Chinese researchers set world record for tandem solar cell efficiency

A team of Chinese researchers has achieved a certified power conversion efficiency of 28.04% for a perovskite-organic tandem solar cell, setting a world record for the technology and bringing it a step closer to practical applications, according to a study published in Nature on Sunday.

The research was led by Academician Li Yongfang and researcher Meng Lei from the Institute of Chemistry under the Chinese Academy of Sciences.

Unlike conventional single-junction solar cells, such as the silicon photovoltaic panels widely used on rooftops and in solar farms, tandem solar cells stack two light-absorbing materials on top of each other. Each layer captures a different part of the solar spectrum, allowing the cells to convert sunlight into electricity more efficiently while remaining thin, lightweight and flexible.

The technology is considered promising for applications where lightweight power sources are needed, including building-integrated photovoltaics, portable energy systems, wearable electronics, drones and spacecraft.

To address long-standing challenges involving performance degradation and limited stability, the researchers introduced a new additive molecule known as TDB. The molecule regulates the material throughout both the fabrication process and operation under illumination, offering a potential solution to one of the technology's key bottlenecks.

Third-party certification showed the solar cell achieved a steady-state power conversion efficiency of 28.04%, setting a new world record for perovskite-organic tandem solar cells. It also demonstrated strong operational stability, retaining 90% of its initial efficiency after 625 hours of continuous illumination.

According to the researchers, the technology could eventually be adapted for a range of applications, including buildings, transportation, wearable electronics, and satellites, where lightweight, flexible solar cells could offer advantages over conventional photovoltaic panels.