الفهرس 
Introduction and Theoretical BackgroundOnly 14 pages are availabe for public view
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Abstract
In this thesis, rGO is synthesized using modified Hummer method and confirmed by EDX, XRD and high resolution TEM. Then nanocrystalline films of xrGO (x1)nH2OV2O5 (0≤ x ≥ 0.35) are then prepared by the sol–gel method and applied to glass substrate by dip-coating technique. The structural, optical and electrical properties of reduced graphene oxide (rGO) doped vanadium pentoxide rGOxV2O5nH2O nanocrystalline films has been studied. XRD measurements showed good fit with known card JCPDS 40-1296 of vanadium pentoxide with nanocrystals structure oriented toward the c-axis. The line of (002) in XRD patterns becomes weaker by the addition of rGO and nearly missed at higher concentrations indicating the intercalation of rGO within the vanadium layers. The measured average particle size decrease with increasing rGO content from 4.86 nm to 3.17 nm. Optical properties have been studied by measuring the absorption, reflectance and transmittance of the prepared samples using double-beam UV-Visible spectrophotometer. The optical constants such as refractive index n, extinction coefficient k, real and imaginary dielectric constants, absorption coefficient α, and optical band gap Eop of the nanocrystalline films have been evaluated. The absorption coefficient decreases with increasing rGO content, which may be attributed to the decrease in lattice distortion owing to rGO content due to the decrease of particle size as indicated in the XRD and HRTEM. Optical measurements revealed that there are two different optical gaps Eop1 and Eop2. It is found that the optical gap Eop1 decreases xix with the increase of rGO content, while the optical gap Eop2 increases with the increase of rGO content. The carrier’s concentration (N) as well as the effective mass (m+ ) are calculated assuming hydrogen-like model. The activation energy is calculated and found to be increasing from 0.157eV to 0.181eV as rGO increases from 0 to 0.35mol%. The vanadium ions concentration N is calculated and found to be increasing from 1.11 X1022 cm-3 to 1.38 X1022 cm-3with the addition of rGO, while the spacing of vanadium ions R decreases from 0.448nm to 0.417nm. The hopping carrier mobility (μ) and carrier density (Ne) of the prepared samples are also calculated at fixed temperature. Greaves model for variable range hopping is studied for the prepared samples. The prepared samples of rGOxV2O5nH2O nanocrystalline films are studied as a photo-stabilizer utilizing the high absorption in the range 200 to 500 nm. The study shows that reduced graphene oxide rGO is proven to be excellent inhibitor for the photo-degradation process in the range from 300 to 1100 nm and in turn, is a promising application as a photo-stabilizer for solar cells and optical sensors.