Nanoscale colloidal particles: Monolayer organization and patterning

Sato, Takahiro; Hasko, D. G.; Ahmed, Heba

doi:10.1116/1.589253

Cited by 147 publications

(67 citation statements)

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“…In most of the studies, the self-assembly scheme has been employed using the chemical interaction between the nanoparticles and the substrate. [9][10][11] This method is effective in achieving a dense layer of nanoparticles. However, the control of the particle density is difficult at submonolayer regime.…”

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confidence: 99%

Controlled surface distribution and luminescence of YVO4:Eu3+ nanophosphor layers

Khan

Haranath

Yadav

et al. 2008

Applied Physics Letters

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A method of dispersing YVO 4 : Eu quantum dots ͑QDs͒ as uniform two-dimensional ͑2D͒ layers with a high degree of homogeneity is presented. Annealing at 773 K resulted in coalescence of QDs to form nanoclusters with size of ϳ25 nm with an improved photoluminescence and ϳ80% transmittance at 800 nm. An efficient 5 D 0 -7 F 2 transition and lifetimes of ϳ1038 s for the characteristic Eu 3+ emission were observed. The absorption and emission peaks showed a slight blueshift, due to quantum-size effect, as compared to that for the bulk counterpart. Our method of 2D layer deposition is useful to enhance spectral response of the solar cells. © 2008 American Institute of Physics. ͓DOI: 10.1063/1.2973163͔ Quantum dots ͑QDs͒ have attracted much attention due to their potential applications for many high performance devices, 1 viz., the Si-solar cell 2 and QD based light emitting diodes.3 Chemically synthesized 4,5 QDs with precise size ͑Ͻ5 nm͒ control and a suitable organic/inorganic cap are currently available for many practical applications. 6 The QDs of phosphor materials could be even more interesting as they do not scatter light and show enhanced emission efficiencies 7 and radiative lifetime shortening. 8 The spatially distributed phosphor QDs can act as a thin layer having good optical transparency and high emission characteristics. Such a layer can be useful for increasing the power conversion efficiency of a solar cell. The objective of the present study is to fabricate highly transparent and luminescent two-dimensional ͑2D͒ layer using inorganic capped YVO 4 QDs that possess the advantages of quantum-size effect. Annealing treatments performed to the layers not only initiated the nanocluster formation but also provided a proper thermal encapsulation, adherence, and increased PL emission related efficiencies.In utilizing nanoparticles for device technology one of the fundamental issues is how to distribute nanoparticles uniformly over a substrate with a precise control of particle density. In most of the studies, the self-assembly scheme has been employed using the chemical interaction between the nanoparticles and the substrate.9-11 This method is effective in achieving a dense layer of nanoparticles. However, the control of the particle density is difficult at submonolayer regime. Moreover, special chemical treatments of the substrate surface are needed and the results are sensitive to local chemical environment with enhanced defect susceptibility.In this letter, we demonstrate the fabrication of uniformly distributed sodium hexametaphosphate ͑SHMP͒ capped YVO 4 : Eu nanophosphor layer with controlled particle density using the conventional spin-coating method followed by annealing treatment.It is well known that the OH − groups show significant luminescence quenching behavior for most of the inorganic QDs.12 Commonly, researchers synthesize YVO 4 : Eu nanophosphor by wet-chemical methods and protect the surface atoms by phosphate capping followed by redispersion in deionized water. This results in fully hydrat...

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mentioning

confidence: 99%

Controlled surface distribution and luminescence of YVO4:Eu3+ nanophosphor layers

Khan

Haranath

Yadav

et al. 2008

Applied Physics Letters

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“…Natural lithography [34], [35], is an extremely convenient route to developing nanofeatures over large areas for biological investigations. Colloidal gold particles, previously utilized in the development of single-electron devices [36], have emerged as a versatile method of producing nanometric features [37]. Every aspect of nanopatterning can be altered with respect to colloidal fabrication techniques, for example, colloidal and substrate materials, colloidal shape, size, and monolayer distribution which is reflected in feature pitch [33].…”

Section: Introductionmentioning

confidence: 99%

The Effects of Colloidal Nanotopography on Initial Fibroblast Adhesion and Morphology

Wood

Wilkinson

Curtis

2006

IEEE Trans.on Nanobioscience

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Abstract-Colloidal lithography offers a simple, inexpensive method of producing irregular nanotopographies, a pattern not easily attainable utilizing conventional serial writing processes. Colloids with 20-or 50-nm diameter were utilized to produce such an irregular topography and were characterized by calculating the percentage area coverage of particles. Interparticle and nearest neighbor spacing were also assessed for the individual colloids in the pattern. Two-way analysis of variance (ANOVA) indicated significant differences between the number of fibroblasts adhering to planar, 20-, and 50-nm-diameter colloidal topographies, the number of fibroblasts adhering to the substrates at the time intervals studied, namely 20 min, 1 h, and 3 h and significant interaction between time and topography on fibroblast adhesion

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“…This result also demonstrates an example application of EBL to pattern sub-10-nm structures. These nanoparticle structures can be used for single electron devices [17], [18].…”

Section: -Nm Ebl With Cold Developmentmentioning

confidence: 99%

High-Resolution Electron Beam Lithography and DNA Nano-Patterning for Molecular QCA

Sarveswaran

Lieberman

et al. 2005

IEEE Trans. Nanotechnology

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Abstract-Electron beam lithography (EBL) patterning of poly(methylmethacrylate) (PMMA) is a versatile tool for defining molecular structures on the sub-10-nm scale. We demonstrate lithographic resolution to about 5 nm using a cold-development technique. Liftoff of sub-10-nm Au nanoparticles and metal lines proves that cold development completely clears the PMMA residue on the exposed areas. Molecular liftoff is performed to pattern DNA rafts with high fidelity at linewidths of about 100 nm. High-resolution EBL and molecular liftoff can be applied to pattern Creutz-Taube molecules on the scale of a few nanometers for quantum-dot cellular automata.

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Nanoscale colloidal particles: Monolayer organization and patterning

Cited by 147 publications

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Controlled surface distribution and luminescence of YVO4:Eu3+ nanophosphor layers

Controlled surface distribution and luminescence of YVO4:Eu3+ nanophosphor layers

The Effects of Colloidal Nanotopography on Initial Fibroblast Adhesion and Morphology

High-Resolution Electron Beam Lithography and DNA Nano-Patterning for Molecular QCA

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