LONGi Green Energy Leads Breakthrough in Flexible Stacking Technology, Selected as One of China's Top Ten Scientific Advances

The 2026 Zhongguancun Forum Annual Conference will open in Beijing on March 25, with the official announcement of the “Top Ten Scientific Advances in China for 2025.” The “High-Efficiency and Stable Flexible Perovskite-Silicon Tandem Solar Cell Technology,” developed jointly by LONGi Green Energy Technology Co., Ltd. and Suzhou University, is among the listed achievements, marking a significant breakthrough in China’s next-generation photovoltaic core technology. This is also one of the two major scientific advances from Shaanxi Province that made the list.

This year’s forum is themed “Deep Integration of Technological Innovation and Industrial Innovation.” The selected achievements exemplify the deep integration of industry, academia, and research, as well as collaborative innovation. LONGi Green Energy is currently the only photovoltaic company in the world with the capability to manufacture wafer-sized ultra-thin flexible tandem cells.

Currently, the laboratory’s highest conversion efficiency for traditional monocrystalline silicon cells has approached the theoretical limit of 29.4%. By constructing a tandem structure with perovskite materials and silicon, it can fully utilize sunlight of different wavelengths, with a theoretical efficiency exceeding 43%, recognized as a next-generation disruptive photovoltaic technology. Among them, flexible tandem cells based on ultra-thin silicon wafers, with their extraordinary lightweight and bendable characteristics, are expected to unlock frontier applications such as wearable devices and building-integrated photovoltaics. However, flexible devices face challenges as repeated bending and temperature changes can easily lead to interface delamination failure, with stability and lifespan far inferior to rigid devices, which has long constrained their commercialization process.

To address this core challenge, LONGi Green Energy’s team led by Li Zhengguo, Xu Xixiang, and He Bo collaborated with the team of Professors Zhang Xiaohong and Liu Jiang from Suzhou University to innovatively design a “tight and loose” double-buffer layer structure. The loose layer can absorb and dissipate strain energy like a spring mattress, alleviating mechanical stress; the dense layer ensures efficient interface charge extraction and a solid connection. This “rigid-flexible integration” nanometer-scale layered design provides a “durable armor” for flexible tandem cells.

The ultra-thin flexible tandem cells (approximately 60 micrometers) produced based on this technology have achieved certification from the U.S. National Renewable Energy Laboratory at the laboratory size, with an efficiency of 33.4%; at the full wafer size, the efficiency reached 29.8%, both setting world records for this type of device. Its power-to-weight ratio is as high as 1.77 watts/gram, showcasing significant lightweight advantages.

Being selected as one of the national annual top ten scientific advances not only highly recognizes the scientific research capabilities of LONGi Green Energy and its collaborative team but also lays a solid foundation for the application of flexible tandem technology. Industry experts believe that this achievement will strongly promote the transition of China’s photovoltaic industry from “efficiency leadership” to “scene leadership,” contributing Chinese wisdom to the global energy transition.

Written by Zhong Xinyuan