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The rapid increase in energy consumption has severely rehabilitated human life urging to develop reliable and environmental friendly energy storage devices. Target oriented, systematic approach has been adopted to synthesis La doped CeO 2 nanostructures with percentage as La x Ce 1-x O 2 (X = 0,1,3,5,7) for potential super capacitors applications. Morphological doping impact on H 2 production, electrochemical and optical properties are thoroughly investigated. XRD studies revealed the crystalline phase purity and attained approximately 35 nm average crystallite size. The SEM images exposed that primary morphology nano-particles has been tuned into nanorods by increasing the La concentration in CeO 2 with size range 40∼60 nm. CV graphs depicted that the prepared electrodes obey the pseudo capacitive faradaic reactions behavior in nature. Maximum capacitance (925 F g-1) has been achieved by La 0·05 Ce 0·95 O 2 which is better than numerous reported materials. The La 0·05 Ce 0·95 O 2 also exhibited excellent GCD stability with 87.8% retention exhibiting it suitability for supercapacitor applications. Furthermore, the La 0·05 Ce 0·95 O 2 showed the significantly higher H 2 (9 μmol h−1g−1) production rate as compared to undoped CeO 2 and La 0·01 Ce 0·99 O 2, La 0·03 Ce 0·97 O 2 samples. This higher production is attributed to the recombination rate and have strong substantial correlation with optical characteristics. [Display omitted] • La doped CeO 2 nanorods successfully synthesized by hydrothermal method. • Specific capacitance 925 F g-1 has been achieved for La 0·05 Ce 0·95 O 2 nanorods. • More than 87% cyclic stability was achieved for La 0·05 Ce 0·95 O 2 nanorods. • The La 0·05 Ce 0·95 O 2 showed the significantly H 2 production rate (9 μmol h−1 g−1). [ABSTRACT FROM AUTHOR]

Lemon is an essential therapeutic plant of the Rutaceae family having a variety of vital phytochemicals. The TiO2 nanoparticles (NPs) have been synthesised by the green synthesis method from lemon peel extract for the first time. Hydrolysed extract of lemon peel contains hesperidin flavanol that releases aglycone to act as a capping and reducing agent. The Synthesised samples are characterised through X-rays diffraction spectroscopy (XRD), energy dispersive X-rays spectroscopy (EDX), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and ultraviolet and visible (UV–Vis) spectroscopy techniques. The SEM results depict that the prepared specimen is purely comprised of the agglomerated structures. A close study from TEM exhibits the spherical shape of the particles with the particle size ranges from 80 to 140 nm and anatase form according to the XRD. The Tauc plot prepared from the UV–Vis spectrum shows a bandgap of 3.08 eV. Photocatalytic response of the prepared TiO2 for the degradation of rhodamine B (RhB) is also studied. The results showed that synthesised particles possess more than 70% photocatalytic activity which is more efficient as compared to commercial TiO2 particles. [ABSTRACT FROM AUTHOR]

[Display omitted] • Pristine and Mo-doped (0, 1, 2, 3, 4 and 6 %) NiO regular nanoparticles have been synthesized successfully. • Drastic reduction in band gap occurs from 3.5 eV to 2.9 eV at 3 wt% Mo occurs owing to average crystallite size decrease from 67 nm to 44 nm. • The sample containing 3 wt% Mo doped NiO showed highest efficiency (90% degradation) for MB dye, whereas with RhB dye it shows 98% degradation. • The PL analysis revealed that the Molybdenum substitution in NiO host lattice specifically reduces the recombination rate with an improved photo-efficiency. • The reaction kinetics examination showed pseudo-first-order kinetics with an improved rate constant. Semiconductor materials are in leading role for elimination of organic pollutants in water with an effective tuning of bandgap and improving their photocatalytic activity. Pristine and Mo-doped (0, 1, 2, 3, 4 and 6 %) NiO nanoparticles have been synthesized by sol–gel method. The synthesized nanoparticles were examined by XRD, SEM, EDS, UV–visible spectroscopy and photoluminescence (PL) analysis. The synthesized nanoparticles exhibit spherical morphology and their crystallite size decreases with an increase in Mo concentration. The average crystallite size decreases from 67 nm to 44 nm and the drastic reduction in band gap occurs from 3.5 eV to 2.9 eV at 3 wt% Mo doping. The photocatalytic activity against Rhodamine-B (RhB) and methylene blue (MB) showed that the Molybdenum doping improves the performance of NiO photocatalyst. The PL analysis revealed that the Molybdenum substitution in NiO host lattice specifically reduces the recombination rate with an improved photo-efficiency. The reaction kinetics examination showed pseudo-first-order kinetics with an improved rate constant. The sample containing 3 wt% Mo doped NiO showed highest efficiency among all the prepared samples. The sample with 3 wt% doping shows 90% degradation after 90 min when using against MB dye, whereas with RhB dye it shows 98% degradation in 120 min. The retention of high performance after five consecutive cycles confirms the reusability of synthesized nanoparticles. [ABSTRACT FROM AUTHOR]

