Organic solar cells based on interpenetrated network of conjugated polymer as donor and fullerene derivative as acceptor materials have a great potential for improvement of the efficiency. We fabricated a device based on a composite of poly(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene (MEH-PPV) and [6,6]-phenyl C-60 butyric acid methyl ester (PCBM). Surface treatment, insertion of interfacial layers, and improvement of the morphology of the active layer significantly increase the photovoltaic performances of the structure. We obtained an open circuit voltage of 0.87 V and short circuit current density of -8.4 mA/cm(2) under 100 mW/cm(2) AM 1.5 solar simulator illumination, yielding a 2.9 % power conversion efficiency. Two others fullerene derivatives were synthesized in order to get a stronger acceptor. The electrical and optical properties of devices made with MEH-PPV and these acceptors are investigated.

[structure: see text] In four new dendrimers terminated by 12 electroactive tetrathiafulvalenyl substituents, the tridimensional character of the inter- and intradendrimeric charge and electron transfer, and hence of the electroconductivity, is evidenced by examination of the electronic spectra of their corresponding neutral state and cation radical, dication, and mixed-valence salts, including a closed-shell anion.

Organic solar cells based on an interpenetrated network of conjugated polymer as donor and fullerene derivative as acceptor materials have a great potential for improving efficiency. We fabricated a device based on a composite of poly(2-methoxy-5-(2′-ethylhexyloxy)-1, 4-phenylenevinylene and [6,6]-phenyl C60 butyric acid methyl ester. Surface treatment, insertion of interfacial layers, and improvement of the morphology of the active layer significantly increase the photovoltaic performances of the structure. We obtain an open circuit voltage of 0.87 V and short circuit current density of 8.4 mA/cm2 under 100 mW/cm2 air-mass 1.5 solar simulator illumination, yielding a 2.9% power conversion efficiency.

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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 C-60 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.

Extended spectral investigations of several new bis-linked tetrathiafulvalenes (TTFs) to [60]fullerene were performed. From UV–Vis–NIR–IR spectra, it was stated that charge distribution on the fullerene sphere and on the TTFs substituents is distinctly disturbed after the adduct formation. A particularly strong resonant effect was observed in the infrared spectra of the one of double-substituted fullerene molecules.

Our recent works on fused TTF–C60 dyads, (TTF)n–C60 polyads and C60–TTF–C60 dumbbell triads in which the acceptor C60 is doubly tethered to the donor tetrathiafulvalene through a rigidified cyclohexene ring are presented. This approach was developed in order to control the relative orientation as well as the distance between both donor and acceptor entities. Thereby, through-space interactions which are of great importance for photoinduced electron- and/or energy-transfer processes are expected to dominate because of the special topology of the molecules. The two linked C60 and TTF chromophores in such adducts are not only in close proximity but also have optimal orbital orientations, thus facilitating these through-space electronic interactions. These new C60-based assemblies were synthesized by [4 + 2] Diels–Alder cycloaddition reactions. The different methodologies considered for their synthesis are discussed, their analytical, spectroscopic characterizations and electrochemical properties are also described. The selective electro-oxidation or reduction afforded the corresponding radical cation and radical anion which were characterized by EPR. These C60-based assemblies were studied for their nonlinear optical and optical limiting applications. Moreover, intramolecular photoinduced charge-separation and charge-recombination processes in a fused C60–TTF–C60 dumbbell triad which was designed to be soluble in organic solvents were investigated by time-resolved absorption and fluorescence techniques. Appreciable interaction between the C60 moiety and TTF moiety in the ground state was suggested by steady-state absorption spectra and the fluorescence spectra showed considerable interaction in the singlet excited state. The nanosecond transient absorption spectra displayed the formation of the charge-separated radical pair C60–TTF˙+–C60˙−, characterized by a lifetime of ca. 20 ns in benzonitrile.

The title compounds, which are formed in very low yields by treating 2,3-bis(bromomethyl)tetrathiafulvalenes with naked iodide in the presence of C60, can be obtained in much higher yields by successive similar treatments of the major adducts produced at each step. The electrochemical properties of the unprecedented tri- and tetra-TTF/C60 assemblies are also presented.

Dumbbell C60–TTF–C60 was synthesized by a double cycloaddition of C60 with the unprecedented tetramethylidene[4H]TTF generated in situ from tetrakis(bromomethyl)TTF.

The synthesis and characterization of two classes of the title compounds are presented. In the first one, the tetrathiafulvalene (TTF) donor is linked to 1 or 2 C-60 through the cyclohexene spacer, and in the second one, oligothienylenevinylenes (OTV) donors of varied sizes are linked to 1 or 2 C-60 through a pyrrolidine ring.

The electrochemical process involved in electrospray ionization is used to obtain odd-electron molecular ions from C(60)-TTF-C(60) and its methano derivatives. Exact mass measurements obtained using high-resolution mass spectrometry are reported, and the gas-phase behavior of the radical cation (retro-Diels-Alder reaction and [M/2 + H](+) ion formation) is described.

The highly extended, cross-conjugated and sulfur rich π-electron donor 2a was synthesized and characterized introducing the 'H' shape as a new approach in the tetrathiafulvalene (TTF) array.

In this paper, we present an overview on the topics we are currently developing in our group. All of them deal with chemical modifications of the tetrathiafulvalene (TTF) framework aiming at reaching new organic materials endowed with specific electronic properties.

Monoadducts of tetrathiafulvalenc (TTF) with C60 are synthesized by [4+2] Diels-Alder cycloaddition using corresponding 2,3-bis(methylene)dihydroTTF 1. These cycloadducts 2 are spectroscopically characterized and electrochemically studied.

Efficient syntheses of novel 2,3-bis(bromomethyl)TTF derivatives 1 and tetrakis(bromomethyl)TTF 2, prone to generate corresponding 2,3-dimethylene[2H]-TTF 3 and tetramethylene[4H]-TTF 4 respectively, are reported.

In order to realize the bis-linking of tetrathiafulvalene (TTF) to one or two C60, and to reach the dyad compounds 1 and 2, the [4 + 2] Diels-Alder reactions of C60 with orthoquinodimethanic derivatives of 1,3-dithioles 5a,b or TTF 9 are studied.

A new and unexpected tetrathiafulvalene (TTF) core building process is observed via reaction of a 1,3-dithiole phosphonate anion with a 2-oxo-1,3-dithiole functionality.

The synthesis of new π-electron donors of tetrathiafulvalene family with hydroxy functionality is described through the reduction of ester group(s) in tetrakis(methoxycarbonyl)tetrathiafulvalene 1 and its vinylogous analogue 7 by using NaBH4 and LiCl in a mixed solvent of THF and CH2OH. These new π-donors have been studied electrochemically and spectroscopically.

The title reaction carried out from S-propargyl xanthate 3 or 2-(thi)oxo-4,5-bis(bromomethyl)-1,3-dithioles 4a and 4b with C60 is presented and some conversions of the synthesized cycloadducts 2a and 2b in several 1,3-dithiole derivatives are described.

The electrooxidation of 2,3-diarylbenzofurans leads to a rearrangement lactone, 3,3-diaryl-2(3H)-benzofuranone, together with a ring enlargement product, 9-aroyl-9-hydroxy-(9H)-xanthene. However, in some cases coupling products may be isolated in high yield.