ZnSe Nanorods Research Articles

Temperature dependent photoluminescence of surfactant assisted electrochemically synthesized ZnSe nanostructures

In the present study, the zinc selenide (ZnSe) nanostructures developed by a cost-effective and straightforward electrodeposition method on tin-doped indium oxide (ITO). To examine the effect of surfactant on ZnSe nanostructure, Triethanolamine, Triton X-100, Hydrazine hydrate, and Ethylene diamine tetraacetic acid were the surfactants. The ZnSe nanostructures synthesized at 338 K by applying constant current density. The ZnSe nanorods, nanospheres, and nano-syringes developed using the galvanostatic mode of electrodeposition with the addition of different surfactant. The ZnSe nanostructures are characterized using various analytical tools. The X-ray diffraction spectroscopy (XRD), FT-Raman spectroscopy (FR-Raman), FTIR spectrum and X-ray photoelectron spectroscopy (XPS) are used to study structural properties. The UV–Vis spectroscopy is used to examine optical behavior. The field emission scanning electron microscopy (FESEM) engaged to study morphological features and the role of surfactant in the formation of ZnSe nanostructures. The spectrofluorometer is used to study the photoluminescence properties of ZnSe nanostructures. The present study focuses on the study of the role of surfactant in the development of ZnSe nanostructures and consequent temperature dependent photoluminescence properties. In the temperature dependent photoluminescence, the emission intensity is observed to vary with changing temperature.

Controlling Anisotropic Growth of Colloidal ZnSe Nanostructures.

Semiconductor nanocrystals serve as outstanding model systems for studying quantum confined size and shape effects. Shape control is an important knob for controlling their properties but so far it has been well developed mainly for heavy-metal containing semiconductor nanocrystals, limiting their further widespread utilization. Herein, we report a synthesis of heavy-metal free ZnSe nanocrystals with shape and size control through utilization of well-defined molecular clusters. In this approach, ZnSe nanowires are synthesized and their length and shape control is achieved by introduction of controlled amounts of molecular clusters. As a result of [Zn4(SPh)10](Me4N)2 clusters (Zn4 clusters) addition, short ZnSe nanorods or ZnSe nanodots can be obtained through tuning the ratio of Zn4 clusters to ZnSe. A study using transmission electron microscopy revealed the formation of a hybrid inorganic-organic nanowire, whereby the ligands form a template for self-assembly of ZnSe magic size clusters. The hybrid nanowire template becomes shorter and eventually disappears upon increasing amount of Zn4 clusters in the reaction. The generality of the method is demonstrated by using isostructural [Cu4(SPh)6](Me4N)2 clusters, which presented a new approach to Cu doped ZnSe nanocrystals and provided also a unique opportunity to employ X-ray absorption fine structure spectroscopy for deciphering the changes in the local atomic-scale environment of the clusters and explaining their role in the process of the nanorods formation. Overall, the introduction of molecular clusters presented here opens a path for growth of colloidal semiconductor nanorods, expanding the palette of materials selection with obvious implications for optoelectronic and biomedical applications.

Continuous Flow Synthesis of Anisotropic Cadmium Selenide and Zinc Selenide Nanoparticles

AbstractAnisotropic semiconductor nanoparticles find use in various applications ranging from electronics to photocatalysis and biolabeling. Batch synthesis methods typically used for their synthesis are often hampered by slow mixing, slow heating/cooling, and lack of batch‐to‐batch reproducibility, especially when scaling up. The modular continuous flow reactor reported here overcomes some of these challenges. It enables air‐sensitive syntheses at temperatures as high as 750 °C, supports rapid heating and cooling times (≈1 s or less), and enables syntheses that involve reagents that are viscous or even solid at room temperature. For validation we pursued two systems: the synthesis of (i) CdSe nanorods and bipods, and of (ii) ZnSe nanorods. Nanoparticles with low variance in quantum confined dimension (width) −16 % for CdSe and 11 % for ZnSe were obtained. For comparison, the same products were also synthesized using two batch approaches, hot‐injection and heat‐up, under similar conditions. The batch products were less uniform: 30 % variance in quantum confined dimension. Furthermore, the lack of precise temperature control in the batch processes resulted in CdSe nanorods with irregular‐shaped, jagged branches whereas the continuous process produced CdSe nanorods with uniform, straight branches. The modular continuous flow reactor design is suited for scale up, allowing working flow rates as high as ≈10 mL min−1, which translates into a production rate of ≈158 g day−1 for CdSe.

