“Golden Sandwich” Photoelectrode Harvests 85% Of Sunlight | CleanTechnica
The breakthrough from Hokkaido University hints at renewable energy production that is 11 times more efficient than current systems. Of course, we have no idea what commercial versions of the technology might cost (if 11 times more than current systems, it’s a net-zero benefit), but just imagine getting 11 times as much zero-emissions energy from a photoelectrode. The implications are staggering.
So what’s the secret sauce for making a golden sandwich? A titanium dioxide film just 30 nanometers thick with a 100 nanometer thick gold film on one side and gold nano-particles on the other. When sunlight strikes the nanoparticle side, the gold film below acts as a mirror trapping the light in the cavity between the two gold layers. That helps the nano-particles to absorb more of the available light, which is critical to the surprisingly high energy conversion factor.