title: Role of halide ions and temperature on the morphology of biologically synthesized gold nanotriangles.
abstract: In this paper, we demonstrate the effect of halide ions on the formation of biogenically prepared gold nanotriangles using the leaf extract of lemongrass (Cymbopogon flexuosus) plant. We have also studied the effect of halide ions on the morphology of biogenic nanotriangles. It has been shown that iodide ions have a greater propensity to transform flat gold nanotriangles into circular disk-like structures as compared to other halide ions. The study also suggests that the presence of Cl- ions during the synthesis promotes the growth of nanotriangles, whereas the presence of I- ions distorts the nanotriangle morphology and induces the formation of aggregated spherical nanoparticles. The change in the morphology of gold nanotriangles has been explained in terms of the ability of the halide ions to stabilize or inhibit the formation of (111) faces to form [111] oriented gold nanotriangles. Last, we have also shown that the temperature is an important parameter for controlling the aspect ratio and the relative amounts of gold nanotriangles and spherical particles. The results show that, by varying the temperature of reaction condition, the shape, size, and optical properties of anisotropic nanoparticles can be fine-tuned.
authors.affiliation: Nanoscience Group, Materials Chemistry Division, National Chemical Laboratory, Pune 411 008, India.
authors.forename: Akhilesh
authors.initials: A
authors.lastname: Rai
authors.forename: Amit
authors.initials: A
authors.lastname: Singh
authors.forename: Absar
authors.initials: A
authors.lastname: Ahmad
authors.forename: Murali
authors.initials: M
authors.lastname: Sastry
mesh_terms: D016880:Anisotropy; D002713:Chlorine / Q000737:chemistry; D031743:Cymbopogon / Q000737:chemistry; D017612:Gold Compounds / Q000138:chemical synthesis*; D006219:Halogens / Q000737:chemistry*; D007455:Iodine / Q000737:chemistry; D007477:Ions; D008422:Materials Testing; D018625:Microscopy, Atomic Force; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D010936:Plant Extracts / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet; D013499:Surface Properties; D013696:Temperature
chemical_list: D017612:Gold Compounds; D006219:Halogens; D007477:Ions; D010936:Plant Extracts; D002713:Chlorine; D007455:Iodine