Longi sets new world record with 35.5%-efficient perovskite-silicon tandem cell

Longi has announced a power conversion efficiency of 35.5% for a two-terminal crystalline silicon-perovskite tandem solar cell, setting a new world record for the technology.

The Chinese PV manufacturer presented the result on July 14 during its 2026 Solar and Storage Innovation Technology Conference at Shanghai Jiao Tong University. The result was independently certified by the European Solar Test Installation (ESTI), part of the European Commission’s Joint Research Centre in Italy.

Longi did not disclose the active area or detailed electrical characteristics of the record cell. The reported figure therefore refers to a certified laboratory device rather than a commercial module or mass-production product.

The new result improves on Longi’s previous directly comparable laboratory record of 34.85%, announced in April 2025 and certified by the US National Renewable Energy Laboratory (NREL). The company previously reported certified tandem efficiencies of 31.8% in 2023, 33.9% later that year and 34.6% in 2024.

Longi has also been developing larger-area tandem devices aimed at commercial formats. In June 2025, the company reported a 33% efficiency rating for a 260.9 cm² two-terminal perovskite-silicon tandem cell certified by NREL. The result is not directly comparable with the new 35.5% figure, as larger cell areas introduce additional challenges related to coating uniformity, electrical losses and manufacturing complexity.

The company has not provided a timeline for commercial production of the newly announced device. In June, Longi said it did not have an active mass-production plan for crystalline silicon-perovskite tandem cells. The technology still requires further development in areas including large-area deposition, manufacturing yield, encapsulation, long-term stability and cost reduction.

The efficiency announcement was part of Longi’s “Technology Forest” concept, which groups a range of cell, module and system technologies under a broader technology development framework.

Technologies presented at the event included nano-alloy contact matrix (ACM), integrated conductive backsheet technology, shingled-cell interconnection, hidden busbars, temperature-controlled alloy interconnection, smart module technology, the Longi One OS digital platform and the company’s Three-Proof Pro module design.

Longi said ACM technology has already entered volume production at its 21 GW Xixian cell manufacturing project. While the tandem cell remains at the research stage, the result highlights the efficiency improvements the company is pursuing alongside its back-contact cell technology roadmap.