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Nanoscale characterization of local structures and defects in photonic crystals using synchrotron-based transmission soft X-ray microscopy.

Nho HW, Kalegowda Y, Shin HJ, Yoon TH - Sci Rep (2016)

Bottom Line: Micro-domains of face-centered cubic (FCC (111)) and hexagonal close-packed (HCP (0001)) structures were dominantly found in PS-based PCs, while point and line defects, FCC (100), and 12-fold symmetry structures were also identified as minor components.Additionally, in situ observation capability for hydrated samples and 3D tomographic reconstruction of TXM images were also demonstrated.This soft X-ray full field TXM technique with faster image acquisition speed, in situ observation, and 3D tomography capability can be complementally used with the other X-ray microscopic techniques (i.e., scanning transmission X-ray microscopy, STXM) as well as conventional characterization methods (e.g., electron microscopic and optical/fluorescence microscopic techniques) for clearer structure identification of self-assembled PCs and better understanding of the relationship between their structures and resultant optical properties.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, College of Natural Sciences, Hanyang University, Seoul, 04763, Republic of Korea.

ABSTRACT
For the structural characterization of the polystyrene (PS)-based photonic crystals (PCs), fast and direct imaging capabilities of full field transmission X-ray microscopy (TXM) were demonstrated at soft X-ray energy. PS-based PCs were prepared on an O2-plasma treated Si3N4 window and their local structures and defects were investigated using this label-free TXM technique with an image acquisition speed of ~10 sec/frame and marginal radiation damage. Micro-domains of face-centered cubic (FCC (111)) and hexagonal close-packed (HCP (0001)) structures were dominantly found in PS-based PCs, while point and line defects, FCC (100), and 12-fold symmetry structures were also identified as minor components. Additionally, in situ observation capability for hydrated samples and 3D tomographic reconstruction of TXM images were also demonstrated. This soft X-ray full field TXM technique with faster image acquisition speed, in situ observation, and 3D tomography capability can be complementally used with the other X-ray microscopic techniques (i.e., scanning transmission X-ray microscopy, STXM) as well as conventional characterization methods (e.g., electron microscopic and optical/fluorescence microscopic techniques) for clearer structure identification of self-assembled PCs and better understanding of the relationship between their structures and resultant optical properties.

No MeSH data available.


Related in: MedlinePlus

TXM images of (A) double and (C) triple layered (100) face FCC structures of PCs (scale bar of 1 μm). CAD drawn model structures of (B) double and (D) triple layers.
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f2: TXM images of (A) double and (C) triple layered (100) face FCC structures of PCs (scale bar of 1 μm). CAD drawn model structures of (B) double and (D) triple layers.

Mentions: In addition to close-packed FCC (111) and HCP (0001) structures, (100) face of FCC and 12-fold symmetric structures were also found at the edge of the colloidal PCs or between colloidal crystal domains (Figs 2 and 3). Because of uncontrolled drying process in self-assembly growth, there could be fluctuations in the particle concentration or drying rate, which may induce structural changes in meniscus of colloidal solutions23. In Fig. 2, square lattice with an angle of 90° between the two particles are shown as the (100) face of FCC structures. TXM images of the double and triple layered (100) face of FCC are shown in Fig. 2A,C, and the model structures of those are illustrated in Fig. 2B,D. The circles with grey-, red-, and blue- color represents the first, second, and third layer, respectively, and the unit cell is marked as red dash square. In the double layered structure, shown in Fig. 2A, the unit cell length is about 720 nm, therefore the structure resembles FCC (100) face. The theoretical unit cell length (inter-particle distance in same plane) of FCC is about 707 nm, √2 times diameter of the particle. In the triple layered structure shown in Fig. 2C, the darkest spots represent the overlap of the first and third layer.


Nanoscale characterization of local structures and defects in photonic crystals using synchrotron-based transmission soft X-ray microscopy.

Nho HW, Kalegowda Y, Shin HJ, Yoon TH - Sci Rep (2016)

TXM images of (A) double and (C) triple layered (100) face FCC structures of PCs (scale bar of 1 μm). CAD drawn model structures of (B) double and (D) triple layers.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4834481&req=5

f2: TXM images of (A) double and (C) triple layered (100) face FCC structures of PCs (scale bar of 1 μm). CAD drawn model structures of (B) double and (D) triple layers.
Mentions: In addition to close-packed FCC (111) and HCP (0001) structures, (100) face of FCC and 12-fold symmetric structures were also found at the edge of the colloidal PCs or between colloidal crystal domains (Figs 2 and 3). Because of uncontrolled drying process in self-assembly growth, there could be fluctuations in the particle concentration or drying rate, which may induce structural changes in meniscus of colloidal solutions23. In Fig. 2, square lattice with an angle of 90° between the two particles are shown as the (100) face of FCC structures. TXM images of the double and triple layered (100) face of FCC are shown in Fig. 2A,C, and the model structures of those are illustrated in Fig. 2B,D. The circles with grey-, red-, and blue- color represents the first, second, and third layer, respectively, and the unit cell is marked as red dash square. In the double layered structure, shown in Fig. 2A, the unit cell length is about 720 nm, therefore the structure resembles FCC (100) face. The theoretical unit cell length (inter-particle distance in same plane) of FCC is about 707 nm, √2 times diameter of the particle. In the triple layered structure shown in Fig. 2C, the darkest spots represent the overlap of the first and third layer.

Bottom Line: Micro-domains of face-centered cubic (FCC (111)) and hexagonal close-packed (HCP (0001)) structures were dominantly found in PS-based PCs, while point and line defects, FCC (100), and 12-fold symmetry structures were also identified as minor components.Additionally, in situ observation capability for hydrated samples and 3D tomographic reconstruction of TXM images were also demonstrated.This soft X-ray full field TXM technique with faster image acquisition speed, in situ observation, and 3D tomography capability can be complementally used with the other X-ray microscopic techniques (i.e., scanning transmission X-ray microscopy, STXM) as well as conventional characterization methods (e.g., electron microscopic and optical/fluorescence microscopic techniques) for clearer structure identification of self-assembled PCs and better understanding of the relationship between their structures and resultant optical properties.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, College of Natural Sciences, Hanyang University, Seoul, 04763, Republic of Korea.

ABSTRACT
For the structural characterization of the polystyrene (PS)-based photonic crystals (PCs), fast and direct imaging capabilities of full field transmission X-ray microscopy (TXM) were demonstrated at soft X-ray energy. PS-based PCs were prepared on an O2-plasma treated Si3N4 window and their local structures and defects were investigated using this label-free TXM technique with an image acquisition speed of ~10 sec/frame and marginal radiation damage. Micro-domains of face-centered cubic (FCC (111)) and hexagonal close-packed (HCP (0001)) structures were dominantly found in PS-based PCs, while point and line defects, FCC (100), and 12-fold symmetry structures were also identified as minor components. Additionally, in situ observation capability for hydrated samples and 3D tomographic reconstruction of TXM images were also demonstrated. This soft X-ray full field TXM technique with faster image acquisition speed, in situ observation, and 3D tomography capability can be complementally used with the other X-ray microscopic techniques (i.e., scanning transmission X-ray microscopy, STXM) as well as conventional characterization methods (e.g., electron microscopic and optical/fluorescence microscopic techniques) for clearer structure identification of self-assembled PCs and better understanding of the relationship between their structures and resultant optical properties.

No MeSH data available.


Related in: MedlinePlus