35.5%! LONGi Once Again Breaks World Record for Crystalline Silicon-Perovskite Tandem Solar Cell Efficiency

The solar panel maker LONGi has set a new efficiency record for a type of solar cell that stacks two light-absorbing layers together instead of one. These "tandem" cells pair standard crystalline silicon with a material called perovskite, letting the panel capture more of the sun's energy than a typical single-layer silicon cell can. LONGi's latest version converts 35.5% of sunlight into electricity, certified by an independent European testing lab. Most silicon panels on the market today top out well below that, since a single-layer cell has a hard physical ceiling of around 33.7% efficiency. This tandem approach has a theoretical limit as high as 43%.

This is a lab result, not a shipping product. LONGi has been climbing steadily toward this number over the past couple of years, and it has also tested the technology on larger, more industrial-sized cell samples and on assembled tandem panels, with lower but still strong efficiency numbers in those bigger formats. That gap between small lab records and full-size manufactured panels is normal for new solar technology and usually takes years to close.

For a homeowner, the practical takeaway is simple: this is an early signal that future solar panels could squeeze more power out of the same roof space, which would matter for anyone with a small or shaded roof where every bit of panel efficiency counts. But panels using this technology are not yet available to buy, and no timeline for that was given.