One of the major road blocks to the design and development of new, more efficient solar cells may have been cleared. Researchers with the Lawrence Berkeley National Laboratory (Berkeley Lab) have developed the first ab initio method – meaning a theoretical model free of adjustable or empirical parameters – for characterizing the properties of “hot carriers” in semiconductors. Hot carriers are electrical charge carriers – electrons and holes – with significantly higher energy than charge carriers at thermal equilibrium. “Hot carrier thermalization is a major source of efficiency loss in solar cells, but because of the sub-picosecond time scale and complex physics involved, characterization of hot carriers has long been a challenge even for the simplest materials,” says Steven Louie, a theoretical physicist and senior faculty scientist with Berkeley Lab’s Materials Sciences Division (MSD). “Our work is the first ab initio calculation of the key quantities of interest for hot carriers – lifetime, which tells us how long it takes for hot carriers to lose energy, and the mean free path, which tells us how far the hot carriers can travel before losing their energy.” All previous theoretical methods for computing these values required empirical parameters extracted from transport or optical measurements of high
The post First Ab Initio Method for Characterizing Hot Carriers Could Hold the Key to Future Solar Cell Efficiencies has been published on Technology Org.
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