US patent office sides with First Solar on TOPCon tech

The U.S. Patent and Trademark Office has sided with First Solar across three attempts to invalidate its patents for TOPCon solar cell technology, the company announced Tuesday.

Last year, Jinko Solar, Canadian Solar and Mundra Solar filed separate inter partes reviews (IPR) applications as First Solar pursued patent infringement lawsuits against all three in the United States District Court for the District of Delaware.

The Director of the United States Patent and Trademark Office declined the applications between Nov. 20 and Dec. 18.

“The USPTO’s decision reinforces our belief in the strength of our TOPCon technology patent portfolio,” said Jason Dymbort, First Solar’s Executive Vice President, General Counsel and Secretary. “As we’ve consistently stated, we will actively defend our intellectual property rights in the US and internationally and continue to pursue legal action against these and other manufacturers, as we work to enforce our patent rights.”

In July 2024, First Solar said it could challenge companies found to be in violation of its TOPCon patents, which it received in its acquisition of TetraSun in 2013. First Solar makes thin-film cadmium telluride modules and has not produced TOPCon modules of its own since 2016.

In October of that year, the company said it was moving ahead with an investigation into potential infringement of its TOPCon patents. Attorneys sent letters of notice to “several leading crystalline silicon solar manufacturers,” and began negotiations with other interested parties for rights to the technology.

Texas-based solar cell producer Talon PV announced in February 2025 that it had secured a license from First Solar to begin producing n-type solar cells starting in 2026.

Reporting by Colt Shaw, cshaw@opisnet.com; Editing by Jordan Godwin, jgodwin@opisnet.com