An illustration showing multiple plasmon-powered solar thermoelectric generators (STEG) connected in series. Credit: Namitha Deepak, IISER Pune
A thin film of gold nanoparticles boosts the sunlight-to-electricity conversion efficiency of a solar thermoelectric generator (STEG) to almost 9.6% at ambient conditions, generating enough voltage to run a low-power fan1.
Most solar cells only absorb sunlight at infrared wavelengths – the unabsorbed part is lost as heat. To fabricate a better light-harnessing device, scientists at the Indian Institute of Science Education and Research in Pune attached a thin film of gold nanoparticles to one side of a commercial STEG and exposed it separately to sunlight and artificial light.
The gold nanoparticle film efficiently absorbs and converts the sun’s visible and ultraviolet rays into heat and transfers it to the STEG. The device, cheaper than silicon-based solar cells, converts the heat to electricity.
Two connected STEGs powered a combination of a calculator and a timer, and three connected STEGs lit up 120 LEDs, which were used to create a pattern of ‘PLASMON’.
The researchers used the STEGs to run the electrical devices multiple times for several months without any drop in the output voltage. Under vacuum, the STEG's efficiency was 11.5%.
The team, led by Pramod Pillai, says this improved device could split water molecules and generate green hydrogen and make solar water heaters.
