Synthetic SiO2 Opals

Ni, PG; Dong, Peng; Cheng, By; Li, XY; Zhang, Dz

doi:10.1002/1521-4095(200103)13:6<437::aid-adma437>3.0.co;2-8

Cited by 92 publications

(59 citation statements)

References 7 publications

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“…Due to difficulties in controlling the Stöber process, which consists of the hydrolysis and condensation of silicon alkoxide, fabricating uniform populations of SNPs in this size range has been challenging. Moreover, if the prepared colloids are not uniform in size, then additional purification processes using selection [26] or redispersion procedures [27] are required in order to improve the uniformity of the colloids.…”

Section: Introductionmentioning

confidence: 99%

Self-assembly of silica colloidal crystal thin films with tuneable structural colours over a wide visible spectrum

Gao

Rigout

Owens

2016

Applied Surface Science

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Colloidal crystal (CC) thin films that produce structural colours over a wide visible spectrum have been self-assembled from silica nanoparticles (SNPs) using a natural sedimentation method. A series of colloidal suspensions containing uniform SNPs (207-350 nm) were prepared using the Stöber method. The prepared silica suspensions were directly subjected to natural sedimentation at an elevated temperature. The SNPs were deposited under the force of gravity and selfassembled into an ordered array. The solid CC thin films produced structural colours over a wide visible spectrum from red to violet. Visual inspection and colorimetric measurements indicated that the structural colour of the CC thin film is tuneable by varying the SNPs diameters and the viewing angles. The closely packed face-centred cubic (fcc) structure of the CC thin film was confirmed using SEM imaging and was in agreement with the intense colour observed from the film surface.

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Section: Introductionmentioning

confidence: 99%

Self-assembly of silica colloidal crystal thin films with tuneable structural colours over a wide visible spectrum

Gao

Rigout

Owens

2016

Applied Surface Science

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“…Attributes of ordered particle assemblies, such as long-range order, high packing density, high surface-to-volume ratio, and reproducible shape and dimensions, are highly desirable in applications ranging from miniaturized sensors [1] and actuators [2,3], to nanoreactors [4], catalysts [5], 3-D crystals with complete photonic bandgaps [6][7][8][9], and high-density magnetic recording media. Methods such as colloidal crystallization [10][11][12][13] and template-directed synthesis [14][15][16] have been proposed for achieving particle organization.…”

Section: Introductionmentioning

confidence: 99%

One-, two-, and three-dimensional organization of colloidal particles using nonuniform alternating current electric fields

Docoslis

Alexandridis

2002

Electrophoresis

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We demonstrate here the use of nonuniform alternating current (AC) electric fields, generated by planar electrodes, for the organization of num-sized particles into one-, two-, and three-dimensional assemblies. The electrodes, with separations that vary from 35 to 300 num, are made of gold deposited on glass substrata. Latex, silica and graphite particles have been examined inside organic or aqueous media in order to illustrate the general applicability of the technique. Theoretical predictions of the particle response under the electric fields are experimentally confirmed for all the above particle/media combinations and can thus be used as a valuable design tool. The size and shape of the final structures are mainly dependent on the electrode shape and dimensions, but are also subject to the particle type and operating conditions. Particle organization in one dimension (strings) is achieved under conditions of positive or negative dielectrophoresis in the space between two energized electrodes. Two-dimensional particle organization (ordered, planar particles assemblies) was observed under conditions of negative dielectrophoresis, when quadrupole electrodes were employed. Moreover, when negative dielectrophoresis and stronger electric fields are applied (of the order of 50 kV(rms) m(-1)), three-dimensional, pyramid-like structures with a vertical dimension 1000-fold higher than that of the corresponding (planar) electrodes can be assembled. These 3-D structures can grow as free-standing assemblies, or inside templates etched in the substratum. The dielectrophoresis (DEP)-organized particle assemblies can subsequently be rendered permanent via the in situ fixing (cross-linking) of the individual particles.

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“…The mixture was stirred vigorously for 4 h to obtain a white turbid suspension, and the ambient temperature was kept at 30 0 C. Subsequently, nanospheres, separated from the mother liquid by centrifugation (3000 rpm), were purified and repeated with deionized water three times. Monodispersed nanospheres were obtained by partial aggregation of different sedimentation regions [27]. Finally, the high quality opal PhCs were fabricated by self-assembling processes with a thermal-assistant cell method [11].…”

Section: Methodsmentioning

confidence: 99%

Polarization Dependence in Optical Reflection and Transmission of Opal Photonic Crystals

Tuyen

2018

JST

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High-quality opal photonic crystals were fabricated by self-assembling of monodispersed SiO 2 nanospheres with a thermal-assistant cell method. The angle-and polarization-resolved optical reflection and transmission of an artificial opal were studied. A strong anisotropy in the intensity and the full width at half maximum of reflection and transmission spectra of the s-and p-polarized light was observed along the L-U (L-K) direction of the first Brillouin zone, and these differences become more pronounced in the vicinity U (K) point. The observed polarization anisotropy of optical properties is caused by symmetry characterization of polarized light and opal structure. The obtained results agree fairly well with calculated photonic band structure, which is also compared with predictions based on the group theory.

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Synthetic SiO2 Opals

Cited by 92 publications

References 7 publications

Self-assembly of silica colloidal crystal thin films with tuneable structural colours over a wide visible spectrum

Self-assembly of silica colloidal crystal thin films with tuneable structural colours over a wide visible spectrum

One-, two-, and three-dimensional organization of colloidal particles using nonuniform alternating current electric fields

Polarization Dependence in Optical Reflection and Transmission of Opal Photonic Crystals

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