimov found size-dependent effects in glass; Brus found them in particles floating in liquid. Bawendi developed a reliable way to make high-quality dots of controlled sizes. For a given material, smaller dots generally emit higher-energy, bluer light and larger dots redder light.
See the idea
Size changes the light
Change the size of the crystal.
For the same semiconductor, a smaller dot generally emits higher-energy, bluer light. This is a qualitative illustration, not a calibrated colour or energy prediction.
Why it matters
Quantum dots are used to produce vivid colours in displays and as fluorescent labels in research. Their usefulness depends on controlling both their chemistry and their size.
