Fabrication of semiconductor nanocrystals in Vietnam

With a few nanometers in size, quantum dots made by Vietnamese scientists have great potential for security and biological research.

Under ultraviolet light, it is clear that quantum dots emit different colors on the euro.The surrounding are the containers containing the corresponding color emission quantum dots produced by the Institute of Materials Science

Quantum dot is actually a semiconductor crystal with a few nanometers in diameter ( one nanometer is one billionth of a meter ). The same substance but different sized quantum dots will emit different colors under infrared or ultraviolet light.

Taking advantage of this nature, many countries around the world have used quantum dots to mark goods, vouchers or paper money to combat counterfeiting, injecting quantum dots into animal bodies to observe and photograph muscles. cells, cells . In addition, quantum dots also have the potential to be used to detect cancer, deliver drugs to cancer cells .

Realizing the benefits of quantum dots, five years ago, researchers at the Institute of Materials Science began studying these dots. This is a very daring study in the context that Vietnam does not have the technology of microelectronics and expensive machinery to manufacture quantum dots by physical methods as developed countries.

Photos of SiO2 spherical particles are produced by scientists from the Institute of Materials Science

Even so, the group has so far achieved many encouraging results. Specifically, the group created CdSe quantum dots (Cadimi selenide) of size 3.2-3.7nm and CdS (Cadimi sulfide) with sizes of 2.6-3.2 nm. According to Associate Professor Pham Thu Nga, a member of the group, to make these dots, they used chemical methods. This is a very powerful and inexpensive tool for making quantum dots of the desired size, very suitable for developing countries.

Not only that, the team also successfully created SiO2 crystal globules, also by chemical methods. With dimensions of several tens to several hundred nanometers, SiO2 is not a semiconductor crystal, so it is not as fluorescent as a quantum dot. It was made to carry quantum dots into the cell, clearly showing the cell image. It is easy to imagine crystal ball-like particles like balls and quantum dots like marble balls sticking around.

According to Dr. Nga, in order to apply for such purposes in Vietnam, it is necessary to produce quantum dots and crystal globes with large numbers. This is the team's future plan. The production of quantum dots and crystal spheres by chemical methods in Vietnam will help reduce the price much compared to the same products of foreign countries. It is known that 100ml quantum dots used to mark organism cells produced by US Quantum Dot Company cost $ 600.

These are containers of quantum dots CdSe and CdS made by experts from the Institute of Materials Science.

VND 500,000 sheet under ultraviolet light

Emory Medical School experts have succeeded in attaching quantum dots to antibodies that identify certain cancer cells.They then used these dots to identify cancer areas in mice.

Scientists at Carnegie Mellon University (USA) have injected quantum dots into animal bodies.These crystals circulate for hours and provide fluorescence signals for at least 8 months - the longest luminescence period of quantum dots in vivo.This technology helps to study animals for a long time.

Add some potential applications of quantum dots

Recently, chemists from the University of Vanderbilf (USA) accidentally discovered a way to make quantum dots emit white light. With this discovery, in the future quantum dots will be used to make light-emitting diodes (LEDs), replacing the current incandescent bulb. The US Department of Energy estimates that LED lighting will reduce 29% of lighting energy in the US by 2025, helping households save $ 125 million.

Quantum dot can also be a material for producing optical switches. A single quantum dot can act as a microscopic electronic unit, such as a transistor, to form the basis of nanoscale electronics. At a size of 1-6nm, billions of quantum dots can fit on one pin.

Minh Son