News Feature | February 23, 2022

Bright Ideas — Room Temperature Research For Time Crystals, Quantum Simulators, And Germans To Recycle Silicon From Solar Cells

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By Abby Proch, former editor


Recycled solar cell fragments are seeing new life as Passivated Emitter and Rear Cell (PERC) solar cells thanks to a recycling effort spearheaded by Fraunhofer Institute. In Germany, solar panels installed around 2010 will likely see the end of their lifespan around 2030, and German researchers are getting ahead of the mass disposal by preparing a pathway for recycling the nearly 150,000 tons of silicon it estimates is present in current photovoltaic systems.

The proposed process, which is back with government buy-in, would piece-by-piece deconstruct the system until only the silicon remains. The silicon would then be processed into monocrystalline or quasi-monocrystalline ingots and then into wafers. Viability remains a question, however, as Fraunhofer estimates the 100% recycled silicon carries a 19.7% conversion efficiency, just shy of the 22.2% efficient in PERC solar cells but still above that of the older modules.

A room temperature revelation by researchers at University of California – Riverside might mean time crystals could exist outside of a lab and be integrated into real-world applications. Historically, time crystals have been studied at temperatures very near absolutely zero, but with self-injection locking, researchers were able to maintain a stable laser optical frequency and temperature. "We hope that this photonic system can be utilized in compact and lightweight radiofrequency sources with superior stability as well as in precision timekeeping," explained engineer Hossein Taheri.

Also aiming to operate in ambient temperature, engineering professor Wei Bao is using a roughly $750,000 National Science Foundation grant to develop a quantum simulator that runs at room temperature. Bao, an assistant professor at the University of Nebraska – Lincoln, said he aims to make the study of quantum effects more accessible and affordable to other researchers. Bao didn’t divulge many details but said “his work seeks to synthesize novel optical materials, integrate them with photonic structures, demonstrate functional room-temperature quantum simulators and use them to study the rich, exotic materials properties that previously have been challenging to fully understand.”

In satcom news, CACI International has absorbed a $16.3 million SA Photonics contract to provide 40 optical communications terminals as links for satellite-to-satellite communication to the DARPA Blackjack program. In December 2021, CACI purchased SA Photonics, a California-based photonics company, for $275 million. The Blackjack program began in 2018 and is an experiment to demonstrate “military utility” within low earth orbit (LEO). One of the program’s goals is to use universal mass-produced sensors in the hopes of keeping costs below $2 million per payload, much lower than traditional military spacecraft.

And for fourth time, Heriot-Watt University has won the Queen’s Anniversary Prize in the United Kingdom, a biennial award that celebrates the best colleges and universities in their respective fields of study. Specifically for Heriot-Watt, it was their advancements in photonics — from “nanoscale of mobile phone circuitry to the macroscale of ship‐building” to optical fiber sensor applications. Heriot-Watt also recently announced its part in supporting the Quantum Encryption Science Satellite (QEYSSat) that, led by the Canadian Space Agency, will launch into low earth orbit (LEO) in 2024 to serve as a link for quantum communication across the Atlantic Ocean. For its part, Heriot-Watt will use a new “high-rate entangled photon source” to connect UK-based ground stations with QEYSSat.