Engineering tunable conductivity, p-n junction and light-harvesting semi-conductivity of graphene oxide by fixing reduction mood only

Abstract

Modulated electron conductivity (EC), p-n junction behavior and light-harvesting semiconductivity in reduced graphene oxide (rGO) is observed. Pristine graphene oxide (GO) film on borosilicate glass was reduced by ascorbic acid (AA), Glucose (GC), hydrogen iodide (HI), thiourea (TU), hydrazine solution (HS) and hydrazine vapor (HV) to obtain respective rGOAA, rGOGC, rGOHI, rGOTU, rGOHS and rGOHV films. The morphologies of the films were studied by SEM image and PXRD spectra. The functional groups were studied by IR, Raman and XPS spectra. Except rGOHV, the samples exhibited tunable electron conduction behavior (EC) following the trend as rGOHS (1.1 × 10−1 mA/V) > rGOTU (4.4 × 10−3 mA/V) > rGOGC (1.5 × 10−3 mA/V) > rGOHI (8.9 × 10−4 mA/V) > rGOAA (2.6 × 10−4 mA/V). However, rGOHV exhibited p-n junction behavior with the knee point at 0.66 and -0.62 V for the forward and reverse bias, respectively. rGOHS and rGOHV could exhibit photocatalytic activity due to the presence of doped N. The water-splitting efficiency of rGOHS and rGOHV are 2.38 and 3.75 μmol/hg, respectively, whereas respective dye degradation efficiencies are 84.16 and 92.48%. TGA data confirms that rGOHV sustains with some water adsorbing capacity that can aid the hydrodynamics. Further, the hydrodynamics within rGO film was confirmed from hydronium ion conductivity.