Effect of 10 MeV energy of electron irradiation on Fe2+ doped ZnSe nanorods and their modified properties

The Fe2+-doped ZnSe nanorods are synthesized using simple potentiostatic mode of electrodeposition on the tin-doped indium oxide (ITO) substrate. To study the effect of electron irradiation, the 10-MeV energy has been applied on 1 % Fe2+-doped ZnSe nanorods with different doses such as 10, 20 and 30 kGy. After electron irradiation, structural, morphological, optical, electrochemical and photoelectrochemical properties have been investigated. Due to high energy electron irradiation dose, drastic changes have been observed in the morphological properties; hence, changes have been observed in photoelectrochemical properties also. Due to high-energy, nanorods are destroyed and the photoelectrochemical cell performance (PEC) has been decreased.

Synthesis, field emission properties and optical properties of ZnSe nanoflowers

ZnSe nanoflowers have been synthesized by reaction of Se powder with Zn substrates at low temperature. The as-prepared ZnSe nanoflowers were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), X-ray energy dispersive spectroscope (EDS) and Raman spectroscopy measurements. It was found that the morphologies of the as-prepared samples highly depended on reaction time. ZnSe nanoclusters and nanoflowers formed at 573K when the reaction time was 20 and 60min, respectively. The as-prepared ZnSe nanoflowers were composed of radically aligned ZnSe nanorods with smooth surfaces. The results of XRD, XPS, EDS, TEM and Raman showed that the as-prepared ZnSe nanocrystals were single crystals with cubic zinc blende (ZB) structure. The formation mechanism of the as-prepared ZnSe nanoflowers was also discussed. In addition, the as-prepared ZnSe nanoflowers had excellent electron emission properties. The turn-on field of the as-prepared ZnSe nanoflowers was 3.5V/μm and the enhancement factor was 3499. The optical properties of the as-prepared ZnSe nanoflowers were also investigated. The results demonstrated that the as-prepared ZnSe nanoflowers were potential candidates for optoelectronic devices.

Fabrication and Photocatalytic Properties of ZnSe Nanorod Films

ZnSe nanorod films grown on fused quartz glass substrates via a simple two-step synthesis protocol were demonstrated to be environmentally safe and effective recyclable photocatalysts. These films showed greatly enhanced photocatalytic activity compared to pulsed laser deposition ZnSe films in the degradation of methyl orange dye solutions. The well-crystalized ZnSe nanorods had a length of 15 µm and a diameter of 200 nm and were densely grown on the substrate. The morphology, crystal structure, crystal phase, and photophysical properties of the ZnSe nanorod films were investigated using field-emission scanning electron microscopy (FE-SEM), UV-Vis spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), and high resolution transmission electron microscopy (HRTEM).

Photoelectrochemical cell studies of Fe2+ doped ZnSe nanorods using the potentiostatic mode of electrodeposition

The Fe2+ doped ZnSe nanorods are synthesized using simple potentiostatic mode of electrodeposition on the ITO substrate. In order to study the doping effect of Fe2+ in ZnSe, varied the doing percent such as 0.5%, 1%, 1.5%. These films are characterized for structural, compositional, morphological, optical and electrochemical properties using the X-ray diffraction study (XRD), X-ray photoelectron spectroscopy, field emission scanning electron microscopy, UV–vis spectroscopy and electrochemical spectroscopy. Along with these Raman spectroscopy and photoluminescence spectroscopy have been studied for understanding the characteristics vibrations of ZnSe and luminescence of ZnSe nanorods. FE-SEM shows the nanorods like morphology. Photoelectrochemical cell performance studied using the J–V measurement and it shows the maximum efficiency at 1% Fe2+ doped ZnSe nanorods. The observed maximum efficiency of Fe2+ doped ZnSe nanorods is 0.32%.

Tailoring of Morphology and Optical Properties of Bishydrazone-Capped ZnSe Nanorods

Hydrazone derivatives containing heterocyclic moieties have interesting ligational features. Various heterocyclic base ligands have been gradually used to synthesize nanomaterials; however, adapting task-specific ligand systems to guide the synthesis path towards desirable nanostructures and morphologies is rare. In this article, bishydrazone was used as a ligand to purposely modify the morphological structure of the zinc selenide nanostructures via wet chemical reaction method at room temperature. The as-prepared ZnSe nanorods are relatively uniform with an average diameter of ~100 nm at the core and top diameter of 8–10 nm. UV-Vis spectrum of the products displayed absorption maxima at 390 nm. Therefore, the obtained ZnSe nanorods may have promising applications in blue emitters, catalysts, and gas sensors. The presence of bishydrazone in the ZnSe nanorods is confirmed by the Fourier transform infrared spectrum. It would be expected that bishydrazone could be used to prepare other nanoscale metal selenides with special morphologies and improved properties on a large scale.