The pure TiO2 nanoparticles have been synthesized by a simplistic eco-friendly green method using extract of cinnamon powder for the first time. The cinnamic acid present in the cinnamon works as the capping agent during the reaction. TiO2 nanoparticles were characterized by using X-ray diffraction (XRD) which conformed the anatase phase TiO2 with average crystallite size 70.1 nm. Scanning electron microscopy (SEM) micrographs suggests that the particles exhibit spherical shapes and uniformly distributed over the surface with size range 70–150 nm. The energy dispersive X-ray spectroscopy (EDX) shows the presence of oxygen and titanium peaks which confirmed the formation of TiO2 pure nanoparticles. From the UV–Vis spectroscopic studies the band gap comes out to be 3.2 eV which confirmed the formation of TiO2 nanoparticles. The optical properties have also been studied by PL that indicates the formation of oxygen vacancies and self-trapped excitons in the material. The samples showed the enhanced photocatalytic property. [ABSTRACT FROM AUTHOR]

High quality square shaped GaN nano-rods are successfully synthesized by a novel method of precursors pretreatment with aqueous NH 3 via CVD method at 1300 °C. The pre-treatment effect significantly enhanced the conductivities, carrier concentrations and mobilities in GaN nanorods. GaN nanowires have also been synthesized at 1300 °C without treating precursors with aqueous NH 3. Diameter of the nanorods and nanowires are measured in the range of 100-200 nm whereas length is in tenth of microns. Room temperature PL analysis of GaN nanowires displayed a high intensity near-band-edge emission at 370 nm with week blue emission. The GaN square nanorods exhibited the yellow band emission at 565 nm vanishing the weak blue emission along with the near-band-edge emission at 369 nm indicating their potential applications in optoelectronics. The carrier concentrations (N d) are calculated to be 3.65–5.25 × 1016 cm−3 and 2.25∼5.88 × 1018 cm−3 for nanowires and nanorods respectively. The electron mobilities (μ) calculated for the GaN nanowires were in the range of 200∼300 cm2/Vs where as for the nanorods were 154∼625 cm2/Vs. The high quality GaN nanorods building blocks with high conductivities, career densities and mobilities will be a tremendous breakthrough in low voltage operating nano-devices. • Square shaped GaN NRs pre-treated with aqueous NH 3 have been synthesized. • N d for pre-treated square shape GaN NRs was 2.25∼5.88 × 1018cm−3. • Strong PL emission peak at 369 nm was measured for pre-treated NRs. • Yellow peak at 565 nm was observed attributed to Ga vacancies in NRs. [ABSTRACT FROM AUTHOR]

Abstract: Durian-like gallium nitride (GaN) microstructures were successfully synthesized on Si substrate by pre-treating Ga metal with aqueous NH3 via catalyst assisted chemical vapor deposition (CVD) method at 1200°C. The as-synthesized product was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). XRD and EDX analysis revealed that durian-like GaN is pure and single phase. SEM results showed that the size of the durian-like GaN structures was 20–25μm. GaN microstructures exhibited reasonable field emission properties with the turn-on field of 8.24Vμm−1 (0.01mAcm−2) and threshold field of 10.18Vμm−1 (1mAcm−2) which is sufficient for applications of electron emission devices, field emission displays and vacuum micro-electronic devices. Photoluminescence (PL) properties of durian-like GaN studied at room temperature showed a strong near-band-edge emission at 369.4nm (3.36eV) whereas at low temperature it showed near-band-edge emission at 364.2nm (3.4eV) without yellow band emissions. The photoluminescence properties showed that it has also potential application in light-emitting devices. [Copyright &y& Elsevier]

