A new method increases the efficiency of organic solar cells
The integration of polymeric insulators into organic solar cells has led to major advances in this field, addressing challenges in molecular conformation, film crystallinity, and defect state reduction. Traditionally, these improvements were attributed to improved film morphology due to insulating materials. However, a new discovery by Professor Hang Yin’s team at Shandong University has revealed a previously unknown mechanism driving performance improvements in organic semiconductors.
The research introduces the concept of the “insulator-donor electron wave function coupling effect”, which provides a new approach for improving electron mobility in donor systems. The team showed that mixing DA-type donor polymers with insulating materials with electron-rich side chains can enhance electron mobility by up to 100 times. This phenomenon differs from previous mechanisms based on morphological optimization.
Theoretical calculations revealed that the electron-rich groups in the insulating material directly couple with the D unit of the donor polymer, lowering the energy barrier for electron transport. This coupling significantly improves electron movement within the chain, a conclusion supported by experimental data.
Taking advantage of this coupling effect, the researchers fabricated PM6/L8-BO pseudo-bilayer organic solar cells, achieving a record-breaking energy conversion efficiency (PCE) of 19.50% (certified at 19.18%). The findings provide a new perspective on quantum effects in polymeric insulators while proposing a simple and effective method to improve the performance of organic solar cells.
The findings were published in National Science Review under the title “Insulator-Donor Electron Wavefunction Coupling in Pseudo-Bilayer Organic Solar Cells Achieving A Certified Efficiency of 19.18%.” The co-first authors of the study include Jiangkai Sun (PhD, Shandong University), Xue Yang (master’s student, Shandong University) and Ruijie Ma (postdoctoral researcher, Hong Kong Polytechnic University). Professors Hang Yin, Xiaotao Hao, Kun Gao (Shandong University), and Gang Li (Hong Kong Polytechnic University) served as corresponding authors.
Research report:Coupling of insulator-donor electron wave function in pseudo-bilayer organic solar cells achieving a certified efficiency of 19.18%
