Tandem solar cells represent a significant advancement in photovoltaic technologies. A team of researchers recently demonstrated, for the first time, a tandem solar cell concept using antimony selenide as the bottom cell material and a wide bandgap organic-inorganic hybrid material as the top cell.
The innovation has achieved a power conversion efficiency of more than 20%. This study highlights the potential of antimony selenide for lower cell applications.
Photovoltaic technology and conversion efficiency
Photovoltaic technology, which harnesses sunlight to convert it into electricity, is popular for its clean and renewable nature. Scientists are constantly working to improve the power conversion efficiency of solar cells. Conventional single-junction solar cells have already achieved conversion efficiencies of over 20%. To exceed the Shockley-Queisser limit in these cells, however, much higher costs would be necessary.
The Shockley-Queisser limit of single junction solar cells can be overcome through the fabrication of tandem solar cells. By stacking solar cell materials on top of each other, researchers are able to achieve greater energy efficiency.
Antimony selenide in tandem solar cells
The research team worked to create tandem solar cells using a semiconductor called antimony selenide. Previous research on this material has mainly focused on applications in single junction solar cells. The team knew that, from a bandgap perspective, this semiconductor could prove to be a suitable lower cell material for tandem solar cells.
“ Antimony selenide is a lower cell material suitable for tandem solar cells. However, due to the rarity of reported tandem solar cells using this material as the bottom cell, little attention has been paid to its application. We assembled a tandem solar cell with high conversion efficiency using it as a bottom cell to demonstrate the potential of this material said Tao Chen, professor of materials science and engineering at the University of Science and Technology of China.
Manufacturing and optimization of tandem solar cells
The team fabricated perovskite/antimony selenide tandem solar cells with a transparent conductive electrode for optimized spectral response. They were able to adjust the thickness of the transparent electrode layer of the upper cell to achieve a high efficiency of more than 17%. They optimized the lower antimony selenide cell by introducing a double electron transport layer and achieved a power conversion efficiency of 7.58%.
By mechanically joining the upper and lower cells to create the four-terminal tandem solar cell, the power conversion efficiency exceeded 20.58%, which is higher than that of independent sub-cells. Their tandem solar cell features excellent stability with non-toxic compositional elements. “ This work provides a new tandem device structure and demonstrates that antimony selenide is a promising absorber material for lower cell applications in tandem solar cells. ” Chen added.
Future prospects
In the future, the team hopes to work toward a more integrated two-terminal tandem solar cell and further improve the device’s performance. “ The high stability of antimony selenide provides great convenience for the preparation of two-terminal tandem solar cells, which means that it could perform well when combined with several different types of top cell materials. »
Article: “Sb2Se3 as a bottom cell material for efficient perovskite/Sb2Se3 tandem solar cells” – DOI: 10.26599/EMD.2024.9370027
