Diameter Control and Photoluminescence of ZnO Nanorods from Trialkylamines

A novel solution method to control the diameter of ZnO nanorods is reported. Small diameter (2-3 nm) nanorods were synthesized from trihexylamine, and large diameter (50–80 nm) nanorods were synthesized by increasing the alkyl chain length to tridodecylamine. The defect (green) emission of the photoluminescence (PL) spectra of the nanorods varies with diameter, and can thus be controlled by the diameter control. The small ZnO nanorods have strong green emission, while the large diameter nanorods exhibit a remarkably suppressed green band. We show that this observation supports surface oxygen vacancies as the defect that gives rise to the green emission.

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SYNTHESIS AND CHARACTERIZATION OF ZnO NANORODS AND NANOWIRES USING PVP AS CAPPING

International Journal of Nanoscience ◽

10.1142/s0219581x09006183 ◽

2009 ◽

Vol 08 (03) ◽

pp. 285-287 ◽

Cited By ~ 1

Author(s):

M. ESKANDARI ◽

V. AHMADI ◽

Sh. AHMADI

Keyword(s):

Solution Method ◽

Zno Nanorods ◽

Green Emission ◽

Zno Nanowires ◽

X Ray Diffraction ◽

X Ray ◽

Chemical Solution Method ◽

Air Atmosphere ◽

20 Nm

In this study, ZnO nanowires are synthesized via ZnO nanorods at low temperature by using zinc acetate dehydrate and polyvinylpyrrolidone as precursor and capping, respectively. We use chemical solution method for synthesis of ZnO nanowires. Samples are characterized by means of scanning electron microscopy and X-ray diffraction. First, the nanorods are prepared at 300°C temperature, and then they are put into the furnace under air atmosphere at 450°C for 2 h. It is observed that nanowires with 20 nm diameter are produced. Photoluminescence spectra of nanorods and nanowires are compared. It shows that intensity of ultraviolet peak in the nanowires decreases but in contrast the intensity of green emission part increases. This is because, the surface effects such as oxygen vacancies increase in the structures of ZnO .

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Morphology Control and Photoluminescent Properties of Bundled ZnO Nanorods Array Based on Silicon Nanoporous Pillar Array

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.727.598 ◽

2017 ◽

Vol 727 ◽

pp. 598-603

Author(s):

Ling Li Wang ◽

Shi Quan Feng ◽

Hai Yan Wang

Keyword(s):

Room Temperature ◽

Oxygen Vacancies ◽

Thermal Evaporation ◽

Growth Parameters ◽

Zno Nanorods ◽

Green Emission ◽

Thermal Evaporation Method ◽

Violet Emission ◽

Pillar Array ◽

Nanorods Array

A silicon nanoporous pillar array (Si-NPA) is a silicon hierarchical structure with regularly patterned surface morphology. An array of bundled ZnO nanorods was grown based on Si-NPA by a catalyst-free thermal evaporation method. The morphology of ZnO/Si-NPA was found to be greatly affected by the growth parameters such as the grown temperature and the ratio nitrogen and oxygen. The room-temperature photoluminescence (PL) spectrum of ZnO/Si-NPA showed a violet emission at ∼410 nm and a blue-green emission around 500 nm, which were attributed to the PL of Si-NPA substrate and oxygen vacancies of ZnO, respectively. The results indicated that ZnO/Si-NPA is a promising optical material.

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Differences in the brain stem terminations of large- and small-diameter vestibular primary afferents

Journal of Neurophysiology ◽

10.1152/jn.1995.74.3.1362 ◽

1995 ◽

Vol 74 (3) ◽

pp. 1362-1366 ◽

Cited By ~ 9

Author(s):

J. A. Huwe ◽

E. H. Peterson

Keyword(s):

Brain Stem ◽

Large Diameter ◽

Small Diameter ◽

Movement Control ◽

Three Dimensions ◽

Significant Shift ◽

Axon Diameter ◽

Vestibular Complex ◽

The Brain ◽

Adjacent Brain

1. We visualized the central axons of 32 vestibular afferents from the posterior canal by extracellular application of horseradish peroxidase, reconstructed them in three dimensions, and quantified their morphology. Here we compare the descending limbs of central axons that differ in parent axon diameter. 2. The brain stem distribution of descending limb terminals (collaterals and associated varicosities) varies systematically with parent axon diameter. Large-diameter afferents concentrate their terminals in rostral regions of the medial/descending nuclei. As axon diameter decreases, there is a significant shift of terminal concentration toward the caudal vestibular complex and adjacent brain stem. 3. Rostral and caudal regions of the medial/descending nuclei have different labyrinthine, cerebellar, intrinsic, commissural, and spinal connections; they are believed to play different roles in head movement control. Our data help clarify the functions of large- and small-diameter afferents by showing that they contribute differentially to rostral and caudal vestibular complex.

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Influence of alkyl chain length on the action of acetylated monoglycerides as plasticizers for poly (vinyl chloride) food packaging film

Food Packaging and Shelf Life ◽

10.1016/j.fpsl.2020.100619 ◽

2021 ◽

Vol 27 ◽

pp. 100619

Author(s):

Chang Woo Kwon ◽

Pahn-Shick Chang

Keyword(s):

Chain Length ◽

Vinyl Chloride ◽

Food Packaging ◽

Alkyl Chain ◽

Alkyl Chain Length ◽

Packaging Film ◽

Poly Vinyl Chloride

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Silver Nanoparticles Stabilized with Phosphorus-Containing Heterocyclic Surfactants: Synthesis, Physico-Chemical Properties, and Biological Activity Determination

Nanomaterials ◽

10.3390/nano11081883 ◽

2021 ◽

Vol 11 (8) ◽

pp. 1883

Author(s):

Martin Pisárčik ◽

Miloš Lukáč ◽

Josef Jampílek ◽

František Bilka ◽

Andrea Bilková ◽

...

Keyword(s):

Silver Nanoparticles ◽

Biological Activity ◽

Zeta Potential ◽

Chain Length ◽

Alkyl Chain ◽

Chemical Properties ◽

Alkyl Chain Length ◽

Microbial Pathogens ◽

Physico Chemical ◽

Phosphorus Containing

Phosphorus-containing heterocyclic cationic surfactants alkyldimethylphenylphospholium bromides with the alkyl chain length 14 to 18 carbon atoms were used for the stabilization of silver nanodispersions. Zeta potential of silver nanodispersions ranges from +35 to +70 mV, which indicates the formation of stable silver nanoparticles (AgNPs). Long-chain heptadecyl and octadecyl homologs of the surfactants series provided the most intensive stabilizing effect to AgNPs, resulting in high positive zeta potential values and smaller diameter of AgNPs in the range 50–60 nm. A comparison with non-heterocyclic alkyltrimethylphosphonium surfactants of the same alkyl chain length showed better stability and more positive zeta potential values for silver nanodispersions stabilized with heterocyclic phospholium surfactants. Investigations of biological activity of phospholium-capped AgNPs are represented by the studies of antimicrobial activity and cytotoxicity. While cytotoxicity results revealed an increased level of HepG2 cell growth inhibition as compared with the cytotoxicity level of silver-free surfactant solutions, no enhanced antimicrobial action of phospholium-capped AgNPs against microbial pathogens was observed. The comparison of cytotoxicity of AgNPs stabilized with various non-heterocyclic ammonium and phosphonium surfactants shows that AgNPs capped with heterocyclic alkyldimethylphenylphospholium and non-heterocyclic triphenyl-substituted phosphonium surfactants have the highest cytotoxicity among silver nanodispersions stabilized by the series of ammonium and phosphonium surfactants.

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