An algorithm helps to find new efficient solar cell materials by reassembling known molecular building blocks of solar cells and simulating the resulting molecules. Picture credits: © MPI-P
Organic, carbon-based materials are already widely used in displays, but they are also promising materials for new solar cells. However, tailoring their properties is time-consuming and requires extensive chemical synthesis and characterization. A new simulation protocol has now been developed at the Max Planck Institute for Polymer Research, which combines already known molecular building blocks into new structures and correlates them with the solar cell efficiency, thus significantly simplifying development processes.
Organic solar cells could play a key role in the energy transition. However, a cheap synthesis route and high cell efficiency make a significant contribution to supporting this transition. The discovery of a new class of materials known as “non-fullerene acceptors” offers a cost-effective synthesis route compared to the more traditional silicon solar cells, while offering higher efficiency than the first organic solar cells.
The design of these “non-fullerene acceptor” materials with properties tailored for use in solar cells still poses challenges. In the group of Denis Andrienko, department of Kurt Kremer at the Max Planck Institute for Polymer Research, and colleagues, a new simulation-based design methodology has now been developed to simplify this process. The design methodology leverages well-known high-efficiency organic solar cells by dividing them into multiple building blocks. These fragments consist of either electron-donating or electron-accepting molecular components called “acceptors” and “donors”. Donor and acceptor building blocks from various known solar cells can be combined to yield new “non-fullerene acceptor” molecules for use in solar cells.
“It is a challenge to choose the right one from the large number of existing molecular compounds – that’s why we use our method to access existing solar cells and combine their molecular components to form new solar cells,” says Kun-Han Lin, a co-author of the study.
The design algorithm contains constraints that reduce the number of possible “non-fullerene acceptor” molecules – such as molecular symmetry, quadrupole moment, ionization energy, and electron affinity. For example, in cases where an acceptor-donor-acceptor combination is used, the two acceptor building blocks are always of the same type.
This design methodology is already showing promise, helping to predict solar cell efficiency before the materials are actually synthesized.
“We were thrilled when we found that our method works: 10 of 12 predicted efficient solar cells have already been produced and are highly efficient,” said Andrienko.
They have published their work in the renowned journal Advanced energy materials.
Reference: “Chemical Design Rules for Non-Fullerene Acceptors in Organic Solar Cells” by Anastasia Markina, Kun-Han Lin, Wenlan Liu, Carl Poelking, Yuliar Firdaus, Diego Rosas Villalva, Jafar I. Khan, Sri HK Paleti, George T. Harrison, Julien Gorenflot, Weimin Zhang, Stefaan De Wolf, Iain McCulloch, Thomas D. Anthopoulos, Derya Baran, Frédéric Laquai and Denis Andrienko, October 8, 2021, Advanced energy materials.
DOI: 10.1002/aenm.202102363
