Producing solar energy from ... water

A scientific experiment can change the entire energy industry in the future.

New method to collect solar energy from water

Scientists at Ric University (USA) have found an effective way to collect solar energy by separating water molecules. This technology is based on the configuration of gold nanoparticles activated by light; These nanoparticles capture sunlight and convert solar energy into electrons in a state of highly excited, often called 'hot electrons'.

Isabell Thomann and colleagues.

Isabell Thomann, the lead researcher, said: 'Hot electrons are capable of producing very useful chemical reactions, but their energy is rapidly decayed so their energy control is very difficult. towel. For example, the main cause of energy loss in solar photovoltaic panels today is because hot electrons cool down in just a few trillionths of a second, causing their energy to be released. '

Therefore, the capture of these high-energy electrons before it cools can help solar energy providers to significantly improve the efficiency of converting solar energy into electrical energy.

In nanoparticles activated by light made by Thomann's team, light is collected and converted into plasmon, ie the vibrations of electrons move like a liquid across the metal surface of the particle. nano.Plasmon is a high-energy state with a short lifespan but scientists at Rice and elsewhere in the world have found a way to collect plasmon energy to convert it into useful electricity or photovoltaic. Plasmonic nanoparticles are also a promising device for controlling the energy of hot electrons.

Model of experiment using water separation technology to produce solar energy.

Thomann's team created a system that uses energy from hot electrons to separate water molecules into oxygen and hydrogen. This is an important result because Oxygen and Hydro are the basic materials of fuel cells, which means that electrochemical devices help create clean and efficient power sources. In order to use hot electrons, the team must first find ways to separate them from the 'electron holes' , ie the low energy states that they have left when they receive the stimulating energy source. One reason that hot electrons have a short lifespan is that they tend to release the newly received energy to return to a low energy state.

Sketch pictures when putting the experiment on an industrial scale.

The only way to prevent this trend is to create a system that can quickly separate hot electrons from electron holes. Typically, scientists will push hot electrons through an energy barrier that acts as a one-way valve. According to Thomann, this method has many ineffective points but is still concerned by scientists because it applies a proven technology called Schottky fence . Her team, instead of pushing away the electrons, creates a system to push the electron holes away. This system acts like a sieve or diaphragm: the electron holes can pass through it but the electrons are not hot, and therefore they are maintained on the surface of plasmon nanoparticles.

Thomann said: 'When using hot water electrolysis technology to create solar energy, we found that the photoelectric current has the same efficiency as other more complex systems and uses more expensive components. . We are confident that we can optimize this system to significantly improve current results ".