Effects of pH and ionic strength on the self-assembly of silica colloids to opaline photonic structures

Piret, F.; Su, Bao Lian

doi:10.1016/j.cplett.2008.04.036

Cited by 30 publications

(34 citation statements)

References 29 publications

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“…The reflective properties of samples have been studied to probe the PBG behavior of the samples. The fractional bandwidth of the samples (Dk/k p ) [21,65] has been calculated to assess their quality (structural organization and defect density).…”

Section: Introductionmentioning

confidence: 99%

Rutile TiO2 inverse opal with photonic bandgap in the UV–visible range

Piret

Léonard

et al. 2010

Journal of Colloid and Interface Science

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Section: Introductionmentioning

confidence: 99%

Rutile TiO2 inverse opal with photonic bandgap in the UV–visible range

Piret

Léonard

et al. 2010

Journal of Colloid and Interface Science

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“…The organization of the doped crosslinked films will result from the combined effect of the crosslinker precursors and the dyes: while the pH for the casting solution is still about constant due to the weak acidity of the hydrolised species, we have increased the ionic force of the solution and the overall volatility of the solvent (ethanol is released during TEOS hydrolysis), both parameters that have been reported to increase the degree of order in selfassembled opal films [18,19]. In our samples, however, the quality of the cast crosslinked films is always poorer than both the pure particles and simple crosslinked sample.…”

Section: Crosslinked Solid Film Propertiesmentioning

confidence: 97%

“…High zeta potentials seem to favor the formation of more regular crystals and the same does high solvent polarity, while unexpectedly a high ionic strength has been found to favor close packing by shielding particle repulsive interactions [18]. The effect of pH and ionic strength on the packing of charged spheres has been studied in the literature for simple model compounds (such as NaCl) especially for rigid silica particles [19], and also the progressive neutralization with NaOH for PS-MAA particles modulating their aggregation behavior [13].…”

Section: Introductionmentioning

confidence: 94%

“…In the case of rigid silica particles, pH between 1.5 and 3.5 (small fraction of ionized silanol groups) or the presence of solvated ions screening the excess of charge at low pH or at pH around 9e10 are known to help the opal formation while high electrostatic repulsion and an excess of solvated ions disturb the surface tension and the capillary forces causing sedimentation to a disordered solid [18].…”

Section: Introductionmentioning

confidence: 99%

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Effect of some industrial dyes on the self-assembly of polymeric opals based on core-shell nanoparticles

et al. 2015

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“…Δλ is the full width at half maximum and λ is the position of the stop band. The height of the reflectance peak (h(%)) and the fractional band width (Δλ/λ) of these samples were be compared to assess their quality: a low reflectance peak and a peak broadening effect can be attributed to disorder within the structure [16,17]. A higher reflectance peak and a lower value for the fractional band width correspond to a better quality photonic crystal film because it indicates that ZnO materials have grown more evenly on the SiO 2 spheres and in the interstitial space of the SiO 2 photonic crystal template.…”

Section: Optical Characterizationmentioning

confidence: 99%

Influence of deposition time on the morphology and optical properties of SiO2-ZnO composite photonic crystals

et al. 2011

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SiO 2 photonic crystal were successfully prepared by vertical deposition and then used as a template to fabricate SiO 2 -ZnO composite photonic crystals on ITO substrates by electrodeposition and subsequent calcination. A number of different deposition times were used. The morphologies of the silica opals and SiO 2 -ZnO composite photonic crystals were investigated by scanning electron microscopy. It was found that ZnO particles grew randomly on the surfaces of the silica spheres when the deposition time was short. As the deposition time was increased, the ZnO particles grew evenly on the surfaces of the silica spheres so that the interstitial space of the silica template was filled with ZnO particles. Reflectance spectra of the SiO 2 -ZnO composite crystals revealed that all of the fabricated photonic crystals exhibit a photonic band gap in the normal direction. [7]. However, the fabrication of 3-D opal photonic crystals is still a technical challenge, because many kinds of intrinsic defects such as plane defects, line defects, and dot defects appear during self-assembly. During self-assembly, surface charge *Corresponding author (email: fengbx@lzu.edu.cn) on colloidal spheres is a key element in successfully producing high quality colloidal crystals. Some scientists had fabricated SiO 2 photonic crystals with high quality by enhancing surface charge on SiO 2 spheres via modification with succinic acid [8]. In this work, vertical deposition was chosen as the self-assembly method to fabricate SiO 2 photonic crystal templates as it provides a relatively simple approach to obtaining high quality opal films.Silica or polymer opals do not have a full band gap because of their low refractive index (1.47 for silica). However, these opals are calculated to have a photonic band gap in the (111) direction, so opal-based materials, such as composite photonic crystals with different fillings and inverted opals [9][10][11], are of interest. ZnO is an important semiconductor material with a wide electronic band gap, which has a higher refractive index (2.1) than other materials. As a result, an increasing number of SiO 2 -ZnO composite photonic crystals have been fabricated by a range of methods [12,13].In this work, SiO 2 -ZnO composite photonic crystals were fabricated by electrodeposition followed by calcination at

show abstract

Effects of pH and ionic strength on the self-assembly of silica colloids to opaline photonic structures

Cited by 30 publications

References 29 publications

Rutile TiO2 inverse opal with photonic bandgap in the UV–visible range

Rutile TiO2 inverse opal with photonic bandgap in the UV–visible range

Effect of some industrial dyes on the self-assembly of polymeric opals based on core-shell nanoparticles

Influence of deposition time on the morphology and optical properties of SiO2-ZnO composite photonic crystals

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