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sp 2/sp 3 bonding ratio dependence of the band-gap in graphene oxide
, Article European Physical Journal B ; Volume 92, Issue 4 , 2019 ; 14346028 (ISSN) ; Akbari, I ; Ebrahimi, M. R ; Sharif University of Technology
Springer Heidelberg
2019
Abstract
Abstract: Although the band-gap in pure graphene is zero, the oxygenated graphene could have a considerable band-gap. The D/G peak intensity ratio is known as a measure of the size of sp3∕sp2 domains in graphene oxide (GO) sheets and determines the band-gap in GO sheets. Characterization results showed that the photoluminescence (PL) spectra of GO suspensions has a peak at ~604 nm and also the I(D)/I(G) intensity ratio of GO suspensions is 1.73. After reduction, a redshift appeared at PL spectrum (at 650 nm) and the I(D)/I(G) intensity ratio decrease to 1.26. Our results showed that the band-gap in GO is related to the I(D)/I(G) intensity ratio of GO suspensions and offers a mechanism for...
Rapid and efficient synthesis of colloidal gold nanoparticles by arc discharge method
, Article Applied Physics A: Materials Science and Processing ; Volume 96, Issue 2 , 2009 , Pages 423-428 ; 09478396 (ISSN) ; Iraji zad, A ; Mahdavi, M ; Ahadian, M. M ; Hormozi nezhad, M. R ; Sharif University of Technology
2009
Abstract
We report a simple, inexpensive and one-step synthesis route of colloidal gold nanoparticles using arc discharge between titanium electrodes in HAuCl 4 solution achieving long-time stability. Gold nanoparticles of 8 nm diameter were formed during reduction of HAuCl4 in the plasma discharge zone. The resulting nanoparticles were characterized using UV-Vis spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Optical absorption spectroscopy of as prepared samples at 15 A arc current in HAuCl4 solution shows a surface plasmon resonance around 550 nm. It was found that sodium citrate acts as a stabilizer and surface capping agent of the colloidal...