Surfactant-assisted synthesis of semiconductor nanotubes and nanowires

Rao, C. N. R.; Govindaraj, A.; Deepak, Francis Leonard; Gunari, Nikhil; Nath, Manashi

doi:10.1063/1.1359145

Cited by 235 publications

(122 citation statements)

References 5 publications

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“…Table 2). This is in accordance with data published about Sm structures of dioctadecyldimethylammonium dodecylsulfate complex [34], a series of alkylammonium alkylsulfates [3,19,35], and disordered Sm phases in the mixtures of gemini surfactants with sodium alkylsulfates [18,19].…”

Section: Temperature -Dependent Measurementssupporting

confidence: 79%

“…The changes of corresponding total enthalpies and entropies, obtained from the heating cycle, (Figure 7b) point to the advanced organized phases with the increment of n 1 and less organized phases with the increment of n 2 , where the most stable compound is dimeric didodecylsulfate, i.e. N-bis [2- (3), and the most disordered is found to be three-tailed dodecylsulfate, i.e. tridodecylmethylammonium dodecylsulfate (5).…”

Section: Temperature -Dependent Measurementsmentioning

confidence: 99%

“…Design of different surfactant complexes and tailored functionalized assemblies opens opportunities for a wide range of scientific research and potential applications in commercial products; from pharmaceuticals [1] and template materials [2], to sensors and semiconductors [3]. There has been a strong interest for these compounds due to their liquid crystalline properties that make them comparable with biological structures and functions.…”

Section: Introductionmentioning

confidence: 99%

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Thermotropic phase transitions of catanionic dodecylsulfates with multi-charged and multi-tailed quaternary ammonium centers

et al. 2014

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Five novel anhydrous catanionic dodecylsulfates containing multi-charged and multi-tailed quaternary ammonium centers were synthesized and examined with light microscopy, differential scanning calorimetry and X-ray powder diffraction. This study is an attempt to explain the relationship between chemical structure, molecular architecture, phase transition characteristics and thermodynamics, and the nature of intermolecular interactions of the individual amphiphiles that ultimately lead to different mesomorphic product. All examined compounds are of typical layered structure at room temperature. The long spacing decreases linearly with the increase of either ionic head or n-dodecyl chain number. The thermal analysis of the examined multi-charged catanionics indicates thermotropic mesomorphism, whereas multi-tailed dodecylsulfates show only properties of soft crystals. Maltese crosses, oily streaks textures, stepped drops and fan-shaped textures affirmed the existence of various smectic mesophases at room and higher temperatures. Thermodynamically the most ordered compound is dimeric didodecylsulfate, and the most disordered is three-tailed dodecylsulfate. The addition of the new quaternary ammonium center or alkyl chain causes the increment of the lattice energy first, and it decreases by further changes in the structure. The temperatures of crystallization decrease by any mentioned addition.

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Section: Temperature -Dependent Measurementssupporting

confidence: 79%

Section: Temperature -Dependent Measurementsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Thermotropic phase transitions of catanionic dodecylsulfates with multi-charged and multi-tailed quaternary ammonium centers

et al. 2014

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“…[14] However, the synthesis of CdSe nanotubes has been met with limited success, and literature search indicated that only a few groups were able to generate tubular nanostructure of CdSe by templating against cylindrical micelles assembled from organic surfactants. [15] The lengths of nanotubes synthesized using such an approach were often restricted to the scale below 2±5 lm. The difficulty in selecting an appropriate surfactant to control the morphology also limits the extension of this method to other semiconductors.…”

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confidence: 99%

Direct Synthesis of Se@CdSe Nanocables and CdSe Nanotubes by Reacting Cadmium Salts with Se Nanowires

