Does Photovoltaics Change Gear? The New Chinese Cell Achieves an Impressive 35.5% Efficiency

The Chinese manufacturer LONGi has announced that it has reached a new milestone in the development of tandem solar cells using crystalline silicon and perovskite. The company claims to have achieved a conversion efficiency of 35.5%, a result certified by the European Solar Test Installation (ESTI), an international reference laboratory for the calibration and verification of photovoltaic device performance.

This figure represents a significant increase compared to the technologies currently available on the market. The most advanced commercial photovoltaic panels achieve efficiencies close to 25%, while values above 35% had until now been mostly confined to experimental or highly specialized applications.

There are cells capable of exceeding 50% efficiency, but these are multi-junction devices intended for niche uses, such as the space sector, where cost is a secondary factor compared to performance.

The technology developed by LONGi combines a traditional crystalline silicon cell with a layer of perovskite, a material that has attracted growing interest in recent years for its ability to absorb complementary portions of the solar spectrum compared to silicon. This tandem architecture allows for a reduction in energy losses typical of conventional cells and, at least theoretically, can achieve a maximum efficiency of 43%, surpassing the Shockley-Queisser limit of 33.7% for single-junction cells.

The new result is the latest stage in a progression that began in November 2023 when LONGi announced an efficiency of 33.9%, which was then improved to 34.6% in June 2024. Over the past twelve months, the research group has continued to gradually improve performance, moving from 34.85% to 35.2%, now reaching the current 35.5%.

According to the company, the previous result of 35.2% was included in May in the 68th edition of the Solar Cell Efficiency Tables, the international collection curated by the group led by Professor Martin Green of the University of New South Wales, considered one of the main global references for monitoring the performance of photovoltaic cells.

LONGi also emphasizes that advances are not limited to small laboratory cells. The company reports achieving an efficiency of 34.3% on a cell measuring 261 cm² and 32.2% on one measuring 274 cm², values presented as indicative of the potential path toward industrial production.

Even in terms of complete modules, improvements have been recorded, with efficiencies of 31.4% and 29.4%, both certified by international bodies and included in the official efficiency tables. The company defines 35.5% as a new world record for tandem cells made of crystalline silicon and perovskite. However, it should be noted that, considering all photovoltaic technologies, there are experimental devices with even higher performances: for instance, the U.S. National Renewable Energy Laboratory (NREL) had already presented a cell with a 39.5% efficiency back in 2022.

Beyond the competition for records, the main challenge remains that of mass production. Silicon-perovskite tandem cells are considered one of the main candidates for the next generation of high-efficiency photovoltaic panels, but their widespread adoption will depend on the ability to transfer the results obtained in laboratories to economically sustainable and reliable production processes in the long term.

LONGi states that it will continue its development according to a strategy that includes technologies already in production, solutions under development, and research platforms for future generations of products, with the goal of accelerating the transition to increasingly efficient photovoltaic systems.