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Organiczne ogniwa słoneczne

Graja A.

Postępy Fizyki

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2013

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T. 64, z. 1

2--11

PL

Opracowanie nowych, dogodnych metod syntezy materiałów fotoaktywnych i zastosowanie najnowszych rozwiązań technologicznych pozwala na wytwarzanie coraz efektywniejszych organicznych ogniw słonecznych. Niniejszy artykuł przeglądowy prezentuje istotne problemy organicznych ogniw słonecznych. Omówiono w nim m.in. krótka historie organicznych komórek słonecznych, podstawy fizyczne ich działania, budowę ogniw słonecznych, morfologię heterozłącz, najważniejsze materiały fotoaktywne i perspektywy energetyki solarnej. Celem tego artykułu jest tez pokazanie, jak znajomość struktury materiałów przyczynia się do lepszego zrozumienia działania ogniw i jak wiąże się ona z budowaniem efektywniejszych urządzeń przetwarzających światło w energie elektryczna.

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9. Międzynarodowe Sympozjum nt. Organicznych Metali, Nadprzewodników i Ferromagnetyków (ISCOM 2011), Poznań-Gniezno, 25-30 września 2011 roku

Graja A.

Postępy Fizyki

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2011

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T. 62, z. 6

282-283

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Optical study of ß”-(bis(ethylenedithio)tetrathiafulvalene)2SF5CH2SO3 Activation of intramolecular modes

Olejniczak I., Barszcz B., Graja A., Schlueter J. A.

Materials Science Poland

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2009

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Vol. 27, No. 3

621--627

EN

We report on the temperature dependences of polarized reflectance spectra of ß”-(bis(ethylenedithio) tetrathiafulvalene)2SF5CH2SO3. The material remains in the charge-ordered state over the whole temperature range. Room temperature infrared spectra display the response characteristic of a quasi-twodimensional organic conductor, with a broad mid-infrared electronic excitation and a number of vibrational features related to intramolecular modes of both the bis(ethylenedithio)tetrathiafulvalene (ET) donor molecule and the SF5CH2SO3 anion. Upon lowering the temperature, unusual activation of intramolecular modes of ET is observed. We suggest that this effect is connected with electronmolecular vibration coupling within a dimerized lattice.

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Kryształy Molekularne 2008

Graja A.

Postępy Fizyki

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2008

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T. 59, z. 5

223-224

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Spectral studies of (DB-TTF)(C3H2N3O3) salt-normal vibrations and intramolecular excitations

Barszcz B., Łapiński A., Graja A., Dutkiewicz G., Borowiak T., Flakina A. M., Lyubovskaya R. N.

Scientific Bulletin. Physics / Lodz University of Technology

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2006

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Vol. 26

47-53

EN

Charge transfer salt based on dibenzotetrathiafulvalene (DB-TTF) and the isocyanuric acid anion (C3H2N3O3)- was synthezided and characterized by spectral methods. The (DB-TTF)(C3H2N3O3) salt is a semiconductor with Eg=0.27 eV down to the 100K. The unit cell of (DB-TTF)(C3H2N3O3) salt is monoclinic, space group C2/m, a=23.865(11) Å, b=9.415(4) Å, c=3.701(3) Å, β=96.17(6)°, Z=2. Raman and absorption spectra of the investigated salt were analyzed using the density functional theory. On the base of these calculations an assignement of the vibrational and electronic features was proposed.

PL

Praca zawiera wyniki badań soli (DB-TTF)(C3H2N3O3) w tym dane dotyczące struktury krystalograficznej, przewodnictwa stałoprądowego oraz badań spektroskopowych (spektroskopia rozpraszania Ramana i spektroskopia absorpcyjna w zakresie od podczerwieni do ultafioletu). Widma eksperymentalne zinterpretowano w oparciu o wyniki obliczeń ab initio przeprowadzonych dla molekuły DB-TTF (neutralnej), kationu DB-TTF+ oraz anionu (C3H2N3O3)-. Ponadto przeprowadzono obliczenia wzbudzeń wewnątrzmolekularnych obydwu komponentów soli co pozwoliło na interpretację widm w zakresie UV-Vis-NIR. Analizując szczegółowo drgania normalne stwierdzono obecność dwóch typów molekuł donora w strukturze, ponadto dzięki badaniom przewodnictwa wykazano półprzewodnikowy charakter soli.

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Spectral studies of new organic conductors based on TTF derivatives with polymeric isocyanuric acid anions

Barszcz B., Łapiński A., Graja A., Flakina A. M., Lyubovskaya R. N.

