Structural engineering of nanoporous anodic alumina funnels with high aspect ratio

Santos, Abel; Formentı́n, Pilar; Pallarès, Josep; Ferré‐Borrull, Josep; Marsal, Lluís F.

doi:10.1016/j.jelechem.2011.02.005

Cited by 53 publications

(44 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Because the PAA films composed of cylindrical pore channels, the transmittance for two-and three-tiered PAA films may be predominantly dependent on the diffusive reflection from the tier interface with different pore intervals. In particular, both the two-and three-tiered PAA films exhibited a unique transmittance decline near 400 nm in wavelength (indicated by the vertical dashed lines in Figure 8), thus producing two transmittance plateaus of 40% in the wavelength region of 350-400 nm and of 55% above 500 nm, which can be attributed to a special absorbance from the multi-tiered nanostructure that is distinct from the conventional single-tiered PAA films 23 and freestanding PAA membranes with periodical branches. 34,35 Interestingly, both two-tiered and three-tiered PAA films exhibit similar spectra.…”

Section: Ecs Journal Of Solidmentioning

confidence: 99%

“…Alternatively, several studies reported another type of 3D porous alumina films that consisted of two to four segments with stepwise changes in pore diameters. [20][21][22][23] For instance, Krishnan et al reported a PAA film whose pore diameters changed in a stepwise manner from 55 to 85 nm or vice z E-mail: chusongz@iwate-u.ac.jp versa, via two-step anodization in oxalic and phosphoric acid solutions, assisted by an interface lithography process.20 Ho et al fabricated a multi-tiered branched PAA film consisting of an array of big pores branching into 2-4 smaller pores in succeeding tiers, by sequentially stepping down the anodization potential while etching the barrier layer after each step.22 Meng et al 24,25 and Zaraska et al 26 attempted to produce hierarchical PAA films with root-like pore channels by reducing the anodizing potential by a factor of 1/ √ n(n = 2, 3) in an oxalic acid solution from 72 V to 50 V 24 or from 60 V to 30 V 26 to increase the pore cell numbers. However, most of the previous works could only fabricate PAA films with decreasing pore size.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Facile Fabrication of Ordered Multi-Tiered Hierarchical Porous Alumina Nanostructures with Multiple and Fractional Ratios of Pore Interval toward Multifunctional Nanomaterials

Kure‐Chu

Osaka

Yashiro

et al. 2016

ECS J. Solid State Sci. Technol.

View full text Add to dashboard Cite

Conventional nanoporous anodic alumina films are composed of one-tiered pore arrays that can only render to one-dimensional (1D) nano-structures if they are used as nano-templates. Hence, three-dimensional (3D) nanoporous alumina films are desirable to dramatically increase the variety of nanostructures by template-fabrication for various potentially enhanced performances. Herein we report a facile approach to fabricate a variety of ordered multi-tiered 3D porous alumina nanostructures with multiple integer (m = 2, 3, 4, 5, 7, 9, and 10) and fractional ratios (n = 1/2 and 1/3) of the pore interval and pore diameter among different tiers on ITO/glass and Al sheets. The multi-tiered nanostructures and the pore interval ratios of the neighboring tiers can be accurately and independently controlled by a tailored multiple stepwise anodization, successively in appropriate acidic electrolytes of sulfuric, oxalic, and/or phosphoric solutions at designed voltages of 15-180 V, corresponding to the multiple or fractional ratios of pore interspacing. Moreover, the multi-tiered hierarchical nanoporous alumina films on ITO/glass substrates exhibited a lower transmittance compared with that of the single-tiered films with ordered cylindrical pores, which can be attributed to the diffusive reflection from the tier interface with different pore intervals. In past decades, porous anodic alumina (PAA) films have attracted considerable attention in both scientific and technical applications owing to the unique geometric structure with ordered hexagonal arrays of cylindrical nano-pores, similar to a nano-scaled honeycomb.1-4 In recent years, PAA nanostructures have been extensively used as a core nanotemplate to fabricate various one-dimensional (1D) functional nanostructures, such as nanowires 5-9 and nanotubes, 10-14 which can be used in a wide variety of applications including DNA and gas sensors, electro-chromic devices, light-emitting diodes, field emitters, super-capacitors, nano-electronic devices, and nano-generators. In order to facilitate the functional integration of nanostructures, template synthesis is evolving towards the fabrication of nanomaterials with increasing geometric complexity, i.e., going from two-dimensional (2D) to three-dimensional (3D) nanostructures. However, a major challenge in obtaining 3D nanostructures is the prior fabrication of ordered 3D nanoporous template with independently controllable size, spacing, position, and shape of the pore arrays as required for various applications.Many studies so far have attempted to fabricate various porous alumina nanostructures with variable pore diameters using tailored anodization methods assisted by chemical dissolution at different operating temperatures. Lee at al. reported first on the fabrication of ordered PAA films with variable pore diameters from 40 to 59 nm by combining mild anodization (MA) with hard anodization (HA) in oxalic acidic electrolytes. 15 This approach was further developed to achieve 3D PAA films with shaped pore geometries in periodic...

