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Organic & Hybrid Photonic Crystals
No full textPhotonic crystals (PhC) are composite systems where materials possessing different refractive index are arranged in a highly regular periodical structure having a length scale comparable to the wavelength of visible light[1]. The periodicity of the system can be extended over 1-, 2- or 3-dimensions.
The concept of PhC have been disclosed about twenty-five years ago by Yablonovitch[2] and John[3] with two seminal papers tackling fundamental issues like inhibition of spontaneous emission and light localization. Nowadays, PhCs find application in different fields spanning from photonics to photovoltaics and are gaining a great interest for sensing.[4-9] While the most widespread techniques used to growth photonic crystals are top-down ones, a great interest is currently devoted to fabrication of novel PhC structures with bottom-up methods or by processing from solution/melt. Moreover, their functionalization with suitable groups and/or with photoactive organic/hybrid materials in order to tailor their responsive properties for selected applications is intensively pursued.[4-5, 9-11]
In this communication, we will review the opportunities provided by organic PhC and we will focus on recent results obtained with 2D and 3D colloidal arrays (respectively, microsphere monolayers and opals) as well as on 1D all-polymer structures, which may add to photonic functionality unprecedented properties for their inorganic counterpart such as self-support (no need for a substrate) and mechanical flexibility.
1D all-polymer photonic crystals (i.e. Distributed Bragg Reflectors and microcavities) are grown by spin-coating by using polymer solutions in orthogonal solvents.[12-13] Even though, the technique is very simple, cheap and well known, limitations occurs when different constraints, such as high dielectric contrast, orthogonal solvents, control of the interfaces, transparency, lack of light scattering, have to be simultaneously considered. In spite of that, the technique allows to prepare free-standing and flexible DBR and microcavities, which can be successfully doped with photoactive materials (semiconducting, photochromic and clathrating polymers, J-aggregates) in order to obtain photonic platforms suitable for lasing, switching and sensing[12-14].
2D PhC, i.e. microsphere arrays can be prepared by floating[15]. Such systems have been successfully used as a template for grazing incident gold evaporation thus generating nanocrescents possessing different kind of anisotropic plasmonic resonances[15], which interact with photonic modes in opals. Moreover, microsphere monolayers show unusual second harmonic generation of circular dichroism[16].
Finally, artificial opals, the well-known playground for 3D photonic crystals have been used to show fluorescence enhancement effects and modulation of the radiative fluorescence lifetime. Three examples are described such as opals infiltrated with fluorescent solutions, opal infiltrated with conjugated polymers, and core-shell opals where the microspheres have been engineered in order to possess a shell doped with a fluorophore[17-18].
References
[1] J. D. Joannopulos; R. D. Meade; J. N. Win, Photonic Crystals: Molding the Flow of the Light. Princeton University Press: Princeton, 1995.
[2] E. Yablonovitch, Phys. Rev. Lett. 1987, 58.
[3] S. John, Phys. Rev. Lett. 1987, 58.
[4] J. Ge; Y. Yin, Angew. Chem. Int. Ed. 2011, 50, 1492.
[5] F. Li; D. P. Josephson; A. Stein, Angew. Chem. Int. Ed. 2011, 50, 360.
[6] T. Asano; S. Noda, Nature 2004, 429, 6988.
[7] D. Graham-Rowe, Nat Photon 2009, 3.
[8] M. F. Limonov; R. M. D. L. Rue, Optical Properties of Photonic Structures: Interplay of Order and Disorder. Taylor & Francis: 2012.
[9] J.-H. Lee; C. Y. Koh; J. P. Singer; S.-J. Jeon; M. Maldovan; O. Stein; E. L. Thomas, Adv. Mater. 2013, 26, 532.
[10] J. H. Moon; S. Yang, Chemical Reviews 2009, 110, 547.
[11] S. Furumi; H. Fudouzi; H. T. Miyazaki; Y. Sakka, Adv. Mater. 2007, 19.
[12] L. Frezza; M. Patrini; M. Liscidini; D. Comoretto, J. Phys. Chem. C 2011, 115, 19939.
[13] G. Canazza; F. Scotognella; G. Lanzani; S. D. Silvestri; M. Zavelani-Rossi; D. Comoretto, Laser Phys. Lett. in press (2014).
[14] S. Pirotta; M. Patrini; M. Liscidini; M. Galli; G. Dacarro; G. Canazza; G. Guizzetti; D. Comoretto; D. Bajoni, Appl. Phys. Lett. 2014, 104.
[15] V. Robbiano; M. Giordano; C. Martella; F. D. Stasio; D. Chiappe; F. B. d. Mongeot; D. Comoretto, Adv. Optical Mater. 2013, 1, 389.
[16] A. Belardini; A. Benedetti; M. Centini; G. Leahu; F. Mura; S. Sennato; C. Sibilia; V. Robbiano; M. C. Giordano; C. Martella; D. Comoretto; F. Buatier de Mongeot, Adv. Optical Mater. DOI: 10.1002/adom.201300385.
[17] L. Berti; M. Cucini; F. Di Stasio; D. Comoretto; M. Galli; F. Marabelli; N. Manfredi; C. Marinzi; A. Abbotto, J. Phys. Chem. C 2010, 114, 2403.
