An investigative group has presented a pioneering tandem solar cell, harnessing antimony selenide as its foundational material and coupling it with a larger bandgap hybrid perovskite material for its uppermost layer. Such a device has realized a power conversion efficiency rising above 20 percent. These findings underscore the substantial applicability of antimony selenide in the realm of bottom cell implementations.
Photovoltaic innovation captures solar energy and translates it into electric power. It is favored due to its supply of renewable and eco-friendly energy. Specialists persist in their quest to augment the power conversion efficiency of solar cells. Over 20 percent efficiency has been accomplished in standard single-junction solar cells. Surpassing the Shockley-Queisser threshold in such cells necessitates extensive financial outlay. Nevertheless, this threshold can be transcended in the manufacture of tandem solar cells. Through layering materials, tandem cells provide a boost in capturing energy from the sun.
Advancement of Antimony Selenide Tandem Solar Cells
The investigative team has striven to engineer tandem solar cells featuring the semiconductor antimony selenide. While previous studies on antimony selenide targeted its use in single-junction cells mostly, the team posited that its bandgap characteristics could render it an excellent option for tandem cell foundations.
“Antimony selenide stands out as a prospective choice for the fundamental substance in tandem solar cells. The scarcity of tandem cells employing it has led to a lack of focus on its potential uses. Our assembly of a high-efficiency dual cell using this material as the bottom component showcases its promise,” explained Tao Chen, a professor of Materials Science and Engineering at the University of Science and Technology of China. Tandem solar cells are superior in sunlight absorption compared to their single junction counterparts that utilize a single semiconductor layer. Consequently, they convert a elevated share of solar energy into electrical power, making them more efficient than single junction cells.
Illustration of an innovative tandem solar cell integrating antimony selenide with high-band-gap perovskite as the absorption materials of the bottom and top subcell, respectively. This device surpasses 20% power conversion efficiency through the optimization of the top cell’s transparent electrode and the bottom cell’s fabrication technique. Credit: Energy Materials and Devices, Tsinghua University Press
Improvements in Solar Cell Engineering
The group fabricated a tandem solar cell featuring a transparent perovskite/antimony selenide conductor electrode, fully optimized for spectral reception. They edited the transparency of the electrode layer atop the cell to attain an efficiency exceeding 17 percent. In tuning the antimony selenide foundational cell through the addition of a dual electron transport layer, they achieved a conversion efficiency standing at 7.58 percent.
Once they mechanically linked the upper and lower cells to form a four-terminal tandem solar cell, the power conversion efficiency exceeded 20.58 percent, outperforming the efficiencies of the autonomous subcells. The tandem cell shows outstanding durability with environmentally benign components. “This research paves the way for a novel tandem device architecture and positions antimony selenide as a future optimal absorbing material for bottom cell uses in tandem solar cells,” reported Chen.
Forward-looking, the team aims to progress towards a more collective two-terminal tandem solar cell and enhance its performance further. “The robust stability of antimony selenide allows for ease in developing a two-terminal tandem solar cell, suggesting potential success when coupled with various top cell materials types.”
The study collective includes Zhiyuan Cai, Huiling Cai, Yuehao Gu, Rongfeng Tang, Changfei Zhu, and Tao Chen of the University of Science and Technology of China, with Jia Sun and Paifeng Luo hailing from the Hefei University of Technology.
This study received financial aid from the National Key Research and Development Program of China; the National Natural Science Foundation of China; the School-Local Cooperation Industrial Innovation Guidance Fund Key Project at the Hefei University of Technology, China; the Wuhu Major Engineering Application Project, China; and the Collaborative Innovation Program of Hefei Science Center, CAS.
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