show abstract

Section: Ecs Journal Of Solidmentioning

confidence: 99%

mentioning

confidence: 99%

Facile Fabrication of Ordered Multi-Tiered Hierarchical Porous Alumina Nanostructures with Multiple and Fractional Ratios of Pore Interval toward Multifunctional Nanomaterials

Kure‐Chu

Osaka

Yashiro

et al. 2016

ECS J. Solid State Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…These alternate anodization steps were carried out in prepatterned substrates by imprint lithography, as well as interference lithography, with similar results (Krishnan and Thompson, 2007). Alternate anodization steps also are applied to fabricate funnel-like, modulated nanochannels of anodic alumina (Santos et al, 2011b;Li et al, 2012;Figure 1.8c). This methodology implies the systematic etching of alumina nanochannels after each anodization step so that the pores widen at each step to achieve a conical structure.…”

Section: Modulation Controlled By Alternate Anodization Stepsmentioning

confidence: 99%

Electrochemical methods for template-assisted synthesis of nanostructured materials

Prida

Vega

Garcı́a

et al. 2015

Magnetic Nano- And Microwires

View full text Add to dashboard Cite

“…Reprinted with permission from [30]. Copyright (2013) American Chemical Society fabricated under mild anodization conditions in oxalic is rather higher than that of p-AAO produced in sulphuric, phosphoric and malonic acids for mild or hard anodization conditions [16,132].…”

Section: Photoluminescence-based Applications Of Porous Anodic Aluminmentioning

confidence: 99%

Optical Properties of Nanoporous Anodic Alumina and Derived Applications

et al. 2015

Self Cite

View full text Add to dashboard Cite

Inexpensive formation of periodically ordered structures with periodicities and feature sizes lower than 100 nm has triggered a vast amount or research in recent years. Of particular interest in nanotechnology is the nanoporous alumina, which can be produced with a self-organized arrangement of pores in the adequate anodization conditions. Most of the interest of this material is based in its outstanding physical and chemical and properties, and more specifically in its optical properties. The interaction of light with the nanostructured porous alumina gives rise to a wealth of optical properties that have their interest both in research level and also in application. In this work we aim at giving an extensive review of the published research on the optical properties of nanoporous alumina. The review will account for the different studied optical properties of this material such as the existence of a photonic stop band originated from its quasi-random nanostructure, the interferometric and light guiding properties that can be applied to biosensing, the structure nanoengineering to achieve more complex photonic behaviour such as distributed-Bragg reflectors or rugate filters, and the photoluminescence properties. In a second part, a summary of the different applications proposed on the basis of these properties, such as in biotechnology or energy will be given. IntroductionAmong the different features and properties of porous anodic alumina (p-AAO), its optical properties are of special interest and have been the subject of very intensive research. The interaction of light with p-AAO can be analyzed from different points of view: the material interaction, the porous structure interaction or the relation of geometrical features of the nanostructure (periodicity or quasi-periodicity, distance

show abstract

Structural engineering of nanoporous anodic alumina funnels with high aspect ratio

Cited by 53 publications

References 30 publications

Facile Fabrication of Ordered Multi-Tiered Hierarchical Porous Alumina Nanostructures with Multiple and Fractional Ratios of Pore Interval toward Multifunctional Nanomaterials

Facile Fabrication of Ordered Multi-Tiered Hierarchical Porous Alumina Nanostructures with Multiple and Fractional Ratios of Pore Interval toward Multifunctional Nanomaterials

Electrochemical methods for template-assisted synthesis of nanostructured materials

Optical Properties of Nanoporous Anodic Alumina and Derived Applications

Contact Info

Product

Resources

About