Refractory InGaN Solar Cells Sustain Stable Operation at Ultra High Temperatures

Achievement date: 
2017
Outcome/accomplishment: 

In collaboration with Photonitride Devices, Inc., scientists from Quantum Energy and Sustainable Solar Technologies (QESST) have produced a new class of solar cells with the ability to produce power at extreme temperatures. By modifying the structure of a blue light-emitting diode (LED), indium gallium nitride (InGaN) solar cells – known as “refractory solar cells”  – have been enabled that possess the ability to sustain operation at record-breaking temperatures of 600 degrees Celsius (C). QESST is an NSF-funded Engineering Research Center (ERC) co-funded by the Department of Energy (DOE) and headquartered at Arizona State University (ASU).

Impact/benefits: 

Refractory solar cells can be used as thermal topping cells on the receivers of concentrating solar power (CSP) to concentrating photovoltaic (CPV) power plants. The new solar cells allow direct conversion of electricity from sunlight, a more efficient process than the use of light to heat to mechanical energy to electricity. Additionally, as thermal topping cells, the refractory solar cells allow all inefficiencies to become heat, maximizing the available energy.

Refractory solar cells also expand the range of environments in which photovoltaic (PV) technology can be used. In addition to applications in CSP-CPV hybrid plants, these cells open new applications in areas such as power beaming for wireless recharging of electric unmanned aerial vehicles (UAVs); high temperature cells for space probes to Venus and Mercury; and deployment in nuclear-photovoltaic hybrids.

Explanation/Background: 

Gallium nitride (GaN) and related InGaN materials have enabled the LED lighting revolution our society is currently experiencing. The industry surrounding these semiconductor technologies has grown exponentially and QESST’s work proves that the technology can also be used as an enabling material for solar cells.

The new refractory solar cells consist of blue-LED technology enabled by InGaN quantum wells in a GaN diode. The GaN and InGaN materials are naturally stable at high temperatures, both chemically and electrically. This is due to the strength of the group III-N atomic bonds and the wide band gap of the material. The end result is that these materials are capable of creating PV devices operable at temperatures far hotter than any other available today.

The QESST team’s results and corresponding analysis were presented as a talk at the 43rd IEEE Photovoltaic Specialist Conference in June 2016 and submitted for publication in the Journal of Photovoltaics.