Recently, the research team of Professor WANG Mingtai at the Institute of Solid State Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences developed a low-temperature solution-processing strategy for fabricating CuInS 2 thin-film solar cells, and achieved a CuInS 2 solar cell with an efficiency up to 12.28%.
Their findings were published in Joule .
Photovoltaic energy is a promising source of renewable and sustainable power, but developing solar cells that are efficient, stable, and low-cost remains a major challenge. Chalcogenide materials, such as CuInS 2 , are attractive candidates due to their high light absorption, suitable band gaps, and good stability. However, their development has stalled for nearly three decades since achieving 12.2% efficiency in high-temperature-processed devices in 1996.
In this study, the team developed a low-temperature solution-processing strategy that combines two key technological innovations.
They designed an interdigitation architecture in an indium-rich CuInS 2 absorber layer at temperatures below 300 °C, which overcomes the limitations of conventional bilayer structures caused by short charge diffusion lengths and enhances both photon absorption and charge generation. In addition, they introduced a sulfur anion-induced gradient phase transformation (S 2- -GPT) process at 180 °C, effectively reducing shallow- and deep-level defects to reduce non-radiative recombination and creating an internal electric field that improves the transport of photogenerated charges.
With these innovations, the CuInS 2 solar cell reached an efficiency of 12.28%, slightly higher than the previous record of 12.2%, and an open-circuit voltage of 0.83 V, indicating a strong power-generating capability. Impressively, even without encapsulation, the device retained 86.3% of its initial efficiency after 500 days under ambient conditions, showing an outstanding long-term stability and demonstrating that low-temperature processing can produce both efficient and durable solar cells.
This work provides a scalable, low-cost, and stable CuInS 2 -based solar cell platform, offering a promising alternative to perovskite solar cells, which still face stability challenges.
Joule
A low-temperature strategy to prepare CuInS2 solar cells with efficiency exceeding 12%
20-May-2026