- Researches found a new material that could make solar cells non-toxic and inexpensive.
- The new material is built by combining the atoms of copper, selenium, and titanium into a unique crystal structure.
Solar cells, often called photovoltaic cells, provide reliable and economical way of powering equipment which would otherwise require cumbersome and expensive fuel sources. The United Kingdom is strongly focusing on green energy, especially solar cells that can contribute to lower carbon dioxide emissions.
Over the past couple of decades, solar cells have developed a lot, thanks to advances in material science. Researchers all over the world are continuously putting a lot of effort to find new ways to increase their efficiency without adding cost or toxicity.
Recently, a team of researchers at Michigan Engineering found a new material that could make next-generation solar cells non-toxic, more efficient, and about 10 times cheaper than existing ones.
What’s Wrong With Exiting Solar Cells?
The conventional crystalline silicon solar cell can only produce a maximum open-circuit voltage of 0.6 volts, which is not enough to fulfill the optimal requirement of all households. Moreover, they are too bulky and take a large amount of energy to manufacture and install.
Nowadays, gallium arsenide is being used as an alternative to silicon. The large absorption coefficient of gallium arsenide, coupled with the ability to configure their band gap via chemical substitution, enables solar cells to yield up to 40 percent efficiency. Also, gallium arsenide cells are less bulkier and thinner than silicon-based solar cells.
However, there is one big problem: gallium is a very rare material, rarer than gold. The Earth’s crust doesn’t contain enough gallium to produce all the solar cells we are going to need in the future. Furthermore, arsenic is toxic in nature. It presents numerous environmental challenges and can cause cancer, skin changes and other heath problems.
The New Material
Researchers have built a new material by combining the atoms of copper, selenium, and titanium into a unique crystal structure. It can absorb light efficiently, and above all, these elements are non-toxic and way more cheaper than gallium arsenide.
Basically, they took atoms of each element and arranged them into a lattice. This work is built on an existing material that consists of 2 atoms of copper and indium (two from each), and 4 atoms of selenium.
However, Indium is quite expensive and toxic. The molecule with 8 atoms leaves a large amount of gaps in the crystal structure, which causes defects. Therefore, they replaced indium atoms with 1 atom of titanium and 2 additional atoms of copper. The resulting lattice has smaller gaps and fewer defects.
Producing a thin sheet of gallium arsenide involves a costly process known as molecular beam epitaxy. On the other hand, this new material could be processed by an inexpensive technique referred as power and pulse laser deposition. This drastically reduces the cost of production.
Compared to gallium arsenide, the new material can be made into thinner sheet, making finished products even lighter and easier to install. Considering all factors, researchers estimate that the final product would be approximately 10 times cheaper than gallium arsenide solar cell.
There is still a lot of work to do: the first thing is to alter the electronic configuration of molecules to make it more appropriate for solar energy use. It would take more than 3 years to release a working prototype.
Researchers believe that this technology could help solar energy to reach its potential by making it easy to install unobtrusive, lightweight solar cells into everyday objects like cars, clothing, building, and even in communication satellites.