What does the title “Researcher” mean to you? A scientist? An inventor? A creator? No! A researcher is a man disappointed in one particular aspect of his life, wants to make it better for himself, knows what others have searched, and then he re-searches new and more simple or more complex solutions to the same old problem.
In our case, the old problem is how to capture nature’s energy, hence the solar powered race for invisible gold.
Now, let’s get to the point: Penn State researchers have found a cheaper method of producing hydrogen from water by the same old effect of electrolysis aided by the Sun’s rays. They do not use classic solar cells, because these are expensive, but made a nanotechnology-based solar cell, called photoelectrochemical diode, that is simplistically said on the bottom of the water holding recipe. The photoelectrochemical diode is made out of two layers, placed on the two faces of it:
Layer 1: Titanium dioxide + iron, placed in direct sunlight, to absorb the ultraviolet spectrum (between 300 and 400 nanometers wavelength), because titanium dioxide is known for its sensitivity to ultraviolet light, and there’s plenty of them recently. Iron has been added to make the titanium dioxide resistant to photo corrosion, this way making it transparent to the visible light spectrum.
Layer 2: Titanium nanotube arrays, that absorbs the rest of the light spectrum, the visible one (400 to 885 nanometers wavelength) passing through the first layer. In such a combination, the researchers made a fully spectrum absorbing solar cell.
This description of the solar cell is a simplistic one, of course, and ScienceDaily covers a little more details on the actual scientific and physical phenomena happening there, but their explanations are a little harder to understand at first glance.
This photoelectrochemical diode produces a small quantity of electricity, approximately 0.25 milliampere per centimeter square, at a photoconversion efficiency of 0.30 percent. That’s a small number, but the researchers say it can easily be brought up to 5 to 10 percent efficiency. The electric current produced in this way electrolyzes the water and splits it into hydrogen and oxygen. Hydrogen is captured and used for whatever purpose (fuel cell, burning, etc).
In the end of the article, let’s not forget the sponsor of this experiment: US DOE (US Departament Of Energy). They’re interested.