Triangular silver nanoplates (T‐SNPs) are synthesized via a facile, low‐cost photochemical process. It is proved that both the pH and the concentration of trisodium citrate (TSC) are the key factors to describe the mechanism for the photochemical growth and modulation of the extinction band along the formation of T‐SNPs. A precise photoreduction growth mechanism of T‐SNPs is proposed and confirmed by X‐ray photoelectron spectroscopy (XPS) considering the face block theory and the localized surface plasmon resonance (LSPR) in T‐SNPs revealing the optimal conditions for their growth to be at a neutral pH of 7, a concentration between 1.0 and 2.0 mm of TSC preferentially monodentate, and using a 520 nm excitation energy. These results exhibit important implications for the behavior of T‐SNPs in a wide variety of plasmonic applications that can be further moved to controlled surface‐enhanced biomedical applications.

Optimizing the antibacterial properties of nanocomposites is a fundamental challenge for many biomedical applications. Here, we study how we may optimize the antibacterial activity of narrow-sized anisotropically flat silver nanoprisms (S-NPs) on graphene oxide (GO) against Escherichia coli. To do so, we transformed silver nanoparticles (AgNPs) into S-NPs and anchored them to GO via a facile and low-cost photochemical reduction method by varying the irradiation wavelength during the synthesis process in the visible range (440 to 650 nm and white light). We performed a physicochemical characterization of the resulting S-NP/GO nanocomposite using a combination of UV–vis spectroscopy, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Our results reveal a synergistic effect between the silver nanoprism and the oxygen functional groups of the GO surface. The antibacterial activity of the S-NPs/GO nanocomposite shows a significantly higher 53% inhibition efficiency after being irradiated with a 540 nm wavelength light source, compared to AgNPs with a 1% inhibition efficiency, respectively. In so doing, we have demonstrated the utility of a low-cost photoreduction method to control the structural properties of silver nanoprism on GO and, in this way, enhance the antibacterial properties of the nanocomposite. These results should be of great interest in a wide range of biomedical applications and medical devices.