Thin film photonic crystals: synthesis and characterisation

McLachlan, Martyn A.; Johnson, Nigel P.; Rue, R.M. De La; McComb, David W.

doi:10.1039/b310759k

Cited by 104 publications

(86 citation statements)

References 28 publications

(17 reference statements)

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“…Thin films typically have an upper threshold thickness, beyond which "channel" type cracking occurs (46,47). Noticeably, sol-gel SiO 2 films tend to fracture at a threshold thickness of approximately 0.5 μm (10× smaller than the coassembled films), and colloidal crystals of similar thickness invariably crack (unless modified in some way) (6,11,24,25,(28)(29)(30)(31) (Fig. 2A).…”

Section: Resultsmentioning

confidence: 99%

“…The use of these self-assembly processes to form large-area colloidal crystal films has very typically resulted in the formation of cracks, domain boundaries, colloid vacancies, and other defects. Efforts have also been made to inhibit cracking (23) and control domain orientation of colloidal crystal films through changes of evaporative deposition conditions (20,24), particle presintering (25), and deposition onto topologically patterned substrates (26). In the second step, sol-gel solutions have been used as matrix precursors for the syntheses of porous oxide materials, such as SiO 2 , TiO 2 , and Al 2 O 3 (1-5).…”

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confidence: 99%

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Assembly of large-area, highly ordered, crack-free inverse opal films

Hatton

Mishchenko

Davis

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

498

578

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Whereas considerable interest exists in self-assembly of well-ordered, porous “inverse opal” structures for optical, electronic, and (bio)chemical applications, uncontrolled defect formation has limited the scale-up and practicality of such approaches. Here we demonstrate a new method for assembling highly ordered, crack-free inverse opal films over a centimeter scale. Multilayered composite colloidal crystal films have been generated via evaporative deposition of polymeric colloidal spheres suspended within a hydrolyzed silicate sol-gel precursor solution. The coassembly of a sacrificial colloidal template with a matrix material avoids the need for liquid infiltration into the preassembled colloidal crystal and minimizes the associated cracking and inhomogeneities of the resulting inverse opal films. We discuss the underlying mechanisms that may account for the formation of large-area defect-free films, their unique preferential growth along the 〈110〉 direction and unusual fracture behavior. We demonstrate that this coassembly approach allows the fabrication of hierarchical structures not achievable by conventional methods, such as multilayered films and deposition onto patterned or curved surfaces. These robust SiO 2 inverse opals can be transformed into various materials that retain the morphology and order of the original films, as exemplified by the reactive conversion into Si or TiO 2 replicas. We show that colloidal coassembly is available for a range of organometallic sol-gel and polymer matrix precursors, and represents a simple, low-cost, scalable method for generating high-quality, chemically tailorable inverse opal films for a variety of applications.

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Assembly of large-area, highly ordered, crack-free inverse opal films

Hatton

Mishchenko

Davis

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

498

578

View full text Add to dashboard Cite

show abstract

“…1f), which is characteristic of opal systems prepared by sedimentation or drying of colloidal suspensions. [6][7][8][9] In the other scenario the radially symmetric material flow during compression forces domain alignment, resulting in a ''super domain'' as large as the entire 15 cm sample with a macroscopic radial director profile (n outwards, Fig. 1g).…”

mentioning

confidence: 98%

“…[1][2][3][4][5] However, the conventional methods suffer from multiple drawbacks, with cracking and polycrystallinity [6][7][8][9] leading to degradation of the optical properties of these photonic crystals through, e.g., scattering. These special difficulties in 3D photonic crystal fabrication have hindered the utilization of the technology in commercial applications, and such photonic information technology [10] is still in its infancy.…”

