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Phoenix666 [soylentnews.org] writes:

Researchers have found a way to quintuple the number of electrons that can be harvested from light [futurity.org]:

In traditional light-harvesting methods, energy from one photon only excites one electron or none depending on the absorber’s energy gap, transferring just a small portion of light energy into electricity. The remaining energy is lost as heat. But in the paper in Science Advances [doi.org], Wu, associate professor Xiaodong Xu, and colleagues describe one promising approach to coax photons into stimulating multiple electrons.
...
Xu and Wu discovered that when the graphene layer’s lattice is aligned with the layers of boron-nitride, a type of “superlattice” is created with properties allowing efficient optoelectronics that researchers had sought. These properties rely on quantum mechanics, the occasionally baffling rules that govern interactions between all known particles of matter. Wu and Xu detected unique quantum regions within the superlattice known as Van Hove singularities.

“These are regions of huge electron density of states, and they were not accessed in either the graphene or boron-nitride alone,” says Wu. “We only created these high electron density regions in an accessible way when both layers were aligned together.”

When Xu and Wu directed energetic photons toward the superlattice, they discovered that those Van Hove singularities were sites where one energized photon could transfer its energy to multiple electrons that are subsequently collected by electrodes—not just one electron or none with the remaining energy lost as heat. By a conservative estimate, Xu and Wu report that within this superlattice one photon could “kick” as many as five electrons to flow as current.

The next step is to organize the excited electrons into current.

From the original study, "Multiple hot-carrier collection in photo-excited graphene Moiré superlattices [sciencemag.org]."

Original Submission