A research team, led by Northwestern scientists, has developed a method that could moves perovskite solar cells closer to industry adoption and widespread use. Using liquid crystals that can respond to temperature change and avoid accumulating precipitation, the group enabled the protection of large-area perovskite films.
This approach led to a 22% efficiency and a stabilized efficiency of 21% for solar modules with enhanced damp heat (85% relative humidity at 85 degrees Celsius) stability and a size of 31 sq. centimeters.
According to the team, before this effort, the highest certified stabilized aperture-area efficiency for perovskite solar modules exceeding 30 sq. centimeters was observed to plateau at approximately 19.5%. To reach a higher level, the team developed a new material processing method to achieve uniform protection from defects on large-scale perovskite films, enabling the record stabilized efficiency.
“The liquid crystal strategy helps address a critical issue in the scale-up of perovskite solar cells, which demonstrates the potential for more efficient and stable solar energy generation on a larger scale, making it more robust for real-world applications,” said Yi Yang, a postdoctoral fellow in the research groups of Professors Ted Sargent and Mercouri Kanatzidis. “From a practical perspective, it underscores the limitation of applying well-established methods for small-sized devices to large-scale implementations. It highlights the necessity for developing tailored solutions to minimize performance gaps in the scale-up process.”
Prior research on liquid crystals used them as common additives in perovskite films but overlooked their ability to change with temperatures. Their use in this fashion potentially allows the regulation of crystal growth and prevention of defects in large-area perovskite films.
The novel idea also presents more potential applications in the future.
“This methodology can be extended to the slot-die coating process, facilitating the production of larger-area perovskite submodules,” Yang said. “Exploring the functionality and phase structure of liquid crystal molecules presents an opportunity to enhance passivation effects and bolster device stability.”
