Laser-induced manipulation of the size and shape of small metal particles: Towards monodisperse clusters on surfaces

Abstract

A novel experimental technique is presented for post growth narrowing of the size distribution of metal nanoparticles on dielectric substrates. In order to demonstrate the potential of the method, oblate Ag clusters with mean radii of R = 6 nm and broad size distributions were prepared under ultrahigh vacuum conditions on quartz substrates. Narrowing of the width of their size distribution was accomplished by irradiation with short laser pulses. The laser light excites plasmons in the particles, the frequency of which depends on the size and shape of the clusters. By choosing the light frequency such that only the smallest and the largest particles selectively absorb light, evaporate atoms and shrink in size, the size distribution was narrowed by 40%. A scenario for producing monodisperse particles is discussed.PACS. 61.46.+w Clusters, nanoparticles, and nanocrystalline materials -68.55.-a Thin film structure and morphology -78.20.e Optical properties of bulk materials and thin films -78.40.Kc Metals, semimetals, and alloys -81.40.Tv Optical and dielectric properties

Reversible conversion of nanoparticles of metallic silver and silver oxide in ultrathin TiO2 films: a chemical transformation in nano-space

“…Recently, Stietz et al showed that the size distribution of Ag nanoparticles was narrowed by 40% by choosing the laser pulse frequency such that only the smallest and the largest particles selectively absorbed light. 10 El-Sayed et al reported shape changes of colloidal gold nanorods by femtosecond and nanosecond laser pulses. 11 More recently, Mirkin et al showed that silver nanospheres were converted to nanoprisms by conventional fluorescent light.…”

A comparative study of laser‐ and electric‐field‐induced effects on the crystallinity, surface morphology and plasmon resonance of indium and gold thin films

“…It should be noted that narrowing of the width of the particle‐size distribution has previously been demonstrated by irradiation of metal surfaces with short laser pulses 42. The mechanism proposed is that the photon beam excites plasmons in the metal particles, the frequency of which depends on the size and shape of the clusters.…”

Synthetic Approaches to Metallic Nanomaterials

“…They were able to vary the particle size of colloidal Pd between 0.55 and 4.5 nm using the salt reduction method. Size control has also been reported for the sonochemical decomposition method and c-radiolysis [173,194,195]. According to the literature on the process of nucleation and particle growth, the essential factors which control the particle size are the strength of the metal-metal bond [48], the molar ratio of metal salt, colloidal stabilizer, reduction agent [1,128,135,[176][177][178][179][180][181][182][183][184][185][186][187][188][189][190][191][192][193], the extent of conversion or the reaction time [128], the temperature applied [1,177,189], and the pressure [177].…”