Synthesis of Indium Nanoparticles: Digestive Ripening under Mild Conditions

Abstract

Here we report the synthesis of monodispersed indium nanoparticles by evaporation/condensation of indium shot using the solvated metal atom dispersion (SMAD) technique, followed by digestive ripening in low boiling point (BP 38 °C) methylene chloride and in a high boiling point (BP 110 °C) toluene solvent. The as-prepared SMAD indium nanoparticles are polydispersed with particle size ranging from 25 to 50 nm, but upon digestive ripening (heating of colloidal material at the boiling point of solvent in presence of excess surface active ligands) in methylene chloride, a remarkable reduction of particle size was achieved. In higher boiling solvent (toluene), where the indium nanoparticles at reflux temperature are probably melted, it does not allow the best result, and less monodispersity is achieved. We employed different surface active ligands (amine, phosphine, and mixed ligands) to passivate these indium nanoparticles. The temporal evolution of the surface plasmon of indium nanoparticles was monitored by in situ UV-vis spectroscopy, and particles were characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD). The merits of this synthesis procedure are the use of bulk indium as starting material, tuning the particle size in low boiling point solvent, particle size adjustment with the choice of ligand, and a possible scale up.

Metallic indium spheres by the anaerobic ethanol oxidation of indium oxide

“…Reducing metals of Zn, Sn, and Na have values of 9.4, 7.3, and 5.1 eV, respectively [6]. Metallic In particles or nanoparticles (NPs) are prepared using several methods, which include a reduction method [7], decomposition of an In complex [4], and vapor/sputter deposition method [8,9]. Recently, Dorn et al used [11].…”

“…Zhang et al used a solvothermal method at 120°C and obtained metallic In hollow spheres and nanotubes using InCl 3 and Zn powder in ethanol [15]. For size reduction or morphology changes [8,9,[16][17][18], In nanowires/whiskers were synthesized by chemical vapor deposition using In metal in a Ar atmosphere [16]. Spherical In NPs were also prepared by applying ultrasound irradiation to molten bulk In metal [17,18].…”

Preparation and nonlinear optical properties of indium nanocrystals in sodium borosilicate glass by the sol–gel route

“…All the diffraction peaks can be indexed as the tetragonal indium with lattice constants a = 3.251 Å and c = 4.945 Å , which are consistent with the values in the standard card (JCPDS No. 05-0642) [12]. Further, no peaks for any impurities such as In 2 O 3 , or other phases are observed in the patterns which further confirm the crystalline and pure phase of the tetragonal indium.…”

“…Although, most of the available literature focuses on nanocrystals of noble and transition metal, there are very few reports on the nanocrystals of other metals including indium. Indium is widely used in the field of electronics (for single electron transistor) [8], electronic switches [9], as a component in low melting solders [10], solid-state lubricants [11], bio-nanotechnology (as tags for detection of DNA hybridization) and as printing nanoparticle building blocks in nanoxerography [12,13].…”

Electrochemical Synthesis of Indium(0) Nanoparticles in Haloindate(III) Ionic Liquids

“…[4] However, only few papers describe the synthesis of indium(0) nanoparticles. [5] The published physical methods require either specialised techniques (e.g., sonication, [6] laser ablation, [7] sputter deposition, [8] or solvated metal atom dispersion with subsequent digestive ripening [1] ) or at least high temperatures (dispersing molten indium in paraffin oil, > 180 8C [9] ). The chemical methods involve reduction by strong reducing agents, for example, metallic sodium [10] or sodium tetrahydroborate(III), [11] and there have only been a few reported cases of catalysis with indium(0) nanoparticles.…”