Chemical synthesis and functional properties of hexamethylenetetramine capped ZnSe nanorods

One-dimensional ZnSe nanorods were synthesized by a wet chemical method. Hexamethylenetetramine (HMTA) was used as a capping agent to prevent agglomeration. X-ray diffraction (XRD) pattern revealed the formation of the cubic crystal structure of ZnSe. Band gap was found to be 3.05eV from the optical absorption analysis. The surface passivation of HMTA on the ZnSe nanorods was confirmed by the Fourier transform infrared spectroscopy (FTIR) analysis. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) images revealed the formation of nanorods. The nanorods were 1–3µm long and 100nm in average diameter. A possible growth mechanism for their formation is proposed.

Vortex-Pattern Self-Assembly in Mn-Doped ZnSe Nanorods

Spontaneous patterning of anisotropic nanostructures into ordered assemblies remains a challenging quest, which requires controlled innovative approaches. One way to achieve such ordering of 1D nanorods is by manipulating the varieties of interactions (attractive and repulsive forces) present in colloidal solutions of anisotropic nanocrystals. The other ingenuous pathway is solvent-evaporation-mediated self-organization of the 1D nanorods. By following the second protocol, we have achieved exclusive pillar self-assembled patterns of visible-light-emitting Mn-doped ZnSe nanorods. The nanorods also exhibit intriguing vortex patterning observed by directional solvent evaporation from the nanorod solution. The effect of solvent evaporation to generate such unique morphologies on the TEM grid is discussed and the reported procedure to obtain the assembled patterns of visible-light-emitting, doped nanorods might be useful for future technological applications.

Gas-phase anion exchange towards ZnO/ZnSe heterostructures with intensive visible light emission

Gas-phase anion exchange was employed to convert ZnO nanorods into a ZnO/ZnSe heterostructure or pure ZnSe nanorods. The product showed intensive visible light emission, which was attributed to the VZn-related defect complexes in the ZnO core.

Effects of annealing on the photoluminescence of ZnSe nanorods coated with Au

Au-functionalized ZnSe nanorods were synthesized by the thermal evaporation of ZnSe powder followed by Au sputter-deposition and thermal annealing. Photoluminescence (PL) showed that the intensity of near-band edge (NBE) emission of ZnSe nanorods was enhanced remarkably by Au-coating and annealing in a H2 atmosphere. The intensity ratio of NBE emission to the deep level emission, INBE/IDL of Au-coated ZnSe nanorods after annealing in a H2 atmosphere was ∼68 times higher than that of the pristine (unannealed, uncoated) ZnSe nanorods. The increase in INBE/IDL might be due to a combination of carrier transfer from the defect level to the Fermi level of Au nanoparticles, surface plasmon resonance in Au nanoparticles and hydrogen passivated deep level defects.

Structural, morphological and optical properties of chelating ligand passivated ZnSe nanorods

Zinc selenide (ZnSe) nanorods have been synthesized using a shiff base ligand as a passivating agent at room temperature. The structure and morphology of ZnSe nanorods have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The SEM and TEM images reveal the formation of rod like nanostructures. The hexagonal wurtzite structure with the lattice constant of 5.63Å has been predicted from XRD results. LO and TO phonon frequencies of ZnSe nanorods have been observed at 206cm−1 and 247cm−1 respectively. Strong “blue shift” absorption and the enhanced luminescence property with respect to bulk have been observed from UV–vis spectrophotometry and photoluminescence spectrophotometry (PL).

Material Diffusion and Doping of Mn in Wurtzite ZnSe Nanorods

Light-emitting transition metal ion doped 1D nanorods can be a suitable candidate for fabrication of the advanced opto-electronic-based nanodevices. Among various doped nanocrystals, Mn doped ZnSe nanocrystals are widely studied for their intense Mn d–d emission. However, this is mostly performed in the zinc blende phase of spherical ZnSe quantum dots. But, herein we study the strategy to dope Mn ions in wurtzite phase of 1D ZnSe nanorods. To achieve this, it is essential to control the 1D crystal growth of ZnSe to facilitate the adsorption of dopants. The anisotropic 1D nanostructures are designed following thermally controlled material diffusion process rather than the most widely expected kinetically driven crystal growth protocol, and the dopants are introduced at the appropriate stage of the growth for their adsorption. Using preformed magic size wurtzite ZnSe nanowires as the source material and fragmenting them at higher reaction temperature, ZnSe nanorods with variable aspect ratios are designed. ...

