X-ray-induced production of gold nanoparticles on a SiO2/Si system and in a poly(methyl methacrylate) matrix

Karadas, F
Ertaş, Gülay
Ozkaraoglu, E
Suzer, S
Prolonged exposure to X-rays of HAuCl4 deposited from an aqueous solution onto a SiO2/Si substrate or into a poly(methyl methacrylate) (PMMA) matrix induces reduction of the Au3+ ions to Au-0 and subsequent nucleation to gold nanoclusters as recorded by X-ray photoelectron spectroscopy. The corresponding major oxidation product is determined as chlorine {HAuCl4(ads) + X-rays --> Au(ads) + (3/2)Cl-2(ads) + HCl(ads)}, which is initially adsorbed onto the surface but eventually diffuses out of the system into the vacuum. The reduced gold atoms aggregate (three-dimensionally) into gold nanoclusters as evidenced by the variation in the binding energy during X-ray exposure, which starts as 1.3 eV but approaches a value that is 0.5 eV higher than that of the bulk gold. The disappearance of the oxidation product (Cl2p signal) and the growth of the nanoclusters (related to the measured binding energy difference between the Si2p of the oxide and Au4f of the reduced gold) exhibit first-order kinetics which is approximately 3 times slower than the reduction of Au3+, indicating that both of the former processes are diffusion controlled. Similarly, gold ions incorporated into PMMA can also be reduced and aggregated to gold nanoclusters using 254 nm deep UV irradiation in air evidenced by UV-vis-NIR absorption spectrocopy.


X-ray photoelectron spectroscopic characterization of Au collected with atom trapping on silica for atomic absorption spectrometry
Suzer, S; Ertas, N; Kumser, S; Ataman, Osman Yavuz (1997-10-01)
The nature of analyte species collected on a cooled silica tube for atom-trapping atomic absorption spectrometric determination was investigated with the use of X-ray photoelctron spectroscopy (XPS). An XPS spectrum of gold deposited on atom-trapping silica tubes reveals a Au 4f(7/2) peak with a binding energy of 84.8 (+/-0.2) eV, which falls in the middle of the binding energies corresponding to zerovalent Au(0) at 84.0 eV and that of monovalent Au(I) at 85.2 eV, The corresponding energy for Au vapor depos...
2-D analysis of Ge implanted SiO(2) surfaces by laser-induced breakdown spectroscopy
Yalcin, Serife; Oerer, Sabiha; Turan, Raşit (Elsevier BV, 2008-10-01)
2-D elemental distribution of Ge in silicon oxide substrates with differing implantation doses of between 3x10(16) cm(-2) and 1.5x10(17) cm(-2) has been investigated by Laser-induced Breakdown Spectroscopy (LIBS). Spectral emission intensity has been optimized with respect to time, crater size, ablation depth and laser energy. Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) coupled with Energy-Dispersive X-Ray Spectroscopy (EDX) have been utilized to obtain crater depth, morphology and ...
X-ray photoelectron spectroscopy for resistance-capacitance measurements of surface structures
Ertaş, Gülay; Atalar, A; Suzer, S (2005-05-02)
In x-ray photoemission measurements, differential charging causes the measured binding energy difference between the Si 2p of the oxide and the silicon substrate to vary nonlinearly as a function of the applied external do voltage stress, which controls the low-energy electrons going into and out of the sample. This nonlinear variation is similar to the system where a gold metal strip is connected to the same voltage stress through an external 10 Mohm series resistor and determined again by x-ray photoelect...
X-ray photoelectron spectroscopic investigation of conducting polymer blends
Suzer, S; Toppare, Levent Kamil; Hallam, KR; Allen, GC (1996-06-01)
Electrochemically prepared films of conducting polymers of polypyrrole and polythiophene and their blends with polyamide have been investigated by X-ray photoelectron spectroscopy. In the N1s region of the spectra of films containing polypyrrole the peak corresponding to N+ at 402.0 eV is separated from that of neutral N. The intensity of the N+ peak can be correlated with the electrical conductivity of the films and the spectroscopically derived ratio of F/N+ is close to 4 indicating that one BF4- dopant i...
X-ray investigation of sintered cadmium doped hydroxyapatites
Evis, Zafer; USTA, Metin; AKTUĞ, SALİM LEVENT (2013-04-01)
Pure and cadmium (Cd) doped hydroxyapatites (HA, Ca-10(PO4)(6)(OH)(2)) were synthesized by a precipitation method from aqueous solutions of Ca(NO3)(2)4 center dot H2O for the former and Cd(NO3)(2)4 center dot H2O for the latter, by using (NH4)(2)HPO4 as the phosphate source, while pH was kept in the range of 11-12. The effect of incorporation of Cd2+ ions into the structure of HA was investigated after the air sintering at 1100 degrees C for 1 h. The results indicate that Cd2+ addition into HA yields nearly...
Citation Formats
F. Karadas, G. Ertaş, E. Ozkaraoglu, and S. Suzer, “X-ray-induced production of gold nanoparticles on a SiO2/Si system and in a poly(methyl methacrylate) matrix,” LANGMUIR, pp. 437–442, 2005, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/41815.