Perovskite-silicon tandem solar cell relying on silica nanospheres achieves 33.15% efficiency
Researchers in China have improved interface engineering in perovskite-silicon solar cells by using industrially textured silicon. The result is a highly efficienct tandem device that also showed remarkable stability.
Researchers in China have improved interface engineering in perovskite-silicon solar cells by using industrially textured silicon. The result is a highly efficienct tandem device that also showed remarkable stability.
A group of scientists at Zhejiang University in China has developed a perovskite-silicon tandem solar cell that utilizes textured silicon substrates to improve interface engineering between the top perovskite device and the silicon bottom cell.
The proposed architecture employs submicron contacts based on silica (SiOX) nanospheres to regulate silicon substrates that exhibit iceberg-like pyramids on the perovskite top cell, which represent a challenge for commercial production in standard photovoltaic manufacturing processes.
“Industrially textured silicon (ITS), featuring micron-sized pyramids, offers a more attractive and cost-effective solution,” the researchers pointed out. “These substrates can be produced directly within existing silicon cell manufacturing processes, ensuring scalability and compatibility with established industrial practices. Additionally, the industrially textured surface enhances light trapping, potentially improving the efficiency of tandem solar cells.”
The SiOX nanospheres were used to fill the valleys of silicon pyramids, which reportedly improves the coverage of the cell's self-assembled monolayers (SAMs) and enables a “more effective” perovskite deposition. In previous research, alumina oxide (Al₂O₃) nanoparticles or polymethyl methacrylate (PMMA) were used for this purpose. Compared to these two compounds, SiOX is claimed to have the ability to settle into the pyramid valleys of the textured silicon surface during the spin-coating process.
The silicon substrates were then coated with a SAM made of a phosphonic acid known as 2PACz.
The top perovskite cell was built with a substrate made on indium tin oxide (ITO) and the proposed SAM, a perovskite absorber, a tin(IV) oxide (SnO2) buffer layer, an electron transport layer made of buckminsterfullerene (C60), a transparent back contact made of indium zinc oxide (IZO), and a silver (Ag) metal contact.
Tested under standard illumination conditions, the 1 cm2 tandem cell achieved a power conversion efficiency of 33.15%, which the scientists described as the the highest efficiency ever reported to date for monolithic perovskite-silicon tandem solar cells utilizing ITS.
“Notably, we found that the buried interface of perovskites at bottom of pyramid valleys was strengthened in the tandems, demonstrating superior stability compared to tandems with submicron textured silicon (STS),” the academics emphasized, noting that the cell was also found to retain 91.7% of its initial efficiency after 1,000 h, with a STS tandem counterpart retaining only 78.4%.
The device configuration was presented in the study “Iceberg-like pyramids in industrially textured silicon enabled 33% efficient perovskite-silicon tandem solar cells,” published in nature communications.
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