Type-II nanorod heterostructure formation through one-step cation exchange

A novel one-step cation exchange approach has been developed to prepare ZnO-decorated ZnSe nanorods (ZnSe-ZnO NRs), a prototype type-II semiconductor nanoheterostructure. Because of the staggered band offset which promoted effective charge separation, the as-synthesized ZnSe-ZnO NRs exhibited remarkable photocatalytic activities under visible light illumination, demonstrating their promising potentials in relevant photoconversion applications.

Facile synthesis and optical properties of ultrathin Cu-doped ZnSe nanorods

Download options Please wait... Article information DOI https://doi.org/10.1039/C3CE41493K Article type Paper Submitted 28 Jul 2013 Accepted 03 Oct 2013 First published 08 Oct 2013 Download Citation CrystEngComm, 2013,15, 10495-10499 BibTex EndNote MEDLINE ProCite ReferenceManager RefWorks RIS Permissions Request permissions Facile synthesis and optical properties of ultrathin Cu-doped ZnSe nanorods S. Kou, T. Yao, X. Xu, R. Zhu, Q. Zhao and J. Yang, CrystEngComm, 2013, 15, 10495 DOI: 10.1039/C3CE41493K To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page. If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given. If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page. Read more about how to correctly acknowledge RSC content. Social activity Tweet Share Search articles by author Shufang Kou Tingting Yao Xiaofeng Xu Rui Zhu Qing Zhao Jian Yang

Nitrogen-Doped Graphene/ZnSe Nanocomposites: Hydrothermal Synthesis and Their Enhanced Electrochemical and Photocatalytic Activities

Nitrogen-doped graphene (GN) has great potential applications in many fields because doping with nitrogen can alter the electrical properties of graphene. It is still a challenge to develop a convenient method for synthesis of GN sheets. In this paper, we first report the synthesis of a nitrogen-doped graphene/ZnSe nanocomposite (GN-ZnSe) by a one-pot hydrothermal process at low temperature using graphene oxide nanosheets and [ZnSe](DETA)(0.5) nanobelts as precursors. ZnSe nanorods composed of ZnSe nanoparticles were found to deposit on the surface of the GN sheets. The results demonstrated that [ZnSe](DETA)(0.5) nanobelts were used not only as the source of ZnSe nanoparticles but also as the nitrogen source. Interestingly, it was found that the as-prepared nanocomposites exhibit remarkably enhanced electrochemical performance for oxygen reduction reaction and photocatalytic activities for the bleaching of methyl orange dye under visible-light irradiation. This facile and catalyst-free approach for depositing ZnSe nanoparticles onto the graphene sheets may provide an alternative way for preparation of other nanocomposites based on GN sheets under mild conditions, which show their potential applications in wastewater treatment, fuel cells, energy storage, nanodevices, and so on.

Synthesis, structure, and photoluminescence properties of ZnSSe alloy nanorods

ZnSSe alloy nanorods were prepared on gold (Au)-coated Si (100) substrates by the thermal evaporation of a mixture of ZnSe and ZnS powders. The nanorods were straight, 70–150 nm in width, and up to a few tens of micrometers in length. Transmission electron microscopy and X-ray diffraction indicated that the nanorods were ZnSSe single crystals with a wurtzite-type hexagonal close-packed structure. The photoluminescence measurements showed that the ZnSe nanorods had a strong emission band centered at approximately 500 nm in the blue-green region. The blue-green emission band corresponding to the deep-level emission of the ZnSSe nanorods showed no shift. On the other hand, a shoulder of the band in the blue region corresponding to the near-band edge (NBE) emission band shifted continuously from 466 nm to a lower wavelength region with increasing composition x in ZnSe 1− x S x from 0 to 0.41. The blue-green emission intensity of the ZnSSe nanrods also increased with increasing composition x. The enhancement of blue-green emission might be due to the increase in structural defects, such as dislocations and stacking faults in the nanorods.

Charge Carrier Dynamics for ZnO-decorated ZnSe Nanorods Prepare from Cation Exchange Process

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Chemical Synthesis, Structural Characterization, Optical Properties, and Photocatalytic Activity of Ultrathin ZnSe Nanorods

Ultrathin ZnSe nanorods in the cubic phase have been synthesized by the reaction of selenium and zinc oleate for 30 min at 240 °C. These nanorods showed an average diameter of 2.4 nm, which is much smaller than the Bohr size of bulk ZnSe. Thus, they exhibited a remarkable quantum size effect in terms of their optical properties. The formation of the ultrathin nanorods could be attributed to the oriented attachment mechanism, which was supported by the structure of the nanorods and the control experiments. The ultrathin nanorods were transferred into an aqueous solution by ligand exchange. The performance of these nanorods as a catalyst was examined, using the photodegradation of methyl orange as a model reaction. It was found that the ultrathin nanorods possessed better photocatalytic activities than conventional ones.