A team of researchers from Rice University, Houston, Texas, is developing a technology that helps use sunlight to power fuel cells.
According to the researchers, the technology involves the capture of solar energy dissipated as heat by what are called hot electrons. Hot electrons capture much of the energy in sunlight and get easily discharged, in the process converting the energy to heat.
The Rice University team claims to have managed to convert the energy given out by the hot electrons to split water molecules into hydrogen and oxygen. These gases are then used to power fuel cells.
In addition to improving the quality of solar module manufacturing the technology could also support the US initiative of reducing solar power costs.
The researchers have published details of their project in the American Chemical Society journal Nano Letters.
Lead researcher of the project and assistant professor at Rice University Isabell Thomann has stated: “Hot electrons have the potential to drive very useful chemical reactions, but they decay rapidly, and people have struggled to harness their energy.
“Most energy loss from the best photovoltaic solar panels of the day happens due to hot electrons, which cool within a few trillionths of a second and release their energy as wasted heat.”
The technology being developed by Thomann and team features three layers of materials. It has a thin sheet of shiny aluminum as the base. It is coated with transparent nickel-oxide. And above this layer ther is a scattered collection of plasmonic gold nanoparticles. These are puck-shaped disks about ten to 30 nanometers in diameter.
The aluminum attracts electron holes and the nickel oxide allows these to pass while also acting as an impervious barrier to the hot electrons, which stay on gold.
The researchers have found that by covering the sheet of material “with water gold nanoparticles act as catalysts for water splitting.
Currently, though, the researchers have not measured the quantum of hydrogen and oxygen released in the process. They have measured only the photocurrent available for splitting water.
Thomann says the “results warrant further study”.
Ajith Kumar S
editor@greentechlead.com