[Display omitted] • TiO 2 nanoparticles have been synthesized by green synthesis technique using Citrus Limetta extract. • The citric acid present within the extract acted as reducing and capping agent for nanoparticles synthesis. • TiO nanoparticles are of spherical shape with size ranging from 80 to 100 nm confirmed by SEM and TEM. • Photocatalytic performance of the TiO 2 nanoparticles was studied w.r.t time and catalyst concentration. • Excellent performance for RhB dye degradation showed that it can be potential candidate for water purification. In this research work, TiO 2 nanoparticles has been prepared by eco-friendly green synthesis technique using Citrus Limetta extract which is rarely used. The citric acid present within the extract acted as reducing and capping agent for nanoparticles resulting pure TiO 2 nanoparticles. The synthesized nanoparticles are characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), UV–vis spectroscopy and photoluminescence (PL) analysis. The synthesized nanoparticles are approximately 80–100 nm in size, spherical in shape and distribution of the nanoparticles was almost uniform all over the sample. The calculated band gap of nanoparticles was 3.22 eV which confirmed the formation of anatase phase TiO 2 nanoparticles. The enhanced photocatalytic activity with respect to time and catalyst concentration was examined for RhB acting as a model dye which is better than many reported results. Almost 90% dye was degraded within 80 min which shows its excellent photocatalytic efficiency. [ABSTRACT FROM AUTHOR]

Simple, low cost spray pyrolysis technique is implemented herein to deposit thin film of Cu 2 SnS 3 on a glass substrate for photovoltaic applications. Structural, physical, chemical and optical properties of the thin film were analyzed by XRD, SEM, AFM and UV-VIS spectroscopy. The XRD pattern indicated tetragonal phase of the deposited Cu 2 SnS 3 thin film having major XRD peaks at 2θ of 28.54°, 33.07° and 47.47° corresponding to the (112), (200), and (220) planes. It was inferred from SEM and AFM micrographs that the surface was smooth without any pinholes or cracks. The root mean square value of film surface roughness was found to be 11.74 nm and film thickness was measured 200 nm. The AFM and SEM results indicated that the deposited thin film was densely packed and strongly adhered to the substrate. The energy band gap of the deposited Cu 2 SnS 3 thin film was found to be 1.6eV via UV–Vis spectroscopy. [ABSTRACT FROM AUTHOR]

• Doping of transition-metals i.e. chromium in CdS 1D nanoneedles. • First study about the Cr-effect on optical and magnetic properties of 1D Cr-doped CdS nanoneedles. • Role of Cr in CdS nanoneedles for tunable emission. • Detection of luminescence related to chromium for the first time. • Chromium incorporated into CdS nanoneedles produced emission in the infrared region. • Cr-doped CdS nanoneedles showed ferromagnetism. Spin controlled diluted magnetic semiconductors (DMSs) could bring revolution in the processing speed as well as in enhancing the storage capacity. To achieve its industrial application, several impurities have been doped from the 3d/4f into semiconductors, however, Cr has not yet been doped into CdS 1D nanostructures. Here, in the present study, we report on the Cr-doped CdS 1D nanoneedles synthesized by CVD and studied its optical and magnetic properties. The successful incorporation of Cr-ions into CdS confirmed by EDX and XRD. Along with the increase in Cr-ions concentration, first PL-peak shifted from 514.1 to 558.3 nm associated with the formation of excitonic magnetic polarons (EMPs) and the second peak centered at 993.8 nm may correspond to the aggregation of Cr-ions. For the first time, we tuned CdS emission up to ~ 482 nm covering visible spectral region up to near-infrared (NIR) region. With increasing the Cr-ions concentration up to 6.2%, saturation magnetization (Ms) was significantly enhanced from 0.614 × 10−3 Am2/kg to 0.987 × 10−3 Am2/kg. These findings will promote their future applications in the optoelectronic and spintronic devices. [ABSTRACT FROM AUTHOR]

