What are quantum dots?

Quantum dots are incredibly small semiconductor particles, typically measuring just a few nanometers in diameter. One of their defining characteristics is their ability to emit specific colors of light when energized. This light emission is a result of quantum confinement effects, which means that because these particles are so small, the electrons inside them behave differently compared to those in bulk materials.

When energy is applied to quantum dots—such as from light or electrical current—they can absorb this energy and then re-emit it. The color of the light they emit is primarily determined by their size; smaller quantum dots emit light at shorter wavelengths (like blue), while larger ones emit at longer wavelengths (like red). This property of quantum dots has made them highly valuable in various applications, including displays, solar cells, and biological imaging, where specific and tunable light emission is essential.

In contrast, the other options refer to different concepts or materials: large semiconductor crystals are not nanoscale and have different applications, while composite materials involving organic compounds do not specifically relate to the unique light-emitting properties characteristic of quantum dots. Nanoscale particles that can trap energy might indicate a different type of nanostructure, but they do not define quantum dots accurately. Thus, the identification of quantum