et al. 2003

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Templating against currently existing nanowires (or rods, belts) provides a straightforward and powerful route to greatly expand the diversity of materials that can be processed as uniform, one-dimensional (1D) nanostructures.[1] In one approach, the surfaces of nanowires could be directly coated (using a range of different methods) with conformal sheaths made of a different material to generate coaxial nanocables.[2]Subsequent removal of the nanowires would lead to the formation of nanotubes with well-controlled dimensions. In another approach, it has been demonstrated that single crystalline nanowires could serve as substrates for the epitaxial growth of another material to obtain coaxial, bilayer nanotapes characterized by sharp structural and compositional interfaces. [3] By carefully modulating the composition of reactant in sequential steps, it is also possible to fabricate semiconductor multiple-sheath nanowire heterostructures via epitaxial growth. [4] In a third approach (or the so-called template-engaged process), nanowires had been partially (e.g., on the surface only) or completely converted to other materials without changing the 1D morphology when they were reacted with appropriate chemical reagents under carefully controlled conditions.[5] The concept of this method was originally demonstrated by Lieber and co-workers, where they found that highly crystalline nanorods of metal carbides could be formed by reacting carbon nanotubes with the vapors of metal oxides or halides at elevated temperatures.[5a] A similar procedure (including the use of both vapor-and solution-phase reactions) was later exploited by many research groups to generate 1D nanostructures from a wealth of solid materials. These studies have also made it possible to incorporate a number of functions (e.g., luminescent, ferromagnetic, ferroelectric, piezoelectric, and superconducting) into an individual nanowire that will find applications in various areas. Here, we would like to add another example to this list, where uniform nanowires of t-Se were employed as chemical templates to generate Se@CdSe nanocables and then CdSe nanotubes. Figure 1 shows a schematic outline of the approach. The first step involved the synthesis of single-crystalline nanowires of t-Se via a sonochemical process.[ Note that the solubility of CdSeO 3 is sufficiently high at the refluxing temperature that it would not inhibit the formation of a dense CdSe sheath around each t-Se template via processes such as co-precipitation with CdSe. As the reaction was cooled down to room temperature, CdSeO 3 did precipitate out as nanoparticles decorating the surfaces of Se@CdSe nanocables. Fortunately, this unwanted byproduct could be effectively removed by washing the as-synthesized sample with hot water in the setting of filtration. Due to the relatively low melting point of t-Se (~217 C) as compared with CdSe nanoparticles, [8] the unreacted core of t-Se could be conveniently removed through evaporation (by heating at~230 C for a few minutes) to obtain the nanotube ...

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“…Chakraborty et al 31 have utilized a very simple approach to prepare nanodispersions (colloids) of CdS and HgS as well as their core-shell products and composites (co-colloids) in micellar solutions of the cationic surfactant CTAB. A relatively simple chemical method to synthesize CdS nanotubes by employing the surfactants AOT and Triton-X have been developed by Rao et al 32 To improve the application potential of these synthetic routes, further advancement is an important issue which a Department of Chemistry and Centre for Advanced Studies in Chemistry, Panjab needs to be considered through elaborating the tailoring of the nanocrystal morphology, elucidating the growth mechanism and optimizating the physical parameters for the generation of well defined nanostructures. In addition to interesting optical properties, CdS NPs with a diameter of less than 10 nm have become a recent topic of intense investigations towards their luminescent properties mainly due to their inherent broad PL spectrum.…”

Section: Introductionmentioning

confidence: 99%

The critical role of surfactants towards CdS nanoparticles: synthesis, stability, optical and PL emission properties

2013

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a Cadmium sulfide (CdS) nanoparticles (NPs), prepared by a convenient chemical precipitation method, have been characterized using techniques such as TEM, XRD, zeta potential, absorption and photoluminescence (PL) emission spectroscopy to establish the structure directing role of different cationic and anionic surfactants and their impact on the nanoparticles stabilization. In the synthesis of the CdS NPs, cadmium acetate and sodium sulfide, employed as starting reagents, were dissolved in aqueous solutions of different surfactants to study the effect of their structures on the nucleation, growth, optical and PL emission properties of the NPs. By varying the surfactant species, the CdS NPs have significantly different optical and PL emission properties despite being produced under similar reaction conditions. Depending on the surfactant structure, the growing CdS NPs were stabilized by the surfactants to different extents.For example, in the surfactant with the longest chain length (e.g. cetyltrimethylammonium bromide; CTAB), the CdS NPs were most stable, whereas using a surfactant with a smaller chain length i.e. DTAB, the NPs were unstable for even 1 h. On the other hand, anionic surfactants of even smaller chain lengths were able to stabilize the CdS NPs for quite long times. The generalized study of growth of spherical CdS NPs involves monitoring the kinetics during the progress of the reaction. Additionally, an interesting prominent effect of surfactant structure on the PL emission properties of the NPs has been established under identical reaction conditions.

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Surfactant-assisted synthesis of semiconductor nanotubes and nanowires

Abstract: Nanotubes and nanowires of CdSe and CdS have been obtained from solutions containing a surfactant such as Triton 100-X. They have been characterized by x-ray diffraction, electron microscopy, and optical spectroscopy.

Cited by 235 publications

References 5 publications

Thermotropic phase transitions of catanionic dodecylsulfates with multi-charged and multi-tailed quaternary ammonium centers

Thermotropic phase transitions of catanionic dodecylsulfates with multi-charged and multi-tailed quaternary ammonium centers

Direct Synthesis of Se@CdSe Nanocables and CdSe Nanotubes by Reacting Cadmium Salts with Se Nanowires

The critical role of surfactants towards CdS nanoparticles: synthesis, stability, optical and PL emission properties

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