A domestic research team has developed a technology that can significantly boost efficiency in the solar cell manufacturing process by adjusting how quickly the temperature is raised.
A team led by senior researchers Yang Gi-jung and Kim Dae-hwan of the Daegu Gyeongbuk Institute of Science and Technology (DGIST) Energy and Environmental Research Division, together with a team led by Professor Kim Jun-ho of the University of Incheon, said on Oct. 20 that they confirmed that when materials are thermally processed, rapidly raising the temperature leads to orderly crystal growth and fewer defects, allowing current to flow smoothly.
Antimony selenide (Sb₂Se₃), used by the research team, is an eco-friendly material made only from antimony and selenium, which are abundant on Earth, without harmful substances such as cadmium or lead. The material absorbs light well, is robust against heat and chemical reactions, and can be mass-produced at low cost.
Conventional materials exhibited irregular crystal growth with many defects, hindering smooth current flow and lowering efficiency. To address this, the team experimented with controlling the rate at which temperature is raised during solar cell fabrication—that is, the crystal growth rate.
As a result, when the temperature was raised rapidly, crystals grew neatly in a uniform direction and defects decreased, allowing current to flow without blockage. Conversely, when the temperature was raised slowly, crystals formed irregularly and defects increased, impeding current flow. The team verified this in detail using various instruments, including a scanning electron microscope and X-ray diffraction.
The experiments confirmed that rapidly raising the temperature leads to crystals growing neatly in a uniform direction with fewer defects, enabling unobstructed current flow. Conversely, slowly raising the temperature caused crystals to form irregularly, increased defects, and hindered charge transport. The team confirmed this using various analytical techniques, including scanning electron microscopy, X-ray diffraction, and ultraviolet photoelectron spectroscopy.
Yang, a DGIST senior researcher, said, "This study provides a clue to solving the key issues of crystal orientation and defects in antimony selenide solar cells," adding, "By controlling only the initial crystal growth rate in the process, we can maximize the material's potential, which will greatly aid commercialization and the development of large-area modules."
The findings were published last month in the leading energy journal Journal of Materials Chemistry A and were selected as an inside cover paper.
References
Journal of Materials Chemistry A (2025), DOI: https://doi.org/10.1039/D5TA05256D