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|About Us||Macroscopic Quantum Phenomena
in 3D-ordered conjugated systems
|Discovery of nanopolyacetylene|
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|Custom Synthesis||Invitation to cooperation||Properties of nanopolyacetylene|
|Custom Research & Development||Introduction to Project||Current studies|
|Contact us||Executive Summary||Self-organization of nanopolyacetylene|
|Raman Labels||Nonadiabatic Raman scattering||Hyper-sensors||Invers-Peierls transition in quasi-1-D|
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Crbon nanotubes (2001 - 2005)
It was found that single-wolled carbon nanotubes (SWNT) (1), bipolar molecules (2) and polar saturated polymers (3) form ternary complexes (1-2-3), which are soluble
in organic solvents and polymeric solutions. Reaction of complexation is very sensitive to diameter, chirality and electronic stsucture of carbon nanotubes. Thus, it can be used for preparation SWNT with identical chirality.
Raman spectroscopy analysis show that purity and quality of SWNT in soluble gels and composites is much higher than in initial suspensions.
Optical properties of nanopolyacetylene at laser excitation (Abstract 2004)
Polyacetylene (PA) is one of the most promising materials for applications in optoelectronics. The major obstacle on the way of practical applications of PA is its low stability, which is caused by high sensitivity of polyene chain to defects. This report is dedicated to the new modification of PA - nanopolyacetylene (NPA), which is obtained by polymerization of acetylene at Re catalyst in solution of poly (vinyl butyral) (PVB). Composites of NPA-PVB are highly stable. They can be prepared in forms of solutions, films and plates. They exhibit set of unique optical properties, which are not characteristic of the standard PA modifications.
NPA is characterized by: 1) vibrational structure of cis- and trans- bands in optical absorption spectra; 2) absence of charged soliton peak in photoinduced optical absorption spectra; 3) transparency window in the near-IR region; 4) extremely low intensity of fluorescence at excitation in visual region; 5) high intensity of resonant and non-resonant Raman scattering on fundamentals of polyene chain.
Optical properties of free-standing NPA-PVB films subjected to laser irradiation are especially interesting. They are characterized by extremely high intensity of Stokes Raman scattering, extremely low intensity of anti-Stokes Raman scattering and extremely high stability under resonant and non-resonant laser irradiation. For instance, excitation of Raman scattering for free-standing NPA film with thickness = 1 mm and optical density in near IR field = 1, by 1064 nm continuous wave laser with beam energy = 3000 Wt/cm2 does not lead to film distraction. Ratios I anti-Stokes / I Stokes of fundamentals of polyene chain for laser beam energy = 300 Wt/cm2 is very low (see below). The temperature evaluation including optical density ratio at vawelengths of Stokes and anti-Stokes scattered photons corresponds to the temperature of 80 K.
These results allow one to suppose that 1064 nm continuous wave laser irradiation of free-standing NPA-PVB film leads to excitation of coherent phonons and energy exchange between nanoparticles, which are irradiated with those that are not irradiated.
Scattering of X-ray beam on coherent phonons of nanopolyacetylene (2003)
It is shown that scattering of X-ray beam on coherent
phonons of NPA modulate X-ray beam. Thus, NPA can be
used for elaboration of X-ray switch.
Introduction to application
NPA is the first sinthetic organic material, which possess coherent optical properties under continuous wave laser irradiation. Generation of coherent phonons under impulsive laser irradiation was demonstrated earlier for some inorganic semiconductors. As a rule frequencies of coherent phonon modes in inorganic semiconductors is 5 to 20 times lower than frequencies of coherent phonon modes in conjugated polymers. Thus, the coherent states of NPA should be much more stable to fluctuations of energy than the one of inorganic semicondactors. Below you can see Raman scattering spectrum of composite of 1% NPA in matrix of poly (vinyl butyral) for excitation 785 nm diode laser with power 10 mW and exposure 0.075 sec. Calculated ratio signal to noise with these conditions is 64 dB.
Composites of NPA can be used for elaboration:
1. Different types of switches and sensors;
Invitation to cooperation
We look forward to establishing cooperation with research & development laboratories, institutions, and companies in study:
1) specific Heat of NPA;
2) impulsive stimulated Raman scattering of NPA;
3) magneto-optical properties of NPA at laser excitation;
4) generation of coherent optical and acoustic phonons;
5) generation of THz radiation at impulsive and continuous laser irradiation;
6) scattering of X-ray beam on coherent optical phonons;
Please don't hesitate to contact us for further information.