Researchers from the Institute for Electronic Science at Hokkaido University have designed a photoelectrode that is 11 times more efficient then current solar panels. They call it the “golden sandwich”.
A photoelectrode uses light to initiate chemical reactions and produce energy. This particular one is composed of a 30 nanometer thick Titanium Dioxide film coupled with gold nano-particles on one side and a 100 nanometer thick gold film on the other.
Nano particles are a growing sector of advanced materials science with recent implications for a lot of different industries ranging from energy to medicine and even meteorology.
This experimental photoelectrode has yet to reach commercial production but given it’s unrivaled conversion efficiency will certainly unleash some serious potential on to the expanding fields of solar power and sustainable energy when it’s finally released. The study was published in nature nanotechnology.
So how does it work? Well the gold nanoparticles demonstrate a feature called localized plasmon resistance which allow them to absorb a larger range of the eletromagnetic spectrum. In order to leverage this effect another layer of gold is included on the opposite side of the Titanium Dioxide layer that can actually reflect light back to the first layer of gold nanoparticles in order to maximize conversion efficiency.
“Our photoelectrode successfully created a new condition in which plasmon and visible light trapped in the titanium oxide layer strongly interact, allowing light with a broad range of wavelengths to be absorbed by gold nanoparticles,” says Hiroaki Misawa, lead author of the study report.
“The light energy conversion efficiency is 11 times higher than those without light-trapping functions.”
“Using very small amounts of material, this photoelectrode enables an efficient conversion of sunlight into renewable energy, further contributing to the realization of a sustainable society.”
Layering different compounds on top of one another to improve conductivity is an increasing trend in nanotechnology. For example, researchers have recently discovered that layering graphene with hexaazatrinaphthalene tricarboxylic acid (HATNA) increases the charge-recharge endurance of organic lithium ion batterys by 400-667%.
Similarly, painting a layer of perovskite on top of solar panels made of a compound called “CIGS” (copper-indium-gallum-selenium) increases conversion efficiency by 20% while painting perovskite over top of silicon panels will increase efficiency by 14%.
On the more quantum side of things molecular solar thermal energy storage could become the solar battery of the future by charging super-cool quantum liquid sandwiched between two plates of crystal silicon and quartz with electricity.
Photo credit: Misawa H. et al., Nature Nanotechnology, July 30, 2018