No rare elements needed in novel solar-cell semiconductor zinc tin nitride
Bandgap is tuned by introducing disorder into the crystal lattice.
A team of researchers from diverse places -- University of Liverpool (Liverpool, England), the University of Buffalo (Buffalo, NY), Binghamton University (Binghamton, NY), University College London (London, England), and Western Michigan University (Kalamazoo, MI) -- has demonstrated a new semiconductor material made from abundant elements which can be tuned for use in solar cells, eliminating the need to use rare elements.1
The semiconductor, zinc tin nitride (ZnSnN2) has a bandgap once thought to be too large for use in photovoltaic cells; however, the researchers found that, by changing the fabrication conditions and thus introducing disorder at the atomic level, the semiconductor's bandgap could be tuned anywhere between 1 and 2 eV -- suitable for use in solar cells.
"Such tunability is typically achieved in other material systems by alloying, or blending in other elements, to obtain the desired result," says Tim Veal, a University of Liverpool researcher. "However, this is not necessary with ZnSnN2, given the recent discovery."
1. Tim D. Veal et al., Advanced Energy Materials (2015); doi: 10.1002/aenm.201501462