BEIJING, March 25, 2026 – A research team led by Professor Meng Qingbo at the Institute of Physics, Chinese Academy of Sciences (CAS), has achieved a new milestone in the field of thin-film photovoltaics, elevating the certified power conversion efficiency of copper zinc tin sulfoselenide (CZTSSe) solar cells to 16.6%. This marks the team's tenth time breaking the world record in this field, underscoring China's global leadership in next-generation photovoltaic technology and signaling that CZTSSe has now crossed the critical threshold for industrialization.
This groundbreaking advancement is the way the world has developed. For more than 10 years of research, CZTSSe is a promising thin-film material because it is made from materials that can be found all over the world, inexpensive, and produce no damage to the environment (Copper, Zinc, Tin, Sulfur and Selenium). Traditional thin film technologies that are often used include cadmium telluride (CdTe) and Copper Indium Gallium Selenide (CIGS); however, these elements are considered to be either very limited in quantity or toxic to the environment, making the research behind CZTSSe an environmentally sustainable alternative for both land-based or space applications.
Overcoming a Decade-Long Bottleneck
Despite its inherent advantages, the development of CZTSSe photovoltaics has long been constrained by a fundamental scientific challenge. As a multi-element compound, the material is prone to complex defect formation, disordered atomic arrangement, and substantial internal energy losses during crystallization. For nearly a decade, these issues brought efficiency improvements to a standstill.
Professor Meng's team addressed this challenge by systematically tackling key scientific problems related to material crystallization, atomic structure, and defect control. The researchers developed an innovative "atomic vacancy strategy" that guides copper and zinc atoms into ordered arrangements, effectively reducing defect activity and internal energy dissipation at their source.
This strategy has yielded great results over the past few years, the team has achieved an incredible amount of progress over the last 3 years including their first energy producing device exceeding an energy efficiency of 13% in 2022. Since then, they have consistently improved their devices with the current energy conversion reaching 16% efficiency while completing development of smaller devices and building Flexible Modules. The team's accomplishments have recently been named one of the Major Scientific and Technological Advances in the PV Industry in China in 2023 and is therefore the sole applicant to be awarded in these two categories. Lastly, Five papers authored by this group in Nature Energy in the years 2023 -2019 have received publications.
Crossing the Industrialization Threshold
According to the established development trajectory of thin-film photovoltaics, an efficiency range of 15%–16% is generally considered sufficient to initiate gradual industrialization. Second-generation thin-film technologies such as CdTe and CIGS entered commercial development after achieving similar laboratory efficiency milestones. With a certified efficiency of 16.6% and its intrinsic advantages in stability, radiation resistance, and material abundance, CZTSSe has now firmly entered the phase of accelerated application demonstration and scaled development.
The team's record-breaking efficiencies have been consistently included in the Solar Cell Efficiency Tables compiled by international photovoltaic experts and the Best Research-Cell Efficiency Chart maintained by the U.S. National Renewable Energy Laboratory (NREL).
Toward Space and Terrestrial Energy Applications
This breakthrough is more than a new milestone in the lab; it is a new milestone for solar energy technology due to major engineering projects placing new demands on solar technologies. Simply put, as the world transitions to cleaner energy sources and deep space exploration continues, major engineering projects (such as low earth orbit (LEO) satellite constellations, solar power from space) are demanding more of solar energy technologies than ever before. This has created strict requirements for solar energy technologies including lower costs, longer lives, lighter weights, and sustainable resources. CZTSSe's unique property combination makes it an excellent fit to meet all of these strict requirements.
"The novel thin-film solar cells we have developed possess multiple advantages, including abundant raw materials, low cost, environmental friendliness, chemical stability, and resistance to space radiation," said Shi Jiangjian, associate researcher at the Institute of Physics, CAS, and a member of Professor Meng's team. "These attributes will enable larger-scale, lower-cost, and more diverse applications of thin-film photovoltaics, providing more versatile and globally competitive options for energy production."
If the CZTSSe technology team can achieve efficiencies of 20% and 18% AND reliable mass production capabilities for cells and modules, respectively, then it will be at full market competitiveness. With its lightweight, flexible, and foldable properties, CZTSSe technology will be widely used for portable energy systems, mobile power supply units, satellites, solar energy platforms in space, and deep-space exploration missions.
A Chinese Contribution to the Global Clean Energy Future
"The horizon of energy production is no longer confined to the Earth's surface; we are now looking toward space-based energy," added Shi Jiangjian. "Our technology is aligned with China's 15th Five-Year Plan's emerging tracks and targets critical fields of the future."
We will continue to support, increase the level of basic research, and support our partners to advance CZTSSe's technology as we all work together to industrialize CZTSSe products. As the world looks for sustainable solutions to solve the world's pressing energy and climate issues, we believe that CZTSSe will be a significant contribution to the world's clean energy future.
