Sharif Digital Repository

In this study a novel symmetrical metal-free organic dye for applications in dye-sensitized solar cells (DSSCs) was synthesized. This dye (D) was designed with A-π-D-π-A framework and synthesized with 9,9-dioctylfluorene as electron donor, phenylene as π-spacer and cyanoacetic acid as electron acceptor. The chemical structure of product was determined using UV-Vis, FT-IR, CNMR, HNMR spectroscopy techniques. The presence of a phenylene π-bridge between the donor and the acceptor units and the di-anchoring moieties in this structure led to enhancement of conjugation lengths and molar extinction coefficient (ε) that is promising for further improvement of the conversion efficiency of DSSCs.... 

In this study a novel symmetrical metal-free organic dye for applications in dye-sensitized solar cells (DSSCs) was synthesized. This dye (D) was designed with A-π-D-π-A framework and synthesized with 9,9-dioctylfluorene as electron donor, phenylene as π-spacer and cyanoacetic acid as electron acceptor. The chemical structure of product was determined using UV-Vis, FT-IR, CNMR, HNMR spectroscopy techniques. The presence of a phenylene π-bridge between the donor and the acceptor units and the di-anchoring moieties in this structure led to enhancement of conjugation lengths and molar extinction coefficient (ε) that is promising for further improvement of the conversion efficiency of DSSCs  

A series of bithiazole-based dye sensitizers have been designed by employing various electron-rich moieties as π-spacer, which are based on the reported experimentally synthesized dye T-BT, to shed a light on the impact of both the nature and position of electron-rich moiety on the efficiency of dyes in DSSCs. To evaluate the efficiency of these dyes, various key parameters associated with overall conversion efficiency (η), including electronic and optical properties of free dyes are calculated, based on the computational methods. Besides, the dye/TiO2 structures have been taken into account to investigate the interfacial features of the dye sensitizers adsorbed on TiO2 semiconductor and... 

One of the appealing usages of metal–organic frameworks is their application in manufacturing of metal oxide and metal oxide nanocomposites. In the present study, we used zeolitic imidazolate framework (ZIF-8) as precursor to prepare a new Ag/C/ZnO catalyst. The as-prepared samples were characterized using X-ray diffraction, Fourier-transform infrared, scanning electron microscopy and transmission electron microscopy analysis. Improved catalytic performance of as-prepared Ag/C/ZnO was confirmed by reduction of organic pollutants including p-nitrophenol, methylene blue and rhodamine-B in the presence of NaBH 4 in aqueous media. The synergistic effect between Ag and ZnO was proposed as the... 

A series of experimentally synthesized metal free organic dyes based on the 2-Cyano-3-(5-(5'-(4-(diphenylamino)phenyl)-4,4'-dihexyl-2,2'-bithiazol-5-yl)thiophen-2-yl)acrylic acid (dye 1) were investigated, based on computational methods to shed light on how a tiny difference in π-linker of sensitizer, C[tbnd]C and thiophene moiety as the additional π spacer group in dyes 2 and 3 respectively, has a significant impact on the short-circuit photocurrent densities (JSC) in Dye-sensitized solar cells (DSSCs). Although dyes 2 and 3 have similar redshifts in comparison to dye 1 in the UV–vis absorption spectra, there is a significant difference between JSC values of these dyes resulting in... 

Chemical vapour deposition (CVD) at atmospheric pressure, using TiCl 4 as a precursor, was used to grow nanostructured TiO2 films on glass substrates. At relatively low temperatures (∼245 °C) and using relatively high reactant concentrations, different nano-morphologies of TiO2 were formed simultaneously, such as spheres, nanowires and mesoporous structures. The TiO2 spheres were successfully applied as light-scattering particles in dye-sensitized solar cells, either by direct deposition onto electrodes in the reactor, or by preparation of a printing paste from the deposited particles. For dye-sensitized solar cells using the organic dye D35 as sensitizer and a cobalt-complex based redox... 

In this review, the importance of nanoparticles (NPs), with emphasis on their general and specific properties, especially the high surface-to-volume ratio (A/V), in many technological and industrial applications is studied. Some physical and chemical preparation methods for growing several metallic and binary alloy NP catalysts are reviewed. The growth and mechanism of catalytic reactions for synthesis of 1D nanostructures such as ZnO nanowires and multiwall carbon nanotubes (MWCNTs) are discussed. Gas-phase production with emphasis on dependence of catalytic activity and selectivity on size, shape and structure of NPs is also investigated. Application of NP catalysts in several... 

In the present work, the novel ternary Fe2O3/MoO3/AgBr photocatalyst with different dosages of AgBr was successfully synthesized via a facile method. The physicochemical properties of the resultant catalyst were characterized by using various techniques such as XRD, SEM, EDX, BET, XPS, DRS, and VSM. The photocatalytic performance of as-prepared samples was evaluated by degradation of organic dye acid blue 92 (AB92) under visible light irradiation, and in dark. The impact of different operating parameters namely calcination temperature, amount of photocatalyst, dye concentration, and pH of solution were investigated in degradation reaction. Ternary nanocomposite exhibited the best... 

Semiconductor-based photocatalysis is an efficient approach for degradation of organic pollutants. In this context, ZnO/g-C3N4 composite nanofibers containing carbonaceous species with different concentrations of g-C3N4 nanosheets (x = 0.25, 0.5, 1, 2, 10 wt%) noted as ZnO/carbon/(x wt%) g-C3N4 are prepared by electrospinning technique. For preparation of the composite nanofibers, bulk g-C3N4 is exfoliated to nanosheets, and then it is mixed with polyvinyl alcohol and appropriate zinc acetate content followed by electrospinning process. Thermal annealing of the as spun zinc acetate/poly(vinyl alcohol)/g-C3N4 nanosheets sample under N2 atmosphere leads to the formation of carbonaceous species...