The use of sunlight as an energy source is achieved in a number of ways, from conversion to electricity via photovoltaic (PV) panels, concentrated heat to drive steam turbines, and even hydrogen generation via artificial photosynthesis. Unfortunately, much of the light energy in PV and photosynthesis systems is lost as heat due to the thermodynamic inefficiencies inherent in the process of converting the incoming energy from one form to another. Now scientists working at the University of Bayreuth claim to have created a super-efficient light-energy transport conduit that exhibits almost zero loss, and shows promise as the missing link in the sunlight to energy conversion process.
Using specifically-generated nanofibers at its core, this is reported to be the very first time a directed energy transport system has been exhibited that effectively moves intact light energy over a distance of several micrometers, and at room temperature. And, according to the researchers, the transference of energy from block to block in the nanofibers is only adequately explained at the quantum level with coherence effects driving the energy along the individual fibers.
Quantum coherence is the phenomenon where subatomic waves are closely interlinked via shared electromagnetic fields. As they travel in phase together, these quantum coherent waves start to act as one very large synchronous wave propagating across a medium. In the case of the University of Bayreuth device, these coherent waves of energy travel across the molecular building blocks from which the nanofibers are made, passing from block to block and moving as one continuous energy wave would in unbound free space.
It is this effect that the scientists say is driving the super-low energy loss capabilities of their device, and have confirmed this observation using a variety of microscopy techniques to visualize the conveyance of excitation energy along the nanofibers.
The nanofibers themselves are specifically-prepared supramolecular strands, manufactured from a chemically bespoke combination of carbonyl-bridged (molecularly connected) triarylamine (an organic compound) combined with three naphthalimide bithiophene chromophores (copolymer molecules that absorb and reflect specific wavelengths of light). When brought together under particular conditions, these elements spontaneously self-assemble into 4 micrometer long, 0.005 micrometer diameter nanofibers made up of more than 10,000 identical chemical building blocks.
"These highly promising nanostructures demonstrate that carefully tailoring materials for the efficient transport of light energy is an emerging research area," said Dr. Richard Hildner, an experimental physicist at the University of Bayreuth.
The results of this research were recently published in the journal Nature.
Source: University of Bayreuth