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Dip-pen patterning of poly(9,9-dioctylfluorene) chain-conformation-based nano-photonic elements.

Perevedentsev A, Sonnefraud Y, Belton CR, Sharma S, Cass AE, Maier SA, Kim JS, Stavrinou PN, Bradley DD - Nat Commun (2015)

Bottom Line: Here we show that a metamaterials approach, using a discrete physical geometry (conformation) of the segments of a polymer chain as the vector for a substantial refractive index change, can be used to enable visible wavelength, conjugated polymer photonic elements.In particular, we demonstrate that a novel form of dip-pen nanolithography provides an effective means to pattern the so-called β-phase conformation in poly(9,9-dioctylfluorene) thin films.This can be done on length scales ≤500 nm, as required to fabricate a variety of such elements, two of which are theoretically modelled using complex photonic dispersion calculations.

View Article: PubMed Central - PubMed

Affiliation: 1] Department of Physics and Centre for Plastic Electronics, Imperial College London, London SW7 2BZ, UK [2] Department of Physics, Imperial College London, London SW7 2BZ, UK.

ABSTRACT
Metamaterials are a promising new class of materials, in which sub-wavelength physical structures, rather than variations in chemical composition, can be used to modify the nature of their interaction with electromagnetic radiation. Here we show that a metamaterials approach, using a discrete physical geometry (conformation) of the segments of a polymer chain as the vector for a substantial refractive index change, can be used to enable visible wavelength, conjugated polymer photonic elements. In particular, we demonstrate that a novel form of dip-pen nanolithography provides an effective means to pattern the so-called β-phase conformation in poly(9,9-dioctylfluorene) thin films. This can be done on length scales ≤500 nm, as required to fabricate a variety of such elements, two of which are theoretically modelled using complex photonic dispersion calculations.

No MeSH data available.


A thin-film chain-conformation-based photonic grating structure.Full, complex dispersion calculations for the TE- and TM-guided modes are shown for a 150-nm-thick film, periodically patterned with alternating stripes of β- and glassy-phase PFO. A period of Λ=290 nm was selected with the β- and glassy-phase regions spanning, respectively, 75% and 25%. In (a), the modal dispersion, displayed in a reduced zone scheme, highlights the distinct band gaps (horizontal grey bars) for both TE (blue) and TM (red) modes. Propagation losses for both modes are shown in (b) along with the absorption in the β-phase region (dotted line). The unit cell of the photonic structure is shown in (c), with the upper and lower red horizontal lines indicating film interfaces with air and the substrate, respectively. The vertical solid black line delineates the centre of a single period and the vertical dashed lines delineate the edges of the β-phase stripe. The stripe long axis runs into the page, in the y-direction. The illustrative calculated field distributions (/Hy(x,z)/2) at 454.5 and 458 nm (darker=larger modulus) clearly reveal the characteristic standing wave patterns (and their spatial displacement) for wavelengths selected to lie on either side of the TM band gap.
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f5: A thin-film chain-conformation-based photonic grating structure.Full, complex dispersion calculations for the TE- and TM-guided modes are shown for a 150-nm-thick film, periodically patterned with alternating stripes of β- and glassy-phase PFO. A period of Λ=290 nm was selected with the β- and glassy-phase regions spanning, respectively, 75% and 25%. In (a), the modal dispersion, displayed in a reduced zone scheme, highlights the distinct band gaps (horizontal grey bars) for both TE (blue) and TM (red) modes. Propagation losses for both modes are shown in (b) along with the absorption in the β-phase region (dotted line). The unit cell of the photonic structure is shown in (c), with the upper and lower red horizontal lines indicating film interfaces with air and the substrate, respectively. The vertical solid black line delineates the centre of a single period and the vertical dashed lines delineate the edges of the β-phase stripe. The stripe long axis runs into the page, in the y-direction. The illustrative calculated field distributions (/Hy(x,z)/2) at 454.5 and 458 nm (darker=larger modulus) clearly reveal the characteristic standing wave patterns (and their spatial displacement) for wavelengths selected to lie on either side of the TM band gap.

Mentions: A pertinent question is to what degree the refractive index contrast between β-phase structured and baseline glassy PFO is of practical interest in this context. Our analysis, based on modelling, suggests that it can readily satisfy typical requirements. As an example, the full (complex) photonic dispersion for transverse electric (TE) and transverse magnetic (TM) modes propagating in a 150-nm thickness PFO film with periodically patterned β-phase stripes (Λ=290 nm, 75% fill factor, β-phase fraction as for the decalin-immersed reference film shown in Fig. 1) is displayed in Fig. 5.


