It’s not the absorbing of photons that matters most, it’s the emitting of them. That counterintuitive bit of wisdom about boosting photovoltaic cell efficiency is at the heart of work at Lawrence Berkeley National Laboratory (Berkeley Lab) that has led to record-breaking solar cell performances.

According to the lab, the most efficient solar cells on the market today are made from monocrystalline silicon wafers that operate at about 23% efficiency – that is, they convert about 23% of the energy hitting the cell into electricity. But based on work by the Berkeley researchers, the private company Alta Devices – founded by lead researcher Eli Yablonovitch – was able “to fabricate solar cells from gallium arsenide that have achieved a record conversion efficiency of 28.4% ,” the lab said. Keep reading →