MicroLink’s ELO-based IMM wafers. Photo: MicroLink Devices.

MicroLink Devices has entered into an exclusive license agreement with the U.S. Department of Energy’s (DOE) National Renewable Energy Laboratory (NREL) to commercialize Inverted Metamorphic Multi-Junction (IMM) solar cell technology. The IMM solar cell architecture enables the manufacture of solar cells with very high efficiency as well as light weight, which are ideal for powering satellites and solar aircraft.

According to MicroLink Devices, the most efficient solar cells are multi-junction, which means that they use multiple light-absorbing layers to convert different wavelength ranges of the solar spectrum into electricity. Multi-junction solar cells based on germanium substrates have historically been used exclusively in very high-performance satellite applications. The IMM design is a new approach to further improve solar cell efficiency by integrating an optimum combination of three or more compound semiconductor materials. MicroLink Devices has demonstrated an efficiency of 32.3 percent under 1-sun AM0 using an IMM design.

IMM solar cells are synergistic with MicroLink Devices’ proprietary Epitaxial Lift-Off (ELO) technology, which has been under development at the company for the past 10 years. Using the ELO process, MicroLink is able to peel off thin layers of active solar cell material, which enables the fabrication of solar cells with exceptional light weight and specific powers greater than 3,000 W/kg.  The substrate can also be used multiple times to lower manufacturing costs, the company stated.

MicroLink’s ELO technology was sponsored by numerous U.S. agencies including NASA, the Defense Advanced Research Projects Agency (DARPA), the Air Force Research Laboratory (AFRL), the Office of Naval Research, and others.

Microlink Devices previously announced a production contract to provide ELO multi-junction solar sheets to Airbus Defense and Space for use on the Zephyr S HALE platform — a new class of Unmanned Air Vehicle (UAV) that operates as a High-Altitude Pseudo-Satellite (HAPS).