Dip-pen patterning of poly(9,9-dioctylfluorene) chain-conformation-based nano-photonic elements.

Perevedentsev A, Sonnefraud Y, Belton CR, Sharma S, Cass AE, Maier SA, Kim JS, Stavrinou PN, Bradley DD - Nat Commun (2015)

A thin-film chain-conformation-based photonic grating structure.Full, complex dispersion calculations for the TE- and TM-guided modes are shown for a 150-nm-thick film, periodically patterned with alternating stripes of β- and glassy-phase PFO. A period of Λ=290 nm was selected with the β- and glassy-phase regions spanning, respectively, 75% and 25%. In (a), the modal dispersion, displayed in a reduced zone scheme, highlights the distinct band gaps (horizontal grey bars) for both TE (blue) and TM (red) modes. Propagation losses for both modes are shown in (b) along with the absorption in the β-phase region (dotted line). The unit cell of the photonic structure is shown in (c), with the upper and lower red horizontal lines indicating film interfaces with air and the substrate, respectively. The vertical solid black line delineates the centre of a single period and the vertical dashed lines delineate the edges of the β-phase stripe. The stripe long axis runs into the page, in the y-direction. The illustrative calculated field distributions (/Hy(x,z)/2) at 454.5 and 458 nm (darker=larger modulus) clearly reveal the characteristic standing wave patterns (and their spatial displacement) for wavelengths selected to lie on either side of the TM band gap.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4309429&req=5

f5: A thin-film chain-conformation-based photonic grating structure.Full, complex dispersion calculations for the TE- and TM-guided modes are shown for a 150-nm-thick film, periodically patterned with alternating stripes of β- and glassy-phase PFO. A period of Λ=290 nm was selected with the β- and glassy-phase regions spanning, respectively, 75% and 25%. In (a), the modal dispersion, displayed in a reduced zone scheme, highlights the distinct band gaps (horizontal grey bars) for both TE (blue) and TM (red) modes. Propagation losses for both modes are shown in (b) along with the absorption in the β-phase region (dotted line). The unit cell of the photonic structure is shown in (c), with the upper and lower red horizontal lines indicating film interfaces with air and the substrate, respectively. The vertical solid black line delineates the centre of a single period and the vertical dashed lines delineate the edges of the β-phase stripe. The stripe long axis runs into the page, in the y-direction. The illustrative calculated field distributions (/Hy(x,z)/2) at 454.5 and 458 nm (darker=larger modulus) clearly reveal the characteristic standing wave patterns (and their spatial displacement) for wavelengths selected to lie on either side of the TM band gap.
Mentions: A pertinent question is to what degree the refractive index contrast between β-phase structured and baseline glassy PFO is of practical interest in this context. Our analysis, based on modelling, suggests that it can readily satisfy typical requirements. As an example, the full (complex) photonic dispersion for transverse electric (TE) and transverse magnetic (TM) modes propagating in a 150-nm thickness PFO film with periodically patterned β-phase stripes (Λ=290 nm, 75% fill factor, β-phase fraction as for the decalin-immersed reference film shown in Fig. 1) is displayed in Fig. 5.

Bottom Line: Here we show that a metamaterials approach, using a discrete physical geometry (conformation) of the segments of a polymer chain as the vector for a substantial refractive index change, can be used to enable visible wavelength, conjugated polymer photonic elements.In particular, we demonstrate that a novel form of dip-pen nanolithography provides an effective means to pattern the so-called β-phase conformation in poly(9,9-dioctylfluorene) thin films.This can be done on length scales ≤500 nm, as required to fabricate a variety of such elements, two of which are theoretically modelled using complex photonic dispersion calculations.

View Article: PubMed Central - PubMed

Affiliation: 1] Department of Physics and Centre for Plastic Electronics, Imperial College London, London SW7 2BZ, UK [2] Department of Physics, Imperial College London, London SW7 2BZ, UK.

ABSTRACT
Metamaterials are a promising new class of materials, in which sub-wavelength physical structures, rather than variations in chemical composition, can be used to modify the nature of their interaction with electromagnetic radiation. Here we show that a metamaterials approach, using a discrete physical geometry (conformation) of the segments of a polymer chain as the vector for a substantial refractive index change, can be used to enable visible wavelength, conjugated polymer photonic elements. In particular, we demonstrate that a novel form of dip-pen nanolithography provides an effective means to pattern the so-called β-phase conformation in poly(9,9-dioctylfluorene) thin films. This can be done on length scales ≤500 nm, as required to fabricate a variety of such elements, two of which are theoretically modelled using complex photonic dispersion calculations.

No MeSH data available.