Cientistas desvendam segredo da fotossíntese que pode revolucionar energia verde

by Sungkyunkwan University

edited by Swati Mestri, reviewed by Alexander Pol

This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility:

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A research team led by Taeyeon Kim, a professor in the Department of Chemistry at Sungkyunkwan University, in collaboration with a team from Yonsei University, has identified a new principle that controls charge separation, a phenomenon that plays a central role in both plants' generation of electrical energy (photosynthesis) and next-generation molecular semiconductor devices.

The findings were published in Nature Communications.

When plants absorb sunlight to generate energy, they rapidly separate and transfer charge within their internal structures. Inspired by this process, the scientific community has long sought to develop next-generation energy devices such as artificial photosynthesis systems and organic solar cells. Molecular aggregate structures formed by densely stacked "perylene bisimide (PBI)," an organic semiconductor molecule known for its excellent electron-accepting properties, have drawn particular research attention. However, the complex environment created by tightly clustered molecules has made it difficult to precisely determine how the surrounding environment alone affects charge transfer.

To address this, the research team developed a proprietary PBI molecular aggregate platform that allows the polarity of the surrounding solvent (liquid) to be selectively varied while keeping the molecules' stacked nanostructure unchanged. The team applied ultrafast laser spectroscopy, capable of capturing subtle changes in light at the femtosecond scale (one quadrillionth of a second), to this aggregate platform and supported the results with quantum chemical computations.

The results revealed, for the first time, a phenomenon in which the mechanism of charge transfer completely switches depending on the properties of the surrounding solvent—a so-called "mechanism crossover." In low-polarity solvents, such as oil, charge transfer was driven by quantum-mechanical tunneling (a quasi-classical regime), in which molecules pass through energy barriers via subtle vibrations. In high-polarity solvents, such as water or alcohol, charge transfer was instead governed by the collective fluctuation of surrounding solvent molecules (a classical regime).

The team further demonstrated that under strong light exposure, the "exciton diffusion length"—the effective distance over which light energy travels—could be tuned from 35.9 nanometers (nm) to 98.8 nanometers depending on the surrounding solvent environment. This opens a pathway for energy within organic semiconductors to be transferred more efficiently over longer distances without loss.

"This study is significant in that it isolated the influence of the dielectric environment alone, without structural distortion, within a complex molecular aggregate, thereby revealing the fundamental principle of charge transfer," Kim said. "We expect this to provide integrated molecular design guidelines that can maximize the efficiency of environmentally friendly future energy devices such as organic solar cells and artificial photosynthesis systems."

Hyeonwoo Choi et al, Dielectric-tuned charge and exciton dynamics in perylene bisimide supramolecular aggregates, Nature Communications (2026). DOI: 10.1038/s41467-026-75555-y

Journal information: Nature Communications

Provided by Sungkyunkwan University

Swati Mestri holds a bachelor's degree in Electronics Engineering and has worked as a content editor since 2019. She has experience editing research documents across technology, health care, and materials science, and has a particular interest in technology and space. Full profile →

PhD nano-engineering from Delft University. Published researcher and journal reviewer. Brings scientific insight to content standards. Full profile →

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