Sungkyunkwan University research offers design guidelines for organic solar cells
From left are Kim Tae-yeon and Ko Doo-hyun, chemistry professors at Sungkyunkwan University, and researchers Ji Seung-hyun and Lee Chi-hyung. Courtesy of Sungkyunkwan University
Findings could help advance commercialization of more efficient materials
A Sungkyunkwan University research team has analyzed an ultrafast process through which electricity is generated in organic solar cells, offering design guidelines for developing more efficient materials.
The university said Monday that the team, led by chemistry professors Kim Tae-yeon and Ko Doo-hyun, conducted the analysis, providing insights for the development of higher-performance solar cell materials.
Organic solar cells are a next-generation clean energy technology prized for their flexibility and transparency.
The silicon solar panels commonly seen on rooftops are heavy and rigid. Organic solar cells, by contrast, use lightweight, thin films that can be bent and shaped, making them a promising technology that could be integrated into windows or even clothing.
More recently, non-fullerene acceptors have emerged as a new class of materials that can significantly improve the efficiency of converting sunlight into electricity.
However, exactly how electricity is generated in these materials at the moment they absorb sunlight has remained uncertain.
To unravel this mystery, the research team systematically analyzed these materials by combining various ultrafast spectroscopy techniques that can observe changes in matter on the femtosecond scale — an extraordinarily brief period equal to one quadrillionth of a second.
Ultrafast spectroscopy is like using an extraordinarily fast camera to capture a sequence of images in rapid succession, allowing scientists to track otherwise invisible movements of tiny particles.
Schematic illustration of charge dynamics in non-fullerene acceptor-based organic photovoltaics and the corresponding ultrafast spectroscopic techniques used to probe these processes. / Courtesy of Sungkyunkwan University
The team carefully compared the strengths and limitations of different measurement techniques and standardized complex technical terms that scientists around the world had been using in different ways.
It also identified why experimental results had differed across previous studies, finding that the discrepancies stemmed from factors such as the wavelengths of light used in different laboratories and the conditions under which the films were fabricated.
Furthermore, the team systematically reviewed existing findings on how molecular structure and nanoscale organization affect charge generation and loss processes. Based on these findings, it proposed design guidelines for high-efficiency organic solar cell materials.
The findings were published in ACS Nano, a leading international journal in nanoscience and materials science, under the title “Carrier Dynamics in Nonfullerene Acceptor Organic Photovoltaics through Ultrafast Spectroscopy.”
Researchers Ji Seung-hyun and Lee Chi-hyung were the paper’s first authors, while professors Kim and Ko served as corresponding authors.
“This paper provides a clear and consistent framework for understanding the complex phenomena that occur in the blink of an eye, offering important guidance for developing higher-performance organic solar cells,” Kim said.
He added, “We hope that the lightweight and flexible nature of organic solar cells will enable their use in a wider range of applications, including wearable power sources and building-integrated photovoltaics.”