Ultrafast stabilization of positive charges revealed in solar fuel catalyst

by Riko Seibo

Tokyo, Japan (SPX) Oct 27, 2025

Researchers have used advanced quantum-chemical molecular dynamics simulations to capture the ultrafast formation of charge-stabilizing polarons in NaTaO3, a benchmark photocatalyst for solar water splitting. The work reveals that positive charges, or hole polarons, stabilize far more rapidly and strongly than electrons, providing key insights for engineering next-generation solar fuel catalysts.

The simulations showed that hole polarons undergo stabilization of about 70 meV within just 50 femtoseconds, driven mainly by elongation of oxygen-tantalum bonds. This contrasts with electron polarons, which remained delocalized and displayed negligible stabilization. These results explain why holes play a dominant role in driving catalytic reactions in NaTaO3.

The team overcame experimental limits by employing Born-Oppenheimer molecular dynamics with an accelerated divide-and-conquer density-functional tight binding approach. This enabled atomistic, real-time visualization of carrier dynamics within a nanoscale model of NaTaO3 containing 256 formula units, tracked at 1 femtosecond resolution.

According to the researchers, the two-step stabilization pathway begins when a hole localizes near pre-elongated O-Ta bonds, which then stretch further during structural relaxation. The strong correlation between bond elongation and hole energy stabilization highlights O-Ta bonding as a critical design target.

The findings align with prior experimental evidence of trapped carriers and open the way for rational catalyst design. By focusing on the B-site chemistry of perovskites, future materials may be engineered to fine-tune O-Ta interactions, prolong hole lifetimes, and boost solar hydrogen production efficiency.

Research Report:Quantum-chemical molecular dynamics study of polaron formation in perovskite NaTaO3 as a water-splitting photocatalyst

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