Materials Science Poland

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2004

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Vol. 22, No. 4

339--346

EN

Spectral investigations of new organic conductors (BEDO-TTF)2(C3H2N3O3) and (DB-TTF) (C3H2N3O3) were performed. Optical absorption spectra in the range of 400-40 000 cm-1 of the powdered salts dispersed in KBr pellets were recorded and analysed. The spectra of (BEDO-TTF)2(C3H2N3O3) are characteristic of organic metals and show small anisotropy, which is typical of quasi-two-dimensional materials. On the other hand, the spectra of (DB-TTF)(C3H2N3O3) are typical of semiconducting materials. The (BEDO -TTF)2(C3H2N3O3) salt undergoes a phase transition at about 120 K. The polarized reflectance spectra of single crystals of (BEDO-TTF)2(C3H2N3O3) were recorded in the range of 600-7000 cm-1, down to 4 K. The frequency dependences of reflectivity were fitted with a Drude model and the transport parameters were evaluated and investigated vs. temperature. An assignment of some vibrational bands in the IR spectra was proposed.

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Optical properties of the one-dimensional organic conductors ß-(EDT-TTF-I2)2(Pb5/6 1/6I2)3 and ß-(EDT-TTF-I2)2(Pb2/3+xAg1/3-2x xI2)3, x = 0.05

Olejniczak I., Gromadziński B., Graja A., Devic T., Batail P.

Materials Science Poland

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2004

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Vol. 22, No. 4

347--352

EN

We report the room-temperature polarized infrared reflectance spectra of two radical cation salts based on halogenated TTF and two-dimensional polymeric iodoplumbate or Ag-doped iodoplumbate anions. These salts were ß-(EDT-TTF-I2)2(Pb5/6a1/6I2)3 and ß-(EDT-TTF-I2)2(Pb2/3+xAg1/3-2x??xI2)3, where x = 0.05 and a is a vacancy. Both materials display a metallic response, characteristic of quasi-onedimensional organic conductors. The ß-(EDT-TTF-I2)2(Pb2/3+xAg1/3-2x??xI2)3 salt, with x = 0.05 is partly transparent along the lowest conductivity direction in the infrared frequency range. The single-crystal polarized absorption spectrum recorded in this direction displays a number of vibrational features related to the intramolecular modes of the EDT-TTF-I2 molecule, which are assigned using available normal mode calculations. In addition, the absorption spectrum of the ß-(EDT-TTF-I2)2(Pb2/3+xAg1/3-2xaxI2)3 material dispersed in a KBr pellet is reported and discussed.

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Highly conducting organic composites obtained by charge transfer reaction in the solid state

Graja A., Golub M.

Materials Science Poland

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2004

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Vol. 22, No. 4

317--331

EN

In this paper, we shortly present and discuss structural, electrical and spectral properties of organic composites with the general formulae (BEDT-TTF)x/A and (BEDO-TTF)x/A, where A denotes an electron- acceptor species such as iodine, AuI, or AuI3. Electron transfer between large conducting grains restricts electrical conductivity of the composites; the most probable mechanism being fluctuation -induced tunneling conduction. Extensive spectral properties of organic composites are presented. It is shown that spectral studies can provide specific information about charge localization, electron-electron and electron-molecular vibration interactions, and about changes in the properties of highly conducting organic composites with ageing or annealing.

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New Bis-Linked Tetrathiafulvalenes (TTFs) to [60] Fullerene : Spectral Investigations

Olejniczak I., Graja A., Bogucki A., Gorgues A., Kreher D., Cariou M.

Polish Journal of Chemistry

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2002

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Vol. 76 / nr 1

95-102

EN

Extended spectral investigations of several new bis-linked tetrathiafulvalenes (TTFs) to [60]fullerene were performed. From VIS-NIR-IR spectra it was stated, that charge redistribution on C60 and TTFs moieties in the adducts occurs after their formation. This redistribution depends not only on the nature of a substituent but also on the number of bounded donors. Vibrational features of the polyadducts were also analyzed.

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Charge-Transfer in Fullerene Complexes

Graja A.

Polish Journal of Chemistry

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2002

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Vol. 76 / nr 2-3

167-176

EN

Spectral investigations of fullerene charge-transfer complexes with planar and spatial electron-donor molecules are reported. The results of this study indicate that the CT complexes of C60 with planar donors are involved in polarization interactions of van der Waals type. CT is very weak in these compounds and is hindered by unfavourable steric factors. As a result, the CT rate does not correlate with the ionization potential of the donor. Contrary to the planar donors, the spatial ones form complexes with CT rate approaching 1.

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Spectral studies of some C-60 complexes with TTF-derived donors

Graja A., Tanatar M.A., Li Y.L., Zhu D.B.

Polish Journal of Chemistry

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1998

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Vol. 72, nr 5

869-876

EN

Electronic and vibrational spectroscopies were applied to the study of the strength of the donor-acceptor interaction and optical properties of the complexes of C-60 with two TTF-derived donors, i.e. bis(methylthio)ethylenedithio-tetrathiafulvalene (C-1TET- TTF) and tetramethyltetraselenafulvalene (TMTSF). The investigations of the single crystalline samples, for various light polarizations and temperatures, were performed. The analysis of all the spectral data shows that the investigated compounds are weak complexes with a neutral ground state.