Researchers in Bengaluru have developed a promising metal-free organic material that could improve the efficiency of solar-driven water splitting for green hydrogen production. The new approach combines a naturally occurring amino acid with a light-absorbing organic molecule, demonstrating how molecular self-organization can significantly enhance photocatalytic performance.
The study was carried out by scientists at the Centre for Nano and Soft Matter Sciences (CeNS), Bengaluru, an autonomous institute under the Department of Science and Technology (DST). The research focuses on addressing one of the key challenges in the development of sustainable photocatalysts for solar energy conversion.
Developing Sustainable Photocatalysts
Hydrogen is widely regarded as a clean energy carrier because its use can produce water as the primary by-product. Solar-powered water splitting, which uses sunlight to separate water into hydrogen and oxygen, is therefore considered an important pathway towards green hydrogen.
However, many conventional photocatalytic systems depend on inorganic semiconductor materials or precious metals. Their high cost, complex manufacturing requirements and dependence on scarce resources can limit their wider application. The development of efficient, stable and completely metal-free organic photocatalysts could offer a more sustainable alternative.
To address this challenge, the CeNS research team combined aspartic acid, a naturally occurring amino acid, with perylene diimide (PDI), an organic molecule capable of absorbing light. The resulting molecule was designed to spontaneously organize itself in water through a process known as supramolecular self-assembly.
Molecular Self-Assembly Boosts Performance
The researchers found that the arrangement of molecules played a crucial role in improving the material’s properties. The aspartic acid component encouraged strong and extended hydrogen bonding, while the PDI component facilitated π–π stacking and efficient absorption of light.
Together, these interactions enabled the molecules to form highly ordered two-dimensional nanosheets when dispersed in water. This structural transformation occurred without changing the chemical composition of the individual molecules.
According to the researchers, the self-assembled structure produced several advantages. It expanded the range of light absorbed by the material, improved the separation of photo-generated charges, lowered energy losses and increased the available surface area for catalytic reactions.
These combined effects resulted in substantially improved photocatalytic activity. During solar-driven water splitting experiments, the self-assembled material produced nearly 18 per cent higher photocurrent compared with its bulk counterpart.
Insights from Advanced Analysis
The team also used advanced electrochemical measurements and density functional theory (DFT) calculations to understand why the self-assembled material performed better.
The analysis indicated that molecular self-assembly enabled more effective charge transport within the material. At the same time, the incorporation of aspartic acid increased the molecular dipole moment, helping separate photo-generated charges more efficiently.
Efficient charge separation is particularly important in photocatalytic water splitting because it reduces the likelihood of electrons and holes recombining before they can participate in chemical reactions. The improved charge dynamics therefore support the processes required for hydrogen generation.
Potential for Green Energy Technologies
The findings highlight the potential of naturally occurring molecules to play a much larger role in the design of advanced solar-energy materials. Rather than serving only as structural components, amino acids can be used to control molecular organization and influence the functional performance of organic photocatalysts.
The research was led by Dr. Goutam Ghosh and Dr. Ashutosh K. Singh at CeNS, Bengaluru, along with Sourav Moyra, Kumar Shubham and Athira Chandran M. The study has been published in the Journal of Materials Chemistry A, a leading journal of the Royal Society of Chemistry.
The molecular design strategy could eventually support the development of sustainable materials for green hydrogen production, artificial photosynthesis and solar-fuel technologies. It may also contribute to next-generation renewable energy devices while reducing dependence on costly and scarce metals.
Author: Shivam
Shivam Dwivedi is a senior journalist with extensive experience in research-driven journalism, policy communication, and multi-platform storytelling. His areas of interest include international relations, defence, science & technology, education, urban development, agriculture, spirituality, and environmental sustainability. His work focuses on in-depth analysis, public discourse, and impactful narratives across governance and development sectors, with a strong commitment to the Sustainable Development Goals (SDGs). Contact: [email protected]
