Present work proposes green synthesis of reduced graphene oxide using lemon peel extract(vitamin-c) and its application as an electrochemical nonenzymatic human serum glucose sensor. Improved modified Hummer's method was preferred for the preparation of graphene oxide. X-ray diffraction (XRD), Ultraviolet-visible absorption spectroscopy (UV-Vis) and X-ray photon spectroscopy (XPS) analysis revealed the successful reduction of Graphene oxide (GO) using lemon peel extract. Field emission scanning electron microscopy (FESEM), Fourier transform infra-red spectroscopy (FTIR) and Raman spectroscopy supports the formation of reduced graphene oxide (rGO) nanosheets. The proposed glucose sensor exhibits high sensitivity of 1402 μA•cm −2 mM −1 (S/N=3) along with correlation coefficient of 0.9887 and low detection limit of 0.011 μM. The sensor has detected glucose with RSD of 1.99% in human blood serum. The measured values are well agreed with the values obtained using professional glucose sensor used in hospitals.

Electronic states of PrCoO 3 are studied using X-ray photoemission spectroscopy. Pr 3d 5/2 core level and valence band (VB) were recorded using Mg K α source. The core level spectrum shows that the 3d 5/2 level is split into two components of multiplicity 4 and 2, respectively due to coupling of the spin states of the hole in 3d 5/2 with Pr 4f holes spin state. The observed splitting is 4.5 eV. The VB spectrum is interpreted using density of states. Thus in the Zaanen, Sawatzky, and Allen scheme PrCoO 3 can be considered as charge transfer insulator. The charge transfer energy ∆ can be obtained using LDA DOS calculations and the Coulomb-exchange energy U′ from LDA+U. The explicit values for PrCoO 3 are ∆ = 3.9 eV and U′ = 5.5 eV; the crystal field splitting and 3d bandwidth of Co ions are also found to be 2.8 and 1.8 eV, respectively. 2

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Thin films of S n O^ (0 < x < 1) were deposited on Corning glass and alumina substrates by employing a pulsed laser evaporation (PLE) technique. The microstructural features of the films were probed with Sn"9 conversion electron Mossbauer spectroscopy (CEMS) whereas the structural characteristics were identified by using low-angle x-ray diifraction measurements. The electrical and optical properties have also been studied. It is shown that films with conductivity of 3 X 102 (ohm • cm) ~' and transmission of 90% can be obtained by appropriate postannealing of the as-deposited films in air and vacuum. The energy gap of this nearly stoichiometric single-phase SnO2 film was found to be 3.5 eV and spectroscopic ellipsometry measurements indicated the refractive index to be typically bet ween 1.8-1.9 over the wavelength range of400-800 nm.