Radiation-Induced Synthesis of Metal Nanoparticles

Radiation-induced synthesis harnesses high-energy sources—such as gamma rays, electron beams and X-rays—to generate reactive species within a solvent, enabling the direct reduction of metal ions without conventional chemical reductants. Upon irradiation, solvent molecules yield solvated electrons and radical species that initiate nucleation and controlled growth of metallic nuclei. Key parameters—including absorbed dose, dose rate, precursor concentration, pH, presence of scavengers and choice of capping agents—govern particle size, shape and monodispersity. This method offers inherent sterilisation, high purity, narrow size distributions and the capacity for in situ or flow-through production. A broad spectrum of metals and alloys has been accessed, spanning silver, gold, platinum, palladium, copper and bimetallic systems. Owing to their tunable optical and catalytic properties, these nanoparticles find applications in antimicrobial coatings, sensors, catalysis, drug delivery, surface-enhanced spectroscopy and photovoltaics. Current challenges centre on scale-up, uniform irradiation of large volumes and management of radiation safety, while ongoing research seeks deeper mechanistic insight into nucleation kinetics and the interplay between radiation chemistry and colloidal stability.

Research from Nature Portfolio

Recent work has demonstrated the use of synchrotron-generated monochromatic X-rays to drive the in situ radiolytic formation of silver nanoparticles in aqueous polyvinylpyrrolidone solutions. This approach produces narrowly dispersed, spherical nanoparticles of 2–6 nm diameter by exploiting hydrated electrons and radical intermediates to reduce silver salt precursors. The monochromatic beam affords precise spatial and temporal control over reduction kinetics while minimising secondary by-products. Real-time X-ray characterisation during synthesis confirms uniform particle growth and crystallinity, and the resulting plasmonic nanostructures have been shown to enhance light absorption and charge extraction in photovoltaic devices, illustrating the potential of controlled radiolytic routes for energy-harvesting applications.

Radiation-Induced Synthesis of Metal Nanoparticles publication trend

The graph below shows the total number of articles in radiation-induced synthesis of metal nanoparticles across all publications each year (not limited to Nature Index journals).

Technical terms

Radiolysis: Generation of reactive species by high-energy radiation interacting with solvent or solute molecules.

Solvated electron: Highly reactive electron produced in aqueous solution upon radiolysis, capable of reducing metal ions to atoms.

Nucleation: Initial clustering of reduced metal atoms into stable seeds that serve as growth centres for nanoparticles.

Surface plasmon resonance: Collective oscillation of conduction electrons in metal nanoparticles induced by incident light, leading to strong optical absorption.

Capping agent: Molecule adsorbed onto the nanoparticle surface to stabilise particles, prevent aggregation and influence growth kinetics.

References

1. Colloidal Silver Nanoparticles Obtained via Radiolysis: Synthesis Optimization and Antibacterial Properties. Pharmaceutics (2023).
2. Time-domain Tollens reaction: synthesising silver nanoparticles with the formaldehyde clock. Nanoscale Advances (2023).
3. An Overview of the Synthesis of Gold Nanoparticles Using Radiation Technologies. Nanomaterials (2018).
4. Monochromatic X-Ray Induced Novel Synthesis of Plasmonic Nanostructure for Photovoltaic Application. Scientific Reports (2016).