High Efficiency Sn(S,Se) 2 /Crystalline Silicon Tandem Photovolatics

Close up view of a dark blue solar panel
Project Type
April 2016
Research Themes
A team of researchers is studying the properties of a new type of solar cell material that could make solar panels more efficient and cost-effective.

The proposed seed project is aimed at exploring the synthesis and properties of the Sn(S,Se)2 alloy system for possible application as the top absorber layer in a stacked, double-junction tandem solar cell based on a crystalline silicon bottom cell. This project addresses the need to increase the efficiency of commercial silicon-based photovoltaics to make renewable energy more cost-competitive with fossil fuels. Sn(S,Se)2 alloys, which have not previously been explored for this application, have potentially ideal optical properties for tandem silicon solar cells, are comprised of mostly earth abundant elements and have a layered crystal structure which may enable them to be grown directly on silicon without the generation of defects. 

This project will explore the synthesis of Sn(SexS1-x)2 thin films across the entire composition range (x), characterize the electrical and optical properties of the films as a function of composition and study the atomic level alloy distribution and defects using ultra-high resolution electron microscopy techniques. The seed project will produce foundational knowledge on the properties of Sn(S,Se)2 alloys which can then be used to secure additional funding to develop high efficiency tandem silicon solar cells based on this technology. Three faculty members (two senior and one junior) from Materials Science and Engineering with complementary expertise in materials synthesis, structural characterization and electrical testing of thin films will participate in the research and supervise undergraduate and graduate students on the project. 

Resulting Publications

  • Fox, J.J., Zhang, X., Balushi, Z.Y.A. et al. Van der Waals epitaxy and composition control of layered SnSxSe2−x alloy thin films. Journal of Materials Research 35, 1386–1396 (2020). https://doi.org/10.1557/jmr.2020.19


Nasim Alem

Norris B. McFarlane Faculty Career Development Associate Professor of Materials Science and Engineering, Materials Science and Engineering