The world record for energy efficiency of photovoltaic cells has been broken again. The National Renewable Energy Laboratory (NREL), together with their partner Solar Junction, reported the incredible 44% efficiency achieved through improvement of the already existing multi-junction PV cells.
The layered semiconductors used in the cells were previously optimized to capture various wavelengths of light. Now these are combined with low-cost concentrating lenses, allowing multiplication of the intensity of the incoming solar energy that hits the cells.
It was only last year, when the record was broken by a team at NREL and Solar Junction with their SJ3 cells, designed for utility-scale concentrated solar photovoltaic projects. The estimated conversion rate of these cells was 43.5% at 415 suns. It is not long later that the guys managed to raise the bar to 44% at 947 suns with their latest invention.
The ultimate aim of NREL is to reach the 50% efficiency benchmark in the very near future.
Daniel Friedman, manager of the NREL III-V Multijunction Photovoltaics Group points out that the partnership with Solar Junction was what turned the lab invention into a huge commercial success.