Journal of Nanoanalysis
Volume:2 Issue: 2, Aug 2015

A new strategy for enhancing the efficiency of TiO2 dye-sensitized solar cells (DSSCs) by doping foreign ion into TiO2 lattice via sol-gel process is reported. DSSCs are based on a semiconductor (i.e., TiO2), formed between a photo-sensitized anode and an electrolyte. In order to reach high conversion efficiency, it is important to increase the electron injection and optical absorption. One promising solution to increase the electron injection is to decrease the large band gap of TiO2 by doping a foreign ion into TiO2 lattice. In the present work, Ag- doped TiO2 nanopowders and thin films with different Ag:Ti ratios are reported. The effect of dopant WT% on photovoltaic performance of dye-sensitized solar cells were studied. The powders were synthesized via aqueous sol–gel route, followed by annealing at 500°C for 4hr. X-ray diffraction and Field emission scanning electron microscope (FE-SEM) analyses revealed that the synthesized samples had uniform grains in nanometer range. It was found that, 0.05 WT. % Ag-doped TiO2 DSSC (i.e., DSSC number 2) had the highest power conversion efficiency of 2.4%, short current density of 5.65 mA/cm2 and open circuit voltage of 761 mV. This can be related to achievement of an optimum condition balance among the electron injection, light scattering effect and dye sensitization. The applied method exhibited superior potential for synthesis of Ag-doped TiO2 nanopowders and films to utilize as DSSCs.

This work investigates the potential of magnetic Fe3O4 nanoparticles as an adsorbent for separation and preconcentration of trace amounts of mefenamic acid in aquatic and biological samples, prior to spectrophotometric determination. The magnetic iron oxide nanoparticles (MIONs) were synthesized by mixing of ferrous and ferric chlorides. The possible parameters affecting the enrichment were optimized. It is shown that the novel magnetic nano-adsorbent is quite efficient for fast adsorption of mefenamic acid in pH =7.0. Various parameters affecting the adsorption of mefenamic acid on MIONs, such as pH of solution, desorbing reagent, adsorption isotherms, sample volume, amount of adsorbent and matrix effects, have been investigated. The calibration graph for the determination of mefenamic acid was linear in the range of 1.25-7.25 ng mL−1. The limit of detection, defined as LOD= 3Sb/m was 0.5 ng mL−1 (n=3) of mefenamic acid and the relative standard deviation was 3.6%. The preconcentration factor of 150 was achieved in this method. The proposed procedure has been successfully applied to the determination of mefenamic acid in biological samples such as human plasma and dextrose saline.

At this short review, different chemical production of 3D graphene biocatalysts and developing of its characters by new substituted for using in enzymatic fuel cells are investigated. Also, the current ways of production of 3D Graphene Biocatalysts, different types of substitutes, the best methods for having the highest efficiency, the physical, chemical and biological characters of new biocatalyst and finally, the advantages and disadvantages of this new biocatalyst are reviewed.