Laser Solar Cells: New Designs for More Efficient Solar PV Power Generation

13 May 2016

Laser Solar Cell
Laser Solar Cell

Physicists from the Institute of Photonics and Optical Science (IPOS) at the University of Sydney have proposed an innovative mechanism of harvesting solar energy more efficiently at lower costs than traditional photovoltaic (PV) cells.

Widespread adoption of efficient photovoltaic solar power is hampered in part by the costs of PV cells. A novel way to reduce these costs is through luminescent solar concentrators (LSCs) which dramatically reduce the amount of PV material required to convert solar energy.

Physically, LSCs are made of large sheets of transparent polymers or glass, doped with carefully chosen luminophores (e.g. dyes or quantum dots) which absorb incident sunlight and become photo-excited; they then emit photons when they relax. These photons are then guided to the edges of the sheets where PV cells are optically coupled, vastly reducing the amount of PV material required.

Conventional LSCs however rely on spontaneous emission of photons at essentially random longer wavelengths, and thus their efficiency is limited by significant reabsorption losses due to the overlap of absorption and emission bands.

In their paper published in Optics Express, PhD student MD Rejvi Kaysir, together with supervisors Professor Simon Fleming and Honorary Professor Alexander Argyros, and collaborators, present details of a novel stimulated LSC (s-LSC) design; presenting an innovative solution to these losses by engineering the emission spectrum of the LSCs to be spectrally narrower by using a low cost seed laser.

"We have developed a model and correspondingly identified the important physical parameters for the realisation of the s-LSC system. Now, we are investigating the right luminophores for this system," - MD Rejvi Kaysir.

Injection of a small amount of laser light (the seed source) causes, through stimulated emission, reshaping of the emission spectrum, reducing spontaneous random emission. The beam is kept inside the s-LSC through mirrors, and targeted towards the PV cell, which only needs to be the size of the seed source. This retains the advantages of LSCs while reducing both the amount of PV material required and the energy losses from reabsorption.

Professor Fleming, co-author on the paper, added, "we hope this design will trigger new materials research on suitable luminophores; allowing the development and progression of s-LSCs as candidates for large-scale integrated PV systems that offer great promise for improved solar power generation. "This important discovery was a result of a collaboration by IPOS at The University of Sydney, and the University of New South Wales.

Contact: Gabriel Nguyen

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