This paper reports the fabrication and characterization of nontoxic heterojunction of ZnO/CuO. The films were characterized through X-ray diffraction, UV spectroscopy and field emission scanning electron microscope (FESEM). The valence and conduction band edges were measured through Photo-Electron spectroscopy in air. The electrical parameter for FTO/ZnO/CuO/In heterojunction diode such as ideality factor, barrier height, and series resistance were calculated by using conventional forward bias I–V characteristics and also verified with the help of Cheung method. The high value of ideality factor was attributed to high series resistance, defects, other phases of CuO and recombination at interface and within bulk. The double logarithmic graph of current and voltage showed that the transport mechanism is due to the space charge limited current and trapped charge limited current. Photovoltaic parameters Voc of ∼190 mV and Jsc of ∼0.40 mA/cm 2 of FTO/ZnO/CuO/In heterojunction were recorded. [ABSTRACT FROM AUTHOR]

[Display omitted] The novel study of Cd-Zn co-doped Magnesium ferrites Cd x Zn 1-x Mg 0.25 Fe 1.75 O 4 (where x = 0, 0.25, 0.75, 0.50, and 1.00) has been made successfully by adopting a facile sol-gel extended hydrothermal pathway. Structural, optical, and magnetic behavior of the Cd-Zn co-doped Magnesium ferrites were systematically analyzed. From the X-ray Diffraction (XRD) patterns it was confirmed that the prepared samples have a cubic spinel structure. Scanning electron microscopic (SEM) study revealed the agglomerated and irregular shape of Cd-Zn co-doped Magnesium ferrites nanoparticles. Fourier transforms infrared (FTIR) spectroscopy has been studied for the confirmation of the presence of (M-O) bonding in the synthesized samples. Furthermore, the synthesized samples showed two frequency bands related to phonon vibrational stretching in both octahedral and tetrahedral lattice positions. The PL spectrum revealed the strong emission peaks in the ultraviolet to the visible region of all the synthesized samples. Raman spectroscopy showed the formation of four active modes due to the cubic spinel structure of all samples. Finally, the magnetic characteristics are calculated by using a vibrating sample magnetometer (VSM) showing ferrimagnetic and soft magnetic behavior of all the Magnesium ferrite samples. As the Cd and Zn co-doping in Mg ferrites was increased, the H c was decreased. The magnetic studies revealed that the maximum H c of 576 Oe and maximum saturation magnetization (M s) appeared for the sample Cd 0.50 Zn 0.50 Mg 0.25 Fe 1.75 O 4 , carrying Cd/Zn in 50/50 ratio. It is envisaged that the novel preparation of Cd-Zn co-doped Magnesium ferrite would be suitable for several applications, for example, magnetic recording devices, actuators, high-density data storage devices sensors, and biomedical equipments. [ABSTRACT FROM AUTHOR]

Abstract: Here we report catalyst-free combined synthesis of metal/semiconductor Zn/ZnO core/shell microspheres with hollow interiors on Si substrate and metallic Zn polygonal microparticles on glass substrate in a single experiment via thermal evaporation and condensation technique using nitrogen (N2) as carrier agent at 800°C for 120min. The Zn/ZnO hollow microspheres were observed to have dimensions in the range of 70–80μm whereas metallic Zn microparticles with polygonal cross section and oblate spherical shape were found to be of 8–10μm. Some of the Zn/ZnO core/shell hollow spheres were also observed to have single crystalline ZnO pointed rods in extremely low density grown on the outer shell. The structural, compositional and morphological characterization of the products obtained on the substrates were performed by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and selected area electron diffraction (SAED). A vapor–liquid–solid (VLS) process based growth mechanism was proposed for the formation of Zn/ZnO core/shell microspheres with hollow interior. The optical properties of Zn/ZnO core/shell microspheres were investigated by measuring the photoluminescence (PL) spectra at room temperature (RT). Two very strong emission bands were observed at 373 and 469nm in the ultraviolet and visible regions respectively under excitation wavelength of 325nm. Also the effect of the various excitation wavelengths on the PL behaviour was studied at room temperature. PL studies of Zn/ZnO core/shell microspheres show the promise of the material for applications in UV and blue light optical devices. [Copyright &y& Elsevier]

