Scientist Create 68.9%- efficient PV Cell for Laser power Transmission

• Along with the classic applications for solar cells on roofings and also open spaces, photovoltaic or pv tools can also be used with laser light for reliable power transmission.
• Researchers at Germany's Fraunhofer ISE case to have achieved a 68.9% conversion effectiveness rate for a III-V solar cell that can be used in laser power transmissions systems.

At the lately held 48th IEEE Photovoltaic Specialists Conference, scientists from the Fraunhofer Institute for Solar Energy Systems ISE presented their success of a record conversion efficiency of 68.9% for a photovoltaic cell under monochromatic laser light.

The scientists at Fraunhofer ISE claimed the success, describing that it was enabled with an unique thin film technology in which the solar cell layers were first expanded on a gallium arsenide substratum which was after that ultimately removed. A conductive, highly reflective mirror was put on the back surface area of the remaining semiconductor structure, which was only a few micrometers thick.

This was their process: Photovoltaic cells convert light into electrical power. The incoming light is absorbed in a cell structure, constructed from gallium arsenide semiconductor product, as an example. The taken in light sets positive and adverse costs totally free, which remain in turn conducted to the front and also back cell contacts, creating power. This "photovoltaic impact" is particularly efficient when the energy of the event light lies a little above the so-called bandgap energy intrinsic to the semiconductor material. Hence, extremely high efficiencies are in theory feasible when a single laser as source of light is matched with a suitable semiconductor compound material.

In this new form of energy transfer, called power by light, the laser energy is delivered either with the air or using a fiber optics to a photovoltaic cell whose properties match the power as well as the wavelength of the single laser light. Contrasted to traditional power transmission using copper cords, power by light systems are particularly beneficial for applications which require a galvanically separated power supply, lightning or explosion security, electromagnetic compatibility, or completely wireless power transmission, for instance.

" This thin film technique has two unique benefits for the effectiveness," discusses the physicist Dr. Henning Helmers, head of the Fraunhofer ISE research study team. "Firstly, photons are trapped in the cell and also the absorption is made best use of for photon energies near to the band space, which concurrently decreases thermalization and transmission losses, making the cell a lot more reliable. Second of all, the photons in addition produced internally by radiative recombination become trapped as well as properly reused. This extends the efficient carrier lifetime, thus furthermore boosting the voltage."

The study group checked out thin film photovoltaic cells with back-surface reflectors made from gold as well as an optically optimized combination of ceramic and also silver, with the latter revealing the most effective outcomes. An n-GaAs/p-AlGaAs heterostructure was established as absorber, which shows particularly reduced charge provider losses as a result of recombination.

"This is a remarkable outcome that reveals the possibility of photovoltaics for commercial applications past solar power generation," says a happy Prof. Andreas Bett, institute director of Fraunhofer ISE, Germany. Optical power transmission has manifold applications. Examples are the architectural monitoring of wind turbines; the surveillance of high-voltage lines, fuel sensors in airplane tanks, or passive optical networks; the optical supply of implants from outside the body; and so on