Researchers from Stanford University have recently displayed a manner in which nanotechnology could be utilized to make crystalline silicon thin-film solar cells.

They can capture solar energy more efficiently and can be produced at a much cheaper cost.

Crystalline Silicon Thin-Film Solar Cells

The researchers noted that the new technique can lower the production of solar energy cost globally. The research team is comprised of three members, which include lead researcher Dr. Shrestha Basu Mallick, as well as her advisors Dr. Peter Peumans and Dr. Mark Brongersma.

The research team showed that a solar cell with a thin-film crystalline silicon, having a two-dimensional nanostructure, could produce thrice as much photocurrent as a nonstructured cell, which has a similar thickness with the help of electrical simulations and optical modeling.

Such a process can take place because the nanostructured surface can trap the light that comes in more effectively and causes it to stay for a longer time inside the silicon material. There is a greater chance of the light getting absorbed if it spends more time within the solar cell.

"Light absorption in crystalline silicon solar cells can be significantly enhanced by nanostructuring and this reduces the thickness of silicon required," said Basu Mallick. "This is important because it helps countries be competitive against imported cells and paves the way for new solar applications such as flexible or transparent cells."

The findings unveiled an easy process to improve the efficiency of silicon solar cells. The researchers have published their study in the journal Optics Express.

Cost-Effective Method

“Crystalline silicon is an attractive photovoltaic material because of its natural abundance, accumulated materials and process knowledge, and its appropriate band gap,” read a paragraph from a 2010 paper.

Thin crystalline silicon films can be utilized not to only reduce costs but also the amount of material required. They enable material with lengths of shorter carrier diffusion to be utilized.

The indirect band gap of silicon, however, needs that an approach based on light trapping will be utilized to make the optical absorption optimal.

“Here, a photonic crystal based approach is used to maximize solar light harvesting in a 400 nm-thick silicon layer by tuning the coupling strength of incident radiation to quasi-guided modes over a broad spectral range,” the abstract further stated.

The structure contains a PC with double layers, with the top layers containing holes that have a radius, which is smaller in comparison to the holes present in the bottom layer.