Zinc and cadmium based cobalt ferrites Zn x Cd 0.375-x Co 0.625 Fe 2 O 4 (where x = 0, 0.075, 0.125, 0.25) were successfully synthesized by a facile co-precipitation technique. Structural, optical and magnetic characteristics of the doped ferrites were systematically analyzed. X-ray Diffraction (XRD) pattern confirmed the formation of cubic spinel structure in all samples. Scanning electron microscopic analysis of surface morphology revealed cubic and spherical shaped ferrite particles. Fourier transform infrared (FTIR) spectroscopy confirmed the existence of metal oxygen (M − O) bonding in the prepared samples. Moreover, the prepared samples exhibited two frequency bands corresponding to phonon vibrational stretching in both octahedral and tetrahedral lattice positions. The optical properties were investigated in detail through photoluminescence (PL) spectroscopy and Raman spectroscopy. The PL spectrum confirmed the strong emission peaks in the ultraviolet to visible region of all the samples. Further, four active Raman modes, associated with cubic spinel structure are identified in all prepared samples. Finally, the magnetic characteristics are evaluated by using vibrating sample magnetometer (VSM) revealing ferrimagnetic and soft magnetic behavior of the samples. As the Zn and Cd co-doping in Co was increased, the H c was decreased. The magnetic studies show the maximum H c of 576 Oe for Cd doped cobalt ferrite, and maximum saturation magnetization (M s) for Zn–Cd doped cobalt ferrite. It is envisaged that the newly prepared Zn–Cd co-doped cobalt ferrite would be appropriate for a number of important applications, for example, magnetic recording devices, sensors, actuators, high-density data storage devices, and biomedical equipments. [ABSTRACT FROM AUTHOR]

Abstract: Here we report on the synthesis of novel SnO2 nanofibers bundle (NFB) by using ball milled Fe powders via chemical vapor deposition (CVD). The reaction was carried out in a horizontal tube furnace (HTF) at 1100°C under Ar flow. The as prepared product was characterized by X-ray diffraction (XRD), scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, high resolution transmission electron microscopy and selected area electron diffraction (SAED). The microscopy analysis reveals the existence of tubular structure that might be formed by the accumulation of nanofibers. The Raman spectrum reveals that the product is rutile SnO2 with additional peaks ascribed to defects or oxygen vacancies. Room temperature Photoluminescence (PL) spectrum exhibits three emission bands at 369, 450 and 466.6nm. Using optical absorbance data, a direct optical bandgap of 3.68eV was calculated. [Copyright &y& Elsevier]

Abstract: Large scale metallic cadmium (Cd) nanotubes with high purity have been obtained on glass substrate by catalyst-free thermal decomposition of cadmium oxide (CdO) powder at 1200 °C for 120 min using argon (Ar) gas as carrier agent inside an alumina tube mounted in horizontal tube furnace. The structural, compositional and morphological characterizations of cadmium nanotubes (CdNTs) were performed by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED). The CdNTs were observed to be single crystalline with 60–70 nm diameter and tens of micrometre length. Based on vapour–solid (VS) and rolling layer mechanisms, growth process has been proposed for the formation of CdNTs. Room temperature photoluminescence (PL) spectrum for CdNTs recorded under xenon light wavelength of 325 nm exhibited a very prominent emission band at 383 nm which may be ascribed to either surface oxidation effects or radiative recombination of electrons in the s, p conduction band near the Fermi surface and the holes in the d bands generated by xenon light excitation. This shows the promise of CdNTs for applications in UV-light emitting devices. [Copyright &y& Elsevier]

