Stacking molecules like plates improves organic solar device performance

A research team from Osaka University has made significant advancements in the efficiency of organic solar cells by manipulating the stacking of light-absorbing molecules. The study highlights that the performance of organic optoelectronic devices, such as solar cells, is closely linked to the exciton-binding energy of the materials used. Lower exciton-binding energy facilitates the generation of free-charge carriers, which are essential for electric current. The researchers synthesized two types of star-shaped molecules—one with a flexible center and another with a rigid center. While both types behaved similarly in solution, their performance diverged when stacked in solid films. The rigid molecules stacked more effectively, resembling plates, which resulted in a lower exciton-binding energy and enhanced device performance. The findings suggest that optimizing molecular aggregation can lead to more efficient optoelectronic devices. This research, published in Angewandte Chemie International Edition, emphasizes the importance of molecular interactions in solid states and proposes a new design approach for future optoelectronic materials.

- Osaka University researchers improved organic solar cell efficiency by controlling molecular stacking.

- Lower exciton-binding energy enhances the generation of free-charge carriers in solar cells.

- Rigid star-shaped molecules performed better than flexible ones when stacked in solid films.

- The study suggests that molecular aggregation is crucial for optimizing device performance.

- Findings could inform the design of next-generation optoelectronic devices.