A new world record in solar cell efficiency of 44 percent has been set by the Energy Department’s National Renewable Energy Laboratory (NREL) in partnership with Solar Junction.
This new record which was achieved by improving an already existing multi-junction PV cell.
Last year, researchers at NREL’s III-V Multijunction Photovoltaics Group already set a record in efficiency last year with their SJ3 cells, which were verified as being able to convert 43.5 percent of sunlight into electricity at 415 suns.
These newest solar cells are a new iteration of previously successful multi-junction PV cells, and are combined with low-cost concentrating lenses to increase the intensity of sunlight hitting the cells. This has produced the record-breaking efficiency of 44 percent at 947 suns.
An operator inspects a photolithography tool used to manufacture high-efficiency Solar Junction concentrator solar cells. NREL's pioneering multijunction work led to the Solar Junction SJ3 solar cell with tunable bandgaps, lattice-matched architecture, and ultra-concentrated tunnel junctions. Credit: Daniel Derkacs/Solar Junction
The team accomplished this feat by finding a way around the band gap, which determines how a semiconductor material absorbs photons, and how a solar cell made of that material can efficiently extract energy from these protons.
“The ideal band gaps for a solar cell are determined by the solar spectrum,” said Daniel Friedman, manager of the NREL III-V Multijunction Photovoltaics Group.
“There’s no way around that.”
But the team succeeded in bending the rules of the solar spectrum, which led them to win the coveted R&D 100 award from R&D Magazine for their record-breaking multijunction solar cell, making it NREL’s third R&D 100 award for advances in ultra-high efficiency multijunction cells.
The team’s next goal is to tweak their design to raise the efficiency to 50 percent, setting another milestone in solar power if the researchers can achieve it.