Abstract: In this paper, stannous oxide (SnO) nano flowers self-assembled with nano petals have been successfully synthesized with template-free hydrothermal growth method by using SnCl2.2H2O and KOH as raw materials. The crystalline phase, morphology, particle sizes and component of the as-prepared materials were characterized by using X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) and energy-dispersive X-ray spectroscopy (EDS). FESEM results had showed that the flower like SnO structure was in the range of 4–7μm. The average crystalline size of the tetragonal phase SnO nano-particles was calculated about 22nm from the full-width at half-maximum of XRD. Furthermore, Ultraviolet–visible–near infrared (UV–vis–NIR) spectrophotometry was used to determine the transmittance behavior of SnO nano structures. Direct optical band gap of 3.13eV was acquired by Davis–Mott model. Moreover, photoluminescence (PL) emission spectrum of SnO nano-petals at room temperature exhibited a very prominent violet emission at 398nm that corresponds to direct band emission. [Copyright &y& Elsevier]

Abstract: We report here the simultaneous growth of ZnSe cactus-like structures with nanorods emerging from their surface and selenium microflowers using Zn and Se powders as precursors. ZnSe cactuses were obtained by solid state chemical reaction whereas selenium microflowers were obtained by thermal evaporation and condensation process. ZnSe cactuses consist of spheres with diameter range 2–3μm having nanorods with diameter in the range 60–90nm on the exterior surface. The mixture of zinc and selenium powders with few drops of aqueous ammonia loaded in semicircular long alumina boat was heated inside horizontal tube furnace at 500°C for 180min under ammonia atmosphere. The structural, compositional and morphological characterizations have been performed by means of Scanning Electron Microscope (SEM), the Energy Dispersive Spectroscopy (EDS) and X-ray diffraction (XRD). Room temperature photoluminescence (PL) measurement of as-synthesized products show two intensive peaks centered at 404nm and 427nm (2.85eV), which are attributed to the band edge emission of ZnSe. These two strong emission bands are blue shifted; this blue shift is because of quantum size confinement effect of nanostructures. A very weak peak centered at 464nm (2.67eV) is also observed in our sample which is exactly equivalent to the peak associated with the bulk ZnSe, and is attributed to near band edge emission (NBE) for the ZnSe nanostructures. [Copyright &y& Elsevier]

Abstract: Zinc nitride nanoneedles (ZNNs) with diameters at stem and tip parts as 200–300nm and 30–70nm respectively have been prepared by the nitridation of ball-milled zinc powders at 600°C for 120min under NH3 gas environment. The structural, compositional and morphological characterizations of the product were conducted by X-ray diffraction, energy dispersive X-ray spectroscopy, scanning electron microscopy and transmission electron microscopy. From transmission spectrum data, an indirect band gap of 2.72eV has been calculated for ZNNs whereas photoluminescence studies exhibited a strong UV excitonic mission band at 395nm as well as two weak defect related blue emissions at 453 and 465nm. A vapor–solid (VS) process based growth mechanism for the formation of ZNNs has also been discussed briefly. [Copyright &y& Elsevier]

Abstract: Metal–semiconductor Zn–ZnO core–shell microcactuses have been synthesized on Si substrate by simple thermal evaporation and condensation route using NH3 as carrier gas at 600°C under ambient pressure. Microcactuses with average size of 65–75μm are composed of hollow microspheres with high density single crystalline ZnO rods. The structure, composition and morphology of the product were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), scanning electron microscope (SEM), transmission electron microscopy (TEM) and selected area electron diffraction (SAED). A vapor–liquid–solid (VLS) based growth mechanism was proposed for the formation of Zn–ZnO core–shell microcactuses. Room temperature photoluminescence (PL) investigations revealed a strong and broad blue emission band at 441nm associated with a weak ultraviolet (UV) peak at 374nm. This blue emission (BE) is different from usually reported green/yellow-green emission from Zn–ZnO or ZnO structures. The field emission (FE) measurements exhibited moderate values of turn-on and threshold fields compared with reported large field emissions for other materials. These studies indicate the promise of Zn–ZnO core–shell microcactuses for the applications in UV-blue light display and field emission microelectronic devices. [Copyright &y& Elsevier]