Quantum Dots

A quantum dot is a semiconductor that exhibits tremendous capability despite the fact that they are so tiny: 2-10 nanometers. Because materials behave much differently when they are at this size, researchers hope that they will be able to make tremendous steps in many different applications of science and technology. Because of the size of them, the quantum dots provide the researcher with the ability to tune the dots to levels that have never been reached before.

To describe it in a much more straight forward manner, a quantum dot is a semiconductor that, depending on the size and shape of the crystal, exhibits different conductive characteristics. The way it works is complicated. With a very small crystal, there tends to be a larger band gap. Therefore, there is a greater difference in the energy between the highest valence band and the lowest conduction band. This results in a tremendous of energy being needed to cause the dot to enter an excited state. However, quantum dots become beneficial because when they return to a resting stage, they release a considerable amount of energy.

Uses of Quantum Dots

Right now in the scientific and technological world, there are four primary uses for quantum dots. However, as more research is revealed about them, other applications and other variants of the currently applications are applied. The four main uses for quantum dots are:

• Computing: Because of the size of the semiconductor, there is the ability to target a very specific amount of voltage. This allows for the exact measurement of the spin and other properties in the computer.
• Biology: One of the biggest applications is the use of quantum dots in imaging. In the past, doctors have used different dyes to pick up diseases in the body. The issue is that these dyes deteriorate over time and therefore, don't work as well. They are typically at 100 times more stable than fluorescent dyes and 20 times brighter than the dyes. This allows for doctors to see very exact areas of the body and to not deteriorate as time goes on. Another thing that they have found is that quantum dots are more effective at delivering to the siRNA a gene-silencing component than other currently employed methods.
• Photovoltaic Devices: What researchers have found is that a tiny quantum dots of lead selenide can produce up to seven excitons from a single photon of light from the sun. This is important because currently, the photovoltaic devices that are used can only get one exciton from a single photon of light. This has led some researchers to believe that they can increase efficiency by anywhere from 31-42%.
• Light Emitting Devices: Because there is considerable brightness to quantum dots, some researchers have used them to try and create light emitting devices. What they hope is that they cane use them for different LCDs because they can provide a much brighter and clearer picture.

As can be seen by the above applications, quantum dots are an important technological find that should continue to provide great advances in technology and medicine. While there is still room for growth, the discovery that was found by Louis E. Brus has brought tremendous advancements in fields of great importance.