CdS quantum dot-sensitized ZnO nanorod-based photoelectrochemical solar cells

ZnO nanorods have been grown using ZnO seed layer onto ITO-coated glass substrates. CdS quantum dots have been deposited onto ZnO nanorods using simple precursors by chemical method and the assembly of CdS quantum dots with ZnO nanorod has been used as photo-electrode in quantum dot-sensitized solar cells. X-ray diffraction results show that ZnO seed layer, ZnO nanorods, and CdS quantum dot-sensitized ZnO nanorods exhibit hexagonal structure. The particle size of CdS nanoparticle is 5 nm. The surface morphology studied using scanning electron microscope shows that the top surface of the vertically aligned ZnO nanorods is fully covered by CdS quantum dots. The ZnO nanorods have diameter ranging from 100 to 200 nm. The absorption spectra reveal that the absorption edge of CdS quantum dot-sensitized ZnO nanorods shift toward longer wavelength side when compared to the absorption edge of ZnO. The efficiency of the fabricated CdS quantum dot-sensitized ZnO nanorod-based solar cell is 0.69% and is the best efficiency reported so far for this type of solar cells.     

Interpenetrated molecules: crown-ether and linear organic molecule supramolecular architectures

In this review, pseudorotaxanes and rotaxanes structured out of simple crown ethers and linear organic molecules with positively charged nitrogen centres (i.e., quaternary pyridinium groups, viologens like paraquat and also extended viologens, imidazolium groups, benzimidazolium groups, bis-benzimidazolium groups and their derivatives) are described. Some selected examples of such systems are assembled here with respect to their properties and applications.     

Evaluation of splice loss in single-mode graded index fibres by a simple technique

We present simple and accurate analytical expressions for the evaluation of splice loss in single-mode graded index fibres. Our analysis is based on simple series expression for fundamental mode of such fibres which we have developed recently. Since splices are highly tolerant for longitudinal separation, we restrict our analysis to cases of transverse offset and angular tilt only. The concerned calculations require much less computations. With examples of step and parabolic index fibres, we show that our predictions agree excellently with the exact results. A useful collection of integration and differentiation formulae involving Bessel functions is presented in the appendix for ready reference to engineering problems of similar computational context.     

Optical limiting action of 2-amino 5-nitro pyridinium chloride crystal for laser safety devices

ABSTRACT

The liquid crystal (LC) displays with narrow bezel design require excellent physical properties such as high adhesion, low moisture permeability, and low LC contamination. Among the adhesive components, the heat curing agent is an important component in the adhesive and plays a key role in the adhesion between the epoxy resins. In this study, new UV/heat dual-curable adhesives involving a multi-functional heat-curing agent of branched polyethylenimine have been prepared and evaluated by adhesive strength, moisture permeability, and LC contamination measurements. It is shown that the proposed adhesives offer excellent adhesive properties for narrow-bezel applications.     

Solvothermal synthesis of hierarchically porous CeO2 nanopalm leaves and their photocatalytic properties

Hierarchically porous CeCO₃OH palm leaves were synthesized by using a facile solvothermal method at 180 °C utilizing cerium nitrate and ethylene glycol. Polycrystalline CeO₂ palm leaves were obtained from the thermal decomposition-oxidation process of the CeCO₃OH nanostructures. CeCO₃OH and CeO₂ palm leaves were characterized by X-ray diffraction pattern, scanning electron microscopy image, energy dispersive X-ray analyses, and ultraviolet (UV)–visible spectroscopy images. The CeO₂ palm leaves exhibited a significant photocatalytic performance in degrading azo dye acid orange II in an aqueous solution under an UV radiation. The formation mechanisms of the CeCO₃OH/CeO₂ nanostructures were described on the basis of the experimental results.     

Facile synthesis of ZnS/MnS nanocomposites for supercapacitor applications

Journal of Solid State Electrochemistry - In this study, we have reported a facile fabrication of pristine zinc sulfide (ZnS), manganese sulfide (MnS), and ZnS/MnS nanocomposites (NCs) via...     

Solvothermal synthesis of three‐dimensional CeO2 micropillows and their photocatalytic property

Three‐dimensional (3D) CeO₂ micropillows were synthesized by using solvothermal method. The pH of the precursor solution was adjusted to 10 by adding ammonium hydroxide. The structural, morphology and compositional characteristics of CeO₂ micropillows were investigated by XRD, SEM, TEM and EDAX. XRD analysis showed the formation of CeO₂ micropillows. BET analysis showed high specific surface area for the synthesized CeO₂ micropillows (191 m² g^–1). Optical absorption of CeO₂ micropillows showed enhanced photoabsorption ability with the estimated band gap energy of 2.8 eV. The photodegradation rate of the CeO₂micropillows was found to be 87% and obeys pseudo‐first‐order equation. The photocatalytic results indicated that the CeO₂ micropillows exhibit enhanced photocatalytic property towards azo dye acid orange 7 (AO7) under UV–Vis light illumination.

     

Unraveling the molecular recognition of "three methylene spacer" bis(benzimidazolium) moiety by dibenzo-24-crown-8: pseudorotaxanes under study

"Three methylene spacer" bis(benzimidazolium) derivatives act as a new template for threading dibenzo-24-crown-8 into [2]pseudorotaxanes. In this Article we sought to unveil the difference in the extent of threading of various "three methylene spacer" bis-benzimidazolium moieties based on differences in aromatic methyl substituent positions and anions through the macrocycle dibenzo-24-crown-8. The temperature of the systems were also varied (low temperatures of 240 K and 253 K), when such interwinding of the thread and crown were not detected at room temperature of 308 K. The presence of such threaded complexes was determined based on (1)H-NMR initially and finally corroborated by high resolution mass spectrometry and DFT calculations. 2D-NMR experiments ((1)H-(1)H-NOESY) proved to be a very important tool in elucidating the interaction present between the components of the pseudorotaxanes. The dethreading/rethreading process was studied. DFT optimized structures suggest lower energy H-bonding orientations and compare the effect of methyl substituents on the axle.     

Studies on optical absorption and structural properties of Fe doped CdS quantum dots

Fe doped CdS quantum dots have been prepared using simple precursors by chemical precipitation technique. Fe doped CdS quantum dots have been synthesized by mixing cadmium nitrate, sodium sulfide and adding Fe under suitable conditions. X-ray diffraction analysis reveals that undoped and Fe doped CdS crystallizes in hexagonal structure. The lattice constants of Fe doped CdS nanoparticles decreased slightly with incorporation of Fe and no secondary phase was observed. The average grain size of the nanoparticles is found to lie in the range of 2.8–4.2 nm. HRTEM results show that undoped and 3.75% Fe doped CdS nanoparticles exhibit a uniform size distribution and average size of the nanoparticles is about 2–3 nm. Raman spectra show that 1LO and 2LO peaks of the Fe doped CdS samples are slightly red shifted compared with those of undoped CdS. Optical absorption spectra of Fe doped CdS nanoparticles exhibited red shift.