Como funcionam os QUANTUM DOTS?

Why do we see an apple as red and trees as green? When we look at most objects, they appear colored because natural sunlight or artificial light from lamps reflects off them in waves of light formed by photons. The incident photons scatter off the objects and are captured by your eyes, which function as detectors.

But when you watch TV, where do the colors come from? Currently, on most TV screens, colors come from a series of small lights called Light Emitting Diodes (LEDs). These LEDs emit three basic colors: red, green, and blue.

To achieve other colors, the LEDs combine these three basic colors in various proportions. Since LEDs emit three colors with broad color profiles, they may struggle to represent them with high precision. On the other hand, Quantum Dots, or "QUANTUM DOTS" in English, are a new technology capable of emitting colors much more accurately.

Quantum dots are microscopic and have nanoscale dimensions. The size of a quantum dot compared to a human is like the size of a human compared to the Sun. They are made of materials called semiconductors that have special properties, hence the name "nanocrystalline semiconductors.

" Semiconductors have energy bands through which electrons can move. When a photon hits an electron, the electron absorbs the energy from the photon and jumps to a higher energy band. To return to a lower energy band, the electron can emit a photon corresponding to that energy difference.

This means that the difference between the two energy levels determines the energy of the emitted photon, which is related to the color of the light that will be emitted. In other words, QUANTUM DOTS are specific color light emitters. It is possible to change the size of quantum dots to adjust the energy difference between the two bands and change the color of the light emitted by the quantum dot.

Smaller quantum dots have a larger energy difference between the bands. To return completely to the lower energy band, electrons must emit a high-energy photon, creating colors with short wavelengths, like blue or violet. This is because the higher the energy of the emitted photon, the shorter the observed wavelength of light.

Larger quantum dots have smaller energy differences between these bands, and these "larger" dots emit lower energy light with longer wavelengths, creating shades of yellow or red. There is a lot of research related to creating high-efficiency quantum dots. Many newer TVs nowadays use quantum dots because they produce purer colors more efficiently in terms of energy than LEDs used in conventional TVs.

However, quantum dots can be used for much more than just TV screens. With more precise colors, astronomers can collect more accurate data about the light spectrum coming from distant stars, providing more accurate readings of the age and composition of objects. Additionally, quantum dots can be used to capture sunlight and convert it into electricity.

Scientists are also using quantum dots to develop better medical imaging methods. Quantum dots can improve current technology using dyes or other imaging agents to visualize cancerous tumors, providing better differentiation between cancerous and healthy tissues. Surgeons could operate with greater precision, helping to preserve the patient's healthy tissue.

However, more research needs to be done to determine if quantum dots are safe for use in humans. One advantage of using quantum dots is their nanoscale size, which allows them to be dispersed in liquids in the form of colloids. Therefore, many liquid processing techniques like inkjet printing and spin coating can be applied when using quantum dots.

This allows them to be integrated quickly, easily, and at a low cost. Quantum dots are a new technology for emitting colorful light. These small lights are very promising because they are designed to emit highly specific colors very efficiently, paving the way for more vivid and realistic displays.

In the near future, there is a good chance that the screen of your cell phone will be made with quantum dots. So, that's it, folks! I hope you really enjoyed this video!

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