Regular Article

sp²/sp³ bonding ratio dependence of the band-gap in graphene oxide

¹ Department of Physics, Sharif University of Technology, P.O. Box 11155-9161, Tehran, Iran
² Department of Physics, Yasuj University, P.O. Box 75918-74934, Yasuj, Iran

^a e-mail: ebrahimakbari@alum.sharif.edu

Received: 15 November 2018
Received in final form: 10 January 2019
Published online: 3 April 2019

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 measuring the band gap according to Raman spectra. Moreover, GO is fluorescent over a broad range of wavelengths and can be used in the biological application.