Growth and characterization of branched gold nanoparticles on surfaces

Download

index.pdf

Date

2014

Author

Evcimen, Nimet İlkem

Metadata

Show full item record

Item Usage Stats

161
views

86
downloads

Branched gold nanoparticles, having sharp edges and tips, provide very high sensitivity to local changes in the dielectric environment, as well as large enhancements of the electric field around the nanoparticles. This makes them very attractive for the applications where special optical properties are needed such as sensing, therapeutic treatments and photovoltaic devices. Nanostructures are needed to be stabilized on some type of support for most of these applications.. This can be achieved either by dispersing synthesized nanoparticles onto the surfaces or by directly synthesizing them on the surface. Second approach can be more practical as it is eliminating the extra step of nanoparticle dispersion by methods such as spin coating or drop casting. In this study, branched Au nanoparticles were synthesized on surfaces of three different supports (glass, ITO, Si-wafer). Parametric study was performed to investigate the effect of reactant concentrations, seed type and pH of the growth media on the quality of products. Optimum conditions were determined for synthesizing nanostructures in high yield and structural purity. Characterization of nanostructures was done by detailed analysis via scanning electron microscope (SEM), energy dispersive X-Ray (EDX) and X-Ray Diffraction (XRD) methods. The analyses showed that all of the nanostructures synthesized at optimum conditions have branched morphologies with sizes of ca. 450 nm and they are well dispersed on the support surface.

Subject Keywords

Nanoparticles., Anisotropy., Gold., Silicon.

URI

http://etd.lib.metu.edu.tr/upload/12618334/index.pdf
https://hdl.handle.net/11511/24353

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Growth and morphological characterization of intrinsic hydrogenated amorphous silicon thin film for a-Si:H/c-Si heterojunction solar cells Pehlivan, Özlem; Tomak, Mehmet; Kodolbaş, Alp Osman; Department of Physics (2013) Passivation of the crystalline silicon (c-Si) wafer surface and decreasing the number of interface defects are basic requirements for development of high efficiency a-Si:H/c-Si heterojunction solar cells. Surface passivation is generally achieved by development of detailed silicon wafer cleaning processes and the optimization of PECVD parameters for the deposition of intrinsic hydrogenated amorphous silicon layer. a-Si:H layers are grown in UHV-PECVD system. Solar cells were deposited on the p type Cz-silic...
Formation and characterization of infrared absorbing copper oxide surfaces Arslan, Burcu; Erdogan, Metehan; Karakaya, İshak (2017-04-30) Copper oxide formation has been investigated to combine the advantages of producing different size and shapes of coatings that possess good light absorbing properties. An aqueous blackening solution was investigated and optimum composition was found as 2.5 M NaOH and 0.225 M NaClO to form velvet copper oxide films. A two-step oxidation mechanism was proposed for the blackening process by carefully examining the experimental results. Formation of Cu2O was observed until the entire copper surface was covered ...
Structural characterization of intrinsic a-Si:H thin films for silicon heterojunction solar cells Pehlivan, O.; Yilmaz, O.; Kodolbas, A. O.; Duygulu, O.; Tomak, Mehmet (2013-01-01) We have utilized ex-situ spectroscopic ellipsometry and HRTEM to characterize the optical and structural properties of intrinsic a-Si:H thin layer that plays a key role for the improvement of the open circuit voltage in silicon heterojunction solar cells. Intrinsic a-Si:H films were deposited on (100) p-type CZ silicon wafers by using Plasma Enhanced Chemical Vapor Deposition (PECVD) technique at 225 degrees C substrate temperature and deposition time ranges from 15 s to 1800 s. Observed changes in the imag...
Efficient Light Trapping in Inverted Nanopyramid Thin Crystalline Silicon Membranes for Solar Cell Applications MAVROKEFALOS, Anastassios; HAN, Sang Eon; Yerci, Selçuk; Branham, Matthew S.; CHEN, Gang (2012-06-01) Thin-film crystalline silicon (c-Si) solar cells with light-trapping structures can enhance light absorption within the semiconductor absorber layer and reduce material usage. Here we demonstrate that an inverted nanopyramid light-trapping scheme for c-Si thin films, fabricated at wafer scale via a low-cost wet etching process, significantly enhances absorption within the c-Si layer. A broadband enhancement in absorptance that approaches the Yablo-novitch limit (Yablo-novitch, E. J. Opt. Soc. Am. 1987, 72, ...
Biosensors Based on Nano-Gold/Zeolite-Modified Ion Selective Field-Effect Transistors for Creatinine Detection Kasap, Berna Ozansoy; Marchenko, Svitlana V.; Soldatkin, Oleksandr O.; Dzyadevych, Sergei V.; Akata Kurç, Burcu (2017-03-02) The combination of advantages of using zeolites and gold nanoparticles were aimed to be used for the first time to improve the characteristic properties of ion selective field-effect transistor (ISFET)-based creatinine biosensors. The biosensors with covalently cross-linked creatinine deiminase using glutaraldehyde (GA) were used as a control group, and the effect of different types of zeolites on biosensor responses was investigated in detail by using silicalite, zeolite beta (BEA), nano-sized zeolite beta...

Citation Formats

N. İ. Evcimen, “Growth and characterization of branched gold nanoparticles on surfaces,” M.S. - Master of Science, Middle East Technical University, 2014.