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confidence: 99%

Shear‐Induced Organization in Flexible Polymer Opals

et al. 2008

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Synthesis of 3D opaline photonic crystals has developed into a standard procedure during the last decade. [1][2][3][4][5] However, the conventional methods suffer from multiple drawbacks, with cracking and polycrystallinity [6][7][8][9] leading to degradation of the optical properties of these photonic crystals through, e.g., scattering. These special difficulties in 3D photonic crystal fabrication have hindered the utilization of the technology in commercial applications, and such photonic information technology [10] is still in its infancy. Clearly there is a need for industrial-scale, high-yield methods for producing functional photonic crystals. A novel cost-effective large-scale technique to produce flexible opals through shear-ordering during compression, utilizing a core/shell approach based on polymers, has recently been developed [11,12] and further demonstrated to have possible applications, e.g., sensor, security, and structural color applications. [13] In this Communication we present a key analysis of the 3D rheologically derived properties of shear-ordered opaline thinfilm photonic crystals using optical tracking of the strain-induced anisotropy. Probing UV-surface diffraction combined with band-gap measurements reveals a complete picture of the unit cell changes under strain. The results demonstrate that our polymer opals consist of a coherently ordered ''super-domain'' characterized by a radial director vector and show anisotropic photonic behavior depending on the relative vectorial orientation of strain and director.Shear-ordering of colloidal suspensions has been studied extensively in recent years. [14][15][16][17] In these systems the crystal ordering is dependent on both the applied shear profile and the strength of shear, and with suitable conditions long-range ordering is achieved, possibly with some dislocations or stacking faults. Our approach relies on the compression-induced shear-flow ordering of core/shell polymer particles resulting in highly-ordered solid photonic crystals with spectacular structural color features (Fig. 1a). We start with precursor core/shell particles composed of a polystyrene-polymethylmethacrylate (PS-PMMA) core and polyethylacrylate (PEA) shell. The detailed precursor preparation is described elsewhere.[11] By uniaxially compressing the precursor powder between two heated plates (Fig. 1b), we create a viscous shear flow in the polymer melt forcing the spheres to assemble into an fcclattice. The resulting structure formed here is a circular thin (ca. 300 mm) film disk (diameter 15 cm) of low-refractiveindex-contrast fcc-crystal, with the PS-PMMA cores forming the lattice and the PEA filling the interstitial sites. In this photonic crystal film the (111) planes are oriented parallel to the compression plates. [11][12][13] The (111)-plane resonance wavelength can be tuned by varying the precursor PS-PMMA particle size, and the sample can be doped with nanoparticles leading to interesting photonic behavior. [18] In this paper we show results obtained from opals us...

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“…This work made use of polystyrene-based PhCs which were fabricated on glass substrates using capillary growth of 230 nm diameter polystyrene spheres [14]. 5 nm diameter mono-dispersed nano-gold colloid (with particle diameters in the range of 3.5 to 6.…”

Section: Nano-gold Colloid Infiltration Techniquementioning

confidence: 99%

Preparation and properties of gold-infiltrated polystyrene photonic crystals

Khokhar

Rahman

Johnson

2011

Journal of Physics and Chemistry of Solids

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Artificial opals are an important class of photonic crystals that can be used for a number of different applications. Here we describe a simple process for doping the voids of polystyrene-based three-dimensional photonic crystals with metal nanoparticles. Our demonstration made use of nano-gold colloids but similar techniques can be used for incorporating nano-particles of other metals inside the interstices of self-assembled opals. A particularly attractive feature of our technique is that it allows thick opal films to be infiltrated easily with capillary forces transporting the active dopant inside the microporous material. The infiltration technique is described followed by a description of scanning electron microscopy performed on infiltrated samples. Gold nano-pillars with diameters of 35 nm have been observed between the domains and also on (111) plane. Results of optical reflection experiments carried out on infiltrated opals are described next which show the presence of surface plasmon resonance bands.

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Thin film photonic crystals: synthesis and characterisation

Cited by 104 publications

References 28 publications

Assembly of large-area, highly ordered, crack-free inverse opal films

Assembly of large-area, highly ordered, crack-free inverse opal films

Shear‐Induced Organization in Flexible Polymer Opals

Preparation and properties of gold-infiltrated polystyrene photonic crystals

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