SYNTHESIS AND CHARACTERIZATION OF GRAPHENE OXIDE THIN FILM AS A STARTING MATERIAL FOR GRAPHENE-BASED TRANSPARENT CONDUCTIVE LAYERS

• Main Author: RAHMAWATI NIM:20515022, TRIANNISA
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/31363
• Institution: Institut Teknologi Bandung

Transparent conductive film is an optically transparent material which can conduct electrical current. The benefit of this film has been widely used as a component of modern devices, such as touch screens, solar cells, liquid crystal displays (LCDs), organic light-emitting diodes (OLEDs), and thin film light-emitting diodes (TF LEDs). One of the conductive transparent film materials is indium tin oxide (ITO). The application of ITO as a conductive film has been widely used because ITO has high transparency and excellent electrical conductivity. However, ITO has drawbacks, including expensive price of raw materials due to its availability in nature, therefore it is important to find the alternative materials that can replace ITO. Graphene, an allotrope of carbon is the main material currently being studied as a substitute of ITO. The advantages of graphene are its elasticity, its transparency due to its thickness, high heat and electrical conductivity than other metals. The purpose of this study was to determine the condition that can produce high quality graphene oxide (GO), and to determine its dispersion stability in various solvents. The principle of graphene synthesis is started by the oxidation of graphite into graphite oxide, then followed by mechanical exfoliation through dispersing in a particular solvent with the help of ultrasonic wave. Chemical method was based on modified Hummers. Hummers method was modified by replacing KMnO4 with ammonium persulfate (APS), and burning graphite to reduce the amorphous part. Furthermore, film dope solution was made by mixing poly(methyl methacrylate) with GO (PMMA/GO) in various solvents. GO was dispersed in water, then spread and dried on gold surface prior to Raman characterization. Raman spectroscopy of GO was characterized by three distinct peaks, namely D band at 1349,0 cm-1, G band at 1583,0 cm-1, and 2D band at 2695,5 cm-1. Based on Raman spectra, this method produced GO that consists of 3 layers of graphene in average. Moreover, particle size analyzer (PSA) measurements showed that produced GO has a wide range of size from 27,1 to 147,2 nm with the peak distribution at 29,3 nm. Two absorption peaks of GO were observed by UV-Vis spectroscopy at 6,49 eV and 4,68 eV, which correspond to ?* ? ? for C-C aromatic bond and ?* ? n for the C=O bond, respectively. Meanwhile, PMMA/GO films were made by dispersing 1 mg/mL of GO in NMP, acetone, and toluene with PMMA from 1 to 5 wt. %. Solution was then deposited on microscope slides and ITO glasses using spin coating technique. This solvents was used based on the stability test of GO dispersion in 12 types of solvents for 1 month. Optical measurements were performed by measuring the % transmittance of the deposited film using UV-Vis spectroscopy. The measurement of transmission data is in a good agreement with the white percentage data from the film surface observation using an optical microscope after proceed using ImageJ software.