Quantum dots or QDs, which are also known as ‘artificial atoms,’ are specks of matter that are effectively concentrated at a single point. To put it in easier terms, these are zero-dimensional. Thus, the carriers of electricity are trapped and have well-defined energy levels build on the laws of quantum theory.
QDs crystals that are no more than 10 nanometers wide. These are made from semiconductors such as Silicon. A semiconductor can be used both as an insulator as well as a conductor when treated chemically. The small size of QDs displays optical and electronic properties which are different from the bulk materials. Thus, quantum dots applications are experiencing an upward trend.
How Do They Work?
QDs can be instrumental in controlling all kinds of useful things. When you provide energy to an atom, the electrons inside it gets boosted to a higher energy level. When they return to a lower level, a photon of light is emitted with the initially absorbed energy. Here, the wavelength and frequency of the light tend to depend on the type of atom used. For instance, sodium looks yellow, while iron looks green.
The difference in color can be owed to the arrangement of the energy levels in an atom. All this is because the energy levels are quantized; in other words, they have predetermined values.
These artificial atoms also work on the same principle. The dots made up of the same advanced material (e.g. graphene), but different in sizes will produce different frequencies and wavelengths and thus, different colors.
Applications of Quantum Dots
● Optical Applications
Because of their unusual optical properties, QDs have attracted a lot of interest. In places where precise control of colored light is required, these dots are viably being used.
They are also seen as a revolutionary technology in the development of more efficient solar cells. Not just this, but these are also finding their way into computer displays and screens. They are energy efficient, provide a much higher resolution image, and render much more realistic on-screen colors.
● Quantum Computing
A technology known as photonics aims at storing and transmitting information with light in place of electrons. QDs can serve a similar purpose in optical computers as transistors do in electronic computers.
In quantum computers, bits are stored by individual ions, atoms, photons, or electrons entangled together and acting as quantum bits known as qubits. These quantum scale “switches” can hold multiple values simultaneously and work on various problems parallelly. Though it is hard to control individual atoms in this manner, the artificial atoms are much simpler to work with when used at a considerably large scale.
● Biochemical and Chemical Applications
QDs are also being increasingly used for significant medical applications, including cancer treatments. Dots are designed to accumulate in specific parts of the body and then deliver anti-cancer drugs attached to them. The most significant advantage is that they can be targeted at single organs much more precisely than conventional medications. Thus, it diminishes the chances of side effects characteristic of traditional, untargeted chemotherapy.
Other than this, biological research is also replacing organic dyes with QDs at several places. For instance, to color specific cells using nanoscopic bulbs. In contrast to the organic dyes that degrade quickly and operate only over a limited range of colors, quantum dyes are bright, can produce any color, and last indefinitely.