Shape modification of silver nano triangles under light irradiation

This study focuses on monitoring light induced morphological changes in silver nano triangles using optical extinction spectroscopy (OES) as the primary analytical tool. The spectral shifts observed during irradiationwith light emitting diodes (LEDs) of different wavelengths provided insights into alterations in particle size and shape. These findings were validated through transmission electron microscopy (TEM) , which offered direct visualization of structural evolution and the emergence of new nanoparticle species.To support the experimental analysis, simulations based on Mie theory and the discrete dipole approximation (DDA) were carried out. These models enabled the correlation of extinction spectrum changes with experimentally observed nanoparticle shapes and size distributions, thereby validating the link between optical response and morphological transformation.The silver nano triangles were synthesized via a two step chemical process: spherical nanoparticles were first produced using sodium borohydride (NaBH4) as the reducing agent and polyvinylpyrrolidone (PVP) as the stabilizer. These seeds were subsequently transformed into nano triangles through a shape controlled growthstep involving ascorbic acid and trisodium citrate.This combined optical and structural characterization approach provides an effective methodology for studying the light driven evolution of anisotropic nanostructures, with potential applications in plasmonics, sensing, and photocatalysis.