Fraxinus paxiana bark mediated photosynthesis of silver nanoparticles and their size modulation using swift heavy ion irradiation

• Silver nanoparticles are synthesized using Fraxinus paxiana var. sikkimensis bark.
• Presence of sunlight and/or UV irradiation is essential for the synthesis.
• 100 MeV Ag8+ irradiation on the bark assists in synthesizing smaller nanoparticles.
• The synthesized nanoparticles exhibit effective antimicrobial properties.

Photosynthesis of silver nanoparticles is presented using bark extracts of Fraxinus paxiana var. sikkimensis. The synthesized nanoparticles are characterised by UV–Vis absorption, photoluminescence, powder X-ray diffraction and scanning and transmission electron microscopy. In addition, the bark samples are irradiated with 100 MeV silver ions and the subsequent structural modifications are analyzed. The swift heavy ion irradiated Fraxinus paxiana var. sikkimensis bark is also used for the synthesis of silver nanoparticles. It is illustrated that the irradiated bark assists in synthesizing smaller nanoparticles of homogenous size distribution as compared to when the pristine bark is used. The newly synthesized silver nanoparticles are also used to demonstrate the antimicrobial activities on Escherichia coli bacteria.