Open AccessAn investigation of the stirring duration effect on synthesized graphene oxide for dye-sensitized solar cells
Author(s) -
Xin Hui Yau,
Foo Wah Low,
Cheng Seong Khe,
Chin Wei Lai,
Sieh Kiong Tiong,
Nowshad Amin
Publication year - 2020
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0228322
Subject(s) - fourier transform infrared spectroscopy , raman spectroscopy , materials science , graphene , analytical chemistry (journal) , oxide , dielectric spectroscopy , spectroscopy , scanning electron microscope , dye sensitized solar cell , titanium dioxide , nanocomposite , nuclear chemistry , chemical engineering , electrochemistry , chemistry , nanotechnology , electrode , optics , physics , chromatography , quantum mechanics , composite material , electrolyte , engineering , metallurgy
This study investigates the effects of stirring duration on the synthesis of graphene oxide (GO) using an improved Hummers’ method. Various samples are examined under different stirring durations (20, 40, 60, 72, and 80 h). The synthesized GO samples are evaluated through X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), and Raman spectroscopy. The GO sample with 72 h stirring duration (GO72) has the highest d-spacing in the XRD results, highest atomic percentage of oxygen in EDX (49.57%), highest intensity of oxygen functional group in FTIR spectra, and highest intensity ratio in Raman analysis (I D /I G = 0.756). Results show that GO72 with continuous stirring has the highest degree of oxidation among other samples. Electrochemical impedance spectroscopy analysis shows that GO72–titanium dioxide (TiO 2 ) exhibits smaller charge transfer resistance and higher electron lifetime compared with the TiO 2 -based photoanode. The GO72 sample incorporating TiO 2 nanocomposites achieves 6.25% photoconversion efficiency, indicating an increase of more than twice than that of the mesoporous TiO 2 sample. This condition is fully attributed to the efficient absorption rate of nanocomposites and the reduction of the recombination rate of TiO 2 by GO in dye-sensitized solar cells.