Search results for "Donor-acceptor"
showing 10 items of 14 documents
Role of the Open-Shell Character on the Pressure-Induced Conductivity of an Organic Donor-Acceptor Radical Dyad
2018
Single‐component conductors based on neutral organic radicals have received a lot of attention due to the possibility that the unpaired electron can serve as a charge carrier without the need of a previous doping process. Although most of these systems are based on delocalized planar radicals, we present here a nonplanar and spin localized radical based on a tetrathiafulvalene (TTF) moiety, linked to a perchlorotriphenylmethyl (PTM) radical by a conjugated bridge, which exhibits a semiconducting behavior upon application of high pressure. The synthesis, electronic properties, and crystal structure of this neutral radical TTF‐Ph‐PTM derivative (1) are reported and implications of its crystal…
Tuning of the photoinduced charge transfer process in donor-acceptor "double cable" copolymers
2003
The covalent linking of acceptor molecules to electron donating conjugated polymer is an approach for the development of new photoactive materials for the fabrication of organic photoelectric conversion devices. With this strategy we have designed a polyalkylthiophene copolymer series containing in the side chain anthraquinone molecules as electron acceptor. The peculiar features of the copolymers are the good processability and the ease in tailoring the content of acceptor moieties. Their potential use as photoactive materials is investigated in terms of the photoinduced charge transfer properties, studied by FTIR photoinduced absorption and Light Induced Electron Spin Resonance spectrosco…
A Straightforward Electroactive π-Extended Tetrathiafulvalene (exTTF) Building Block
2012
The synthesis and X-ray structure of a new and readily available exTTF derivative (6) bearing a methyltriphenylphosphonium bromide moiety as a new building block for the construction of electroactive molecules is reported. The phosphonium salt 6, which was prepared in one step from 2-hydroxymethyl-exTTF as a stable yellow solid in 84 % yield, efficiently undergoes Wittig olefination reactions with a variety of aldehydes to predominantly form the E isomer. Electronic spectra and cyclic voltammetry of the novel compounds reveal the electronic communication between the electroactive units.
Topological effects of a rigid chiral spacer on the electronic interactions in donor-acceptor ensembles
2005
Two triads (donor-spacer-acceptor), etTTF-BN-C 6 0 (6) and ZnP-BN-C 6 0 (7), in which electron donors (i.e., exTTF or ZnP) are covalently linked to C 6 0 through a chiral binaphthyl bridge (BN), have been prepared in a multistep synthetic procedure starting from a highly soluble enantiomerically pure binaphthyl building block (1). Unlike other oligomeric bridges, with hinaphthyl bridges, the conjugation between the donor and the acceptor units is broken and geometric conformational changes are facilitated. Consequently, distances and electronic interactions between the donor and C 6 0 are drastically changed. Both donor-spacer-acceptor (D-s-A) systems (i.e., 6 and 7) exhibit redox processes…
Ambipolar Phosphine Derivatives to Attain True Blue OLEDs with 6.5% EQE
2016
A family of new branched phosphine derivatives {Ph2N-(C6H4)n-}3P → E (E = O 1-3, n = 1-3; E = S 4-6, n = 1-3; E = Se 7-9, n = 1-3; E = AuC6F5 4-6, n = 1-3), which are the donor-acceptor type molecules, exhibit efficient deep blue room temperature fluorescence (λem = 403-483 nm in CH2Cl2 solution, λem = 400-469 nm in the solid state). Fine tuning the emission characteristics can be achieved varying the length of aromatic oligophenylene bridge -(C6H4)n-. The pyramidal geometry of central R3P → E fragment on the one hand disrupts π-conjugation between the branches to preserve blue luminescence and high triplet energy, while on the other hand provides amorphous materials to prevent excimer form…
Solid film versus solution-phase charge-recombination dynamics of exTTF-bridge-C60 dyads.
2005
The charge-recombination dynamics of two exTTF-C 6 0 dyads (exTTF=9,10-bis(l,3-dithiol-2-ylidene)-9,10-dihydroanthracene), observed after photoinduced charge separation, are compared in solution and in the solid state. The dyads differ only in the degree of conjugation of the bridge between the donor (exTTF) and the acceptor (C 6 0 ) moieties. In solution, photoexcitation of the nonconjugated dyad C 6 0 -BN-exTTF (1) (BN=1,1'-binaphthyl) shows slower charge-recombination dynamics compared with the conjugated dyad C 6 0 -TVB-exTTF (2) (TVB = bisthienylvinylenebenzene) (lifetimes of 24 and 0.6 μs, respectively), consistent with the expected stronger electronic coupling in the conjugated dyad.…
Luminescence properties of LiGaO2 crystal
2017
The study was supported by the Latvia-Lithuania-Taiwan research project “Nonpolar ZnO thin films: growth-related structural and optical properties” (Latvia: LV-LT-TW/2016/5 , Lithuania: TAP LLT 02/2014 , Taiwan: MOST 103-2923-M-110-001-MY3 ).
Probing molecular wire: synthesis of donor-acceptor ensembles exhibiting long range electron transfer
2005
A series of donor–acceptor arrays (C60–oligo-PPV–exTTF; 16–20) incorporating p-conjugated oligo(phenylenevinylene) wires (oligo-PPV) of different length between p-extended tetrathiafulvalene (exTTF) as electron donor and C60 as electron acceptor has been prepared by multistep convergent synthetic approaches. The electronic interactions between the three electroactive species present in 16–20 were investigated by UV-visible spectroscopy and cyclic voltammetry (CV). Our studies clearly show that, although the C60 units are connected to the exTTF donors through a p-conjugated oligo- PPV framework, no significant electronic interactions are observed in the ground state. Interestingly, photoindu…
Molecular wires - long range electron tunneling and hopping in novel donor-acceptor ensembles
2004
Selective Stepwise Suzuki Cross-Coupling Reaction for the Modelling of Photosynthetic Donor−Acceptor Systems
2009
A Suzuki reaction performed as a selective stepwise substitution of two boryl groups on a diarylporphyrin precursor is reported for straightforward construction of a porphyrin trimer, modeling photosynthetic donor-acceptor systems.