One-Step Process to Make Black Silicon
It makes sense that one way to improve the power output of a solar panel is to increase the amount of light that hits its active elements. One means to achieve this is to employ black silicon, which reflects almost no light. Researchers at Rice University have recently found a way to produce black silicon in a single step, which could drastically improve manufacturing.
The key to black silicon is its surface, which is covered with spikes or pores that are smaller than the wavelengths of light. This results in a black surface that will absorb light at almost any angle, which is an improvement over some coatings that are only anti-reflective at certain angles and for certain wavelengths. The researchers found that silicon could have these features etched onto its surface using a mix of copper nitrate, phosphorous acid, hydrogen fluoride, and water. The acid and copper nitrate produce copper nanoparticles, which oxidize the silicon surface, and that allows the hydrogen fluoride to burn nanopores into the silicon.
The result was a layer of black silicon that let through 99% of light, to the active silicon layer. Now the researchers are looking for a coating to protect the black silicon and ways to shorten the eight-hour process involved. Still, by making this a one-step process, black silicon could become much more practical to use than ever before.
Source: Rice University