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β -Phase Morphology in Ordered Poly(9,9-dioctylfluorene) Nanopillars by Template Wetting Method

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ABSTRACT

An efficient method based in template wetting is applied for fabrication of ordered Poly(9,9-dioctylfluorene) (PFO) nanopillars with β-phase morphology. In this process, nanoporous alumina obtained by anodization process is used as template. PFO nanostructures are prepared under ambient conditions via infiltration of the polymeric solution into the pores of the alumina with an average pore diameter of 225 nm and a pore depth of 500 nm. The geometric features of the resulting structures are characterized with environmental scanning electron microscopy (ESEM), luminescence fluorimeter (PL) and micro μ-X-ray diffractometer (μ-XRD). The characterization demonstrates the β-phase of the PFO in the nanopillars fabricated. Furthermore, the PFO nanopillars are characterized by Raman spectroscopy to study the polymer conformation. These ordered nanostructures can be used in optoelectronic applications such as polymer light-emitting diodes, sensors and organic solar cells.

No MeSH data available.


Raman spectra of PFO film and nanopillars. The excitation laser is polarized parallel to the polymer chains and detection is polarized parallel (dashed line) and perpendicular (solid line).
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Figure 3: Raman spectra of PFO film and nanopillars. The excitation laser is polarized parallel to the polymer chains and detection is polarized parallel (dashed line) and perpendicular (solid line).

Mentions: Raman spectroscopy characterization is also performed in order to study the different polymer conformation into the nanoporous template. Raman studies can provide structural information on conjugated polymers, necessary for understanding of optical and electronic properties and the development of devices in which they are used as active layers. We have studied the effect on the Raman spectrum of the polymer chain orientation. The nanostructured samples were excited with the laser beam polarized parallel to the orientation direction of the pillars and the Raman signal measured polarized either parallel or perpendicular to the polymer backbones. Figure 3 shows the Raman spectra in the 1,000–1,700 cm-1 range for PFO film and PFO nanopillars. The most intense band is located at 1,604 cm-1 and is assigned to the phenyl intra-ring C–C stretch mode [4,24]. We observed that the intensity of the signal polarized parallel to the excitation is higher than that polarized perpendicular when the spectra is acquired for PFO nanopillars, but there are no changes in the intensity of the peaks when the sample is a PFO film. These Raman spectra indicate that the chains of the polymer are mainly parallel to the pillar in the nanostructure, but in the film, the chains are not aligned with respect to the laser beam. These results are in agreement with the PL measurements showed previously, where the emission spectrum is affected by the nanostructure.


β -Phase Morphology in Ordered Poly(9,9-dioctylfluorene) Nanopillars by Template Wetting Method
Raman spectra of PFO film and nanopillars. The excitation laser is polarized parallel to the polymer chains and detection is polarized parallel (dashed line) and perpendicular (solid line).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211439&req=5

Figure 3: Raman spectra of PFO film and nanopillars. The excitation laser is polarized parallel to the polymer chains and detection is polarized parallel (dashed line) and perpendicular (solid line).
Mentions: Raman spectroscopy characterization is also performed in order to study the different polymer conformation into the nanoporous template. Raman studies can provide structural information on conjugated polymers, necessary for understanding of optical and electronic properties and the development of devices in which they are used as active layers. We have studied the effect on the Raman spectrum of the polymer chain orientation. The nanostructured samples were excited with the laser beam polarized parallel to the orientation direction of the pillars and the Raman signal measured polarized either parallel or perpendicular to the polymer backbones. Figure 3 shows the Raman spectra in the 1,000–1,700 cm-1 range for PFO film and PFO nanopillars. The most intense band is located at 1,604 cm-1 and is assigned to the phenyl intra-ring C–C stretch mode [4,24]. We observed that the intensity of the signal polarized parallel to the excitation is higher than that polarized perpendicular when the spectra is acquired for PFO nanopillars, but there are no changes in the intensity of the peaks when the sample is a PFO film. These Raman spectra indicate that the chains of the polymer are mainly parallel to the pillar in the nanostructure, but in the film, the chains are not aligned with respect to the laser beam. These results are in agreement with the PL measurements showed previously, where the emission spectrum is affected by the nanostructure.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

An efficient method based in template wetting is applied for fabrication of ordered Poly(9,9-dioctylfluorene) (PFO) nanopillars with β-phase morphology. In this process, nanoporous alumina obtained by anodization process is used as template. PFO nanostructures are prepared under ambient conditions via infiltration of the polymeric solution into the pores of the alumina with an average pore diameter of 225 nm and a pore depth of 500 nm. The geometric features of the resulting structures are characterized with environmental scanning electron microscopy (ESEM), luminescence fluorimeter (PL) and micro μ-X-ray diffractometer (μ-XRD). The characterization demonstrates the β-phase of the PFO in the nanopillars fabricated. Furthermore, the PFO nanopillars are characterized by Raman spectroscopy to study the polymer conformation. These ordered nanostructures can be used in optoelectronic applications such as polymer light-emitting diodes, sensors and organic solar cells.

No MeSH data available.