[18] F. Di Stasio; L. Berti; S. O. McDonnell; V. Robbiano; H. L. Anderson; D. Comoretto; F. Cacialli, APL Materials 2013, 1
IL PREMIO NOBEL PER LA CHIMICA 2000 AGLI SCOPRITORI DEI POLIMERI CONDUTTORI DI ELETTRICITA’
No full textOrganic and hybrid photonic crystals
No full textThe research field of Photonic Crystals, i.e., composite structures where materials
possessing different refractive index are assembled into a highly ordered dielectric
lattice with submicrometric periodicity, was founded in 1987 by the seminal papers
by E. Yablonovitch and S. John published in the same volume of Physical Review
Letters just 3 weeks one after the other. They provided the tools to rationalize the
dielectric lattices optics within a new formalism that not only is able to extend their
theoretical description but also becomes a source of inspiration for novel systems,
structures, and applications.
As it was already observed in other research fields, the development of novel
Photonic Crystals structures was based on the use of top-down approaches to
impart the dielectric structure into inorganic insulators and semiconductors. Such
techniques enable the fabrication of photonic structures possessing extraordinary
precision and finely tailored properties for selected technological applications.
Several books that have been so far published in the field of Photonic Crystals
are usually tuned to a specialist readership mainly composed of Physicists and
Engineers. Even though colloidal chemists and block copolymer scientists provided
important contributions to the field, a cultural and communication gap still exists
between fundamental Physics and Chemistry, as well as other disciplines of potential
interest to the Photonic Crystals field. For instance, novel organic and hybrid
materials that are revolutionizing the field of electronics and sensing can hardly be
nanostructured in the form of Photonic Crystals with top-down techniques. Furthermore,
biomedical applications could greatly benefit from the developments of
the field. In this respect, and in particular when organic and hybrid materials are
used, the use of the bottom-up approach as well as the exploitation of the chemistry
of the self-assembling process, widely exploited in Nature, provides an important
step forward to the field. This book, Organic and Hybrid Photonic Crystals, was
conceived as a bridge between different communities in order to establish a
common set of fundamental concepts and a language to be shared between Physicists,
Chemists, Biologists, Engineers, and Material Scientists.............
SUPRAMOLECULAR PROPERTIES OF POLYMERS FOR PLASTIC ELECTRONICS
No full textI INTRODUCTION
II FUNDAMENTAL PHYSICAL PROPERTIES
A Electronic Properties: chain orientation
B Photophysics: chain interaction
1 Polydiacetylene
2 Polyalkylthiophene
III PLASTIC ELECTRONICS: THE ROLE OF SUPRAMOLECULAR STRUCTURE
A Conducting and semiconducting polymers: transport properties
B Sensors
C Light Emitting Diodes
D Photovoltaic Cells
E Toward micro-devices
IV PERSPECTIVES & CONCLUSION
Organic and hybrid photonic crystals - Preface
No full textThis book provides a multidisciplinary perspective (ranging from chemistry to physics and biology) of the current research and applications of organic and hybrid photonic crystals. The authors detail the chemical and physical tools used to develop organic photonic crystals, explain methods for engineering new nano-structures, and propose novel physical phenomena or technological applications based on such materials. Organic and Hybrid Photonic Crystal lasers, sensors, photovoltaic devices and stimuli responsive devices are discussed
POLARIZED OPTICAL SPECTROSCOPY OF HIGHLY ORIENTED CONJUGATED POLYMERS: INTRA- AND INTER-MOLECULAR EFFECTS
No full text
Thin Polymer Films: Simple Optical Determination of Molecular Diffusion Coefficients
No full textThe possibility to assess diffusion coefficients of small molecules in packaging polymer films directly on the shelf, or even along the fabrication line, without the use laboratory equipment commonly employed for gravimetric methods would represent a paradigm changer in the evaluation of barrier properties and byproduct formation in goods packaging and device encapsulation. In this work, we demonstrate a simple, effective and versatile method for the determination of the molecular diffusion coefficients that exploits simple UV-Vis spectroscopy and is suitable for any polymer film. This simple method also allows the direct identification of the intercalating molecule without the need for chemical targeting or of complex laboratory equipment. For this purpose, we report on the assessment of diffusion coefficients of both polar and non-polar molecules including water, ammonia, methanol, ethanol, toluene, and even hexafluorobenzene into polyvinyl chloride wrap commercialized for food packagin
Label-free vapor selectivity by polymer-inorganic composite photonic crystals sensors
No full textThe lack of sensors for continuous and extensive detection of vapor pollutants is a concern for health and safety. Colorimetric sensors, such as polymer distributed Bragg reflectors, could achieve this task thanks to their low cost and easy signal transduction, but are affected by low vapor permeability and lack of selectivity without chemical labels. We demonstrate label-free selective sensing of organic volatile compounds by all-polymer Bragg reflectors relying on a high free volume hybrid inorganic-polymer nanocomposite to achieve vapor permeability, and on different intercalation kinetic of organic analytes to achieve selectivity
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