Insights into efficient solar cells from earth-abundant elements

In recent years, zinc phosphide has garnered increasing interest as a semiconductor for solar cells, both due to its functional properties and to the global abundance of zinc and phosphorous. Now, the LMSC has published a paper in the journal Solar Energy Materials and Solar Cells describing a first solar cell device made from zinc oxide in a heterojunction with indium phosphide. Their device demonstrates an efficiency above 4%; a result that, according to Fontcuberta i Morral, supports the potential of zinc phosphide as a “material of the future.”

In their study, the LMSC investigated the dominant recombination mechanisms within the film using different techniques to identify key factors underpinning its efficiency. In particular, they found that reduced carrier collection at the front of zinc phosphide is responsible for the reduced collection of high-energy photons. This insight allowed the researchers to propose improved design rules for efficient, next-generation zinc phosphide-based heterojunction solar cells.

These results are the fruit of Fontcuberta i Morral’s Swiss National Science Foundation Consolidator Grant project, launched in 2015, and the start of the Horizon Europa Pathfinder project SOLARUP, highlighting the importance of collaborations with Europe for innovation.