Scientists in USA have created the record for highest efficiency in solar hydrogen production via a photoelectrochemical (PEC) water-splitting process.
The new solar-to-hydrogen (STH) efficiency record is 16.2 percent, topping a reported14 percent efficiency in 2015 by an international team made up of researchers from Germany.
The record-setting PEC cell represents a significant change from the concept device Turner developed at NREL in the 1990s.
Both the old and new PEC processes employ stacks of light-absorbing tandem semiconductors that are immersed in an acid/water solution (electrolyte) where the water-splitting reaction occurs to form hydrogen and oxygen gases.
But unlike the original device made of gallium indium phosphide (GaInP2) grown on top of gallium arsenide (GaAs), the new PEC cell is grown upside-down, from top to bottom, resulting in a so-called inverted metamorphic multijunction (IMM) device.
