title: Biological synthesis of triangular gold nanoprisms.
abstract: The optoelectronic and physicochemical properties of nanoscale matter are a strong function of particle size. Nanoparticle shape also contributes significantly to modulating their electronic properties. Several shapes ranging from rods to wires to plates to teardrop structures may be obtained by chemical methods; triangular nanoparticles have been synthesized by using a seeded growth process. Here, we report the discovery that the extract from the lemongrass plant, when reacted with aqueous chloroaurate ions, yields a high percentage of thin, flat, single-crystalline gold nanotriangles. The nanotriangles seem to grow by a process involving rapid reduction, assembly and room-temperature sintering of 'liquid-like' spherical gold nanoparticles. The anisotropy in nanoparticle shape results in large near-infrared absorption by the particles, and highly anisotropic electron transport in films of the nanotriangles.
authors.affiliation: Materials Chemistry, National Chemical Laboratory, Pune-411 008, India.
authors.forename: S Shiv
authors.initials: SS
authors.lastname: Shankar
authors.forename: Akhilesh
authors.initials: A
authors.lastname: Rai
authors.forename: Balaprasad
authors.initials: B
authors.lastname: Ankamwar
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: D000447:Aldehydes / Q000737:chemistry; D002151:Calorimetry / Q000379:methods; D002712:Chlorides / Q000737:chemistry; D019343:Citric Acid / Q000737:chemistry; D031743:Cymbopogon / Q000737:chemistry*; D004563:Electrochemistry / Q000379:methods; D017612:Gold Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D007659:Ketones / Q000737:chemistry; D007834:Lasers; D018625:Microscopy, Atomic Force; D008854:Microscopy, Electron; D036103:Nanotechnology / Q000379:methods; D010084:Oxidation-Reduction; D010316:Particle Size; D010936:Plant Extracts / Q000737:chemistry; D012542:Scattering, Radiation; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties
chemical_list: D000447:Aldehydes; D002712:Chlorides; D017612:Gold Compounds; D007659:Ketones; D010936:Plant Extracts; D019343:Citric Acid; C024568:gold tetrachloride, acid