New nanomaterials: The future of solar energy

In the race to make solar cells cheaper and more efficient, many researchers and companies are expecting a nanoscale structure of one-billionth of a meter. Using nanotechnology, scientists can experiment and control how the production, collection, transport and storage of free electron radicals play an important role in the transition from sunlight to electricity. power.

Two methods of operating solar cells using nanotechnology promise high success. One method is to use thin films from nano-metal oxide molecules, such as titanium dioxide, combined with other elements such as nitrogen. Another method uses quantum nanocrystals that are able to absorb strong light. Micro-semiconductors push electrons into a metal oxide film, or "light," that enhances the solar transition. Both methods promote the absorption of light by metal oxide materials.

Jin Zhang - chemistry lecturer at the University of California, Santa Cruz (Photo: T. Stephens)

According to Jin Zhang, a professor of chemistry at the University of California, Santa Cruz, combining these two methods will create better solar battery materials than either . Zhang, the leader of the research team, including scientists from California, Mexico and China, created a thin film of nitrogen coated and lit up with quantum spots.

'We have discovered a new method that could be very useful to improve the transition of solar cells based on nanomaterials. First, we think that the result of the two separate methods will be the best and can be combined will not succeed, but surprisingly, this new material is much better. '

The study of the group is presented in the journal Physical Chemistry in a report published online on January 4. The main author of the report is Tzarara Lopez-Luke, a graduate student visiting the lab of Zheng, currently located at Instituto de Investigaciones Metalurgicas, Mexico.

Zhang's team determined the properties of nano-plastic materials with a variety of tools such as atomic force microscopes, electron conversion microscopes, Raman spectroscopy methods and other techniques that use electrochemical. The group created films that range in thickness from 150 to 1100 nanometers, with titanium dioxide molecules having an average size of 100 nanometers. The group also dipped titanium dioxide mesh into nitrogen atoms; For this film, they use chemical bonds to quantum spots made from cadmium selenide to light up.

This new hybrid material has many benefits. Nitrogen makes these materials absorb many types of light energy including energy from the visible region of the electromagnetic spectrum. Quantum dots also enhance the absorption of visible light, enhance the electric current and the energy metabolism of materials. When compared to other materials that only dip nitrogen or are only added to cadmium selenide quantum spots, the nanoparticles combine both to show a higher performance, according to the quantum conversion efficiency formula. incident light into electricity (IPCE). The IPCE index of nano plastic is nearly 3 times higher than the total IPCE index of two separate materials.

Zhang explained: 'We think that charge easily moves through this material. That can only happen if the quantum point is bright and nitrogen is active at the same time. '

Nanocomposite materials are not only used to improve solar batteries, but can also be useful in energy technology. One of Zhang's long-term goals is to combine a high-performance solar battery with a high-tech electrochemical battery. Theoretically, such a device could use the energy produced from sunlight to split water and produce hydrogen energy. Nanocomposite can also be used to convert CO2 into hydrocarbon energy such as methane.

The new method of making solar battery materials promises a new research direction for Zhang's lab for years to come.'The work has only just begun and there are many steps we have to make. We have 3 types of materials to conduct research until we reach the desired energy level. '

In fact, the team is testing the multiplication of materials so that when the sun shines on, freely generated electrons can easily move from one energy level to another or between different materials and eventually converted into electricity effectively. Zhang said: 'The method we are working on is actually increasing the energy level of the nanocomposite so that electrons can operate more efficiently. If our test is successful, we are using this method very effectively. '