New technological application in the preparation of Ag-containing graphene oxide structure: cryogenic coating method

Abstract

In this study, graphene oxide (GO) structure was doped with metallic silver (Ag) atoms in vacuum environment (10–6 Torr) at 200 K. GO and GO/Ag samples were analyzed using X-ray diffractometry (XRD), scanning electron microscope (SEM), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy and optical and electrochemical impedance spectroscopy (EIS). XRD patterns showed that the samples investigated grew in the hexagonal structure (2θ = 9.4°). However, reflection peaks originating from Ag were observed in the XRD patterns of GO/Ag samples. SEM images showed that there was an increase in grain size and layer number in the GO structure with Ag doping. Bond vibrations originating from carbon, oxygen and hydrogen atoms were observed from the FTIR spectra. In addition, ID/IG ratios of GO and GO/Ag samples were calculated and found to be 0.89 and 0.82, respectively. From optical measurements, it was seen that surface plasmon resonance (SPR) event occurred at 430 nm wavelength in GO/Ag samples. Electrical properties of samples were examined under different wavelength beams (room, 366 nm and 450 nm) during measurement using EIS method (“Room” refers to the normal lighting in the room environment.). The lowest charge transfer resistance was observed in GO/Ag sample illuminated with 450 nm wavelength. Then, solutions containing GO and GO/Ag were prepared and two different diode structures were produced by spraying them onto p-Si crystal surface by chemical sputtering method. Characteristics of diodes in dark and light environments (100 mW/cm2) were examined, and it was seen that diode-containing Ag exhibited better photovoltaic values.