Selective band gap manipulation of graphene oxide by its reduction with mild reagents

Abstract

Selective band gap manipulation of graphene oxide by its reduction with mild reagents, Carbon (2015), doi: http://dx. ABSTRACTGraphene oxide (GO) can be used as an electron acceptor for polymeric solar cells but still band gap matching for electron donor and acceptor demands more study. The generation of the exciton in such materials is intimately related to the optical band gap. However, exciton dissociation is related to transport band gap that controls the device performance, particularly the open circuit voltage and short circuit current. Therefore, the modulation of the optical gap is useful because it results into tuning of the transport gap. The interest of the present work is to study the reduction of graphene oxide (GO) at room temperature, using environmental friendly reagents like glucose, fructose and ascorbic acid for the modulation of a band gap. It has been found that glucose and fructose function effectively only in presence of NH 4 OH. Although ascorbic acid can reduce GO alone, NH 4 OH speeds up the reaction. The optical band gap of GO can be reduced and tuned effectively from 2.7eV to 1.15eV.

Graphene Oxide as An Efficient Photocatalyst For Photocatalytic Reduction of CO2 Into Solar Fuel

“…Optical band gap of GO calculated by Kubelka-Munk function using Tauc plot was 1.3 eV as shown in Figure 2(b). Bandgap energy of GO depends on oxygen function groups density and high oxygen density will generate larger bandgap [43]. Low bandgap of 1.3 eV suggest that GO should produce high yield of solar fuel.…”

Graphene Derivatives: Controlled Properties, Nanocomposites, and Energy Harvesting Applications

“…This technique allows to specify the C]Ca n dC dC, which is 21.3% and 18.73%. Also for the C]O]Ca n d C]OH is 52.03%, CdO is 3.54%, and for COOH 4.4% [2]. Graphene Derivatives: Controlled Properties, Nanocomposites, and Energy Harvesting Applications http://dx.doi.org/10.5772/67474 81…”

“…However, due its toxicity, it is also preferable to use harmless reducing agents such as fructose, glucose, and ascorbic acid in basic medium, obtaining values of 2.7-1.1 eV [2,16]. The XPS analysis, plays a key role for the oxygen quantification, is shown in Figure 6.…”

“…In this chapter, various approaches are explored to develop materials with a possible application in OPVs, based on modified GO into the active layer. It is well known that GO has a band gap of 3.1 eV, which can be further modulated by chemical reduction reactions [2]. The Figure 1.…”

“…Therefore, GO is a highly hydrophilic molecule and, more important for electronics and energy-harvesting applications, this process provides a band gap (E g ). For example, the energy difference between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) in the resulting complete oxidized material is around 3 eV [2], which is also directly related to the carbon-oxygen ratio [3]. Oxidation reactions include strong acid attacks with H 2 SO 4 , HNO 3 ,H 2 O 2 , KMnO 4 ,o ra mixture of them, being one of the most used by the Hummers method [4].…”