Search results for "Donor-acceptor"
showing 4 items of 14 documents
Donor-Acceptor Polythiophene Copolymers with Tunable Acceptor content for Photoelectric Conversion Devices
2004
The synthesis and characterization of a new series of substituted polythiophenes containing an electron acceptor anthraquinone moiety in the side chain are reported. The acceptor molar content was varied by the co-polymerization of both alkylthiophene and thiophene bearing anthraquinone monomers in different ratios. NMR analysis shows a good correlation between the monomer feed composition at the beginning of the polymerization and the actual unit composition of the backbone. The conjugation length and the chemical composition of the copolymers as a function of the molecular weight have been studied by size exclusion chromatography. Small angle X-ray scattering and UV-Vis absorption spectra…
Comparison of Luminescence in LiGaO2, Al2 O3 -Ga and Al2 O3 -Li Crystals
2018
We have studied luminescence of LiGaO 2 , Al 2 O 3 -Ga and Al 2 O 3 -Li crystals in order to reveal the nature of luminescence centres and mechanisms in these crystals. In Al 2 O 3 -Ga presence of Ga impurities determines occurrence of the 280 nm emission band, which demonstrates intra-centre character in photoluminescence and recombination character under X-ray irradiation. In Al 2 O 3 -Li crystal lithium induced luminescence is presented with the 326 nm band, which has a recombination character. Basing on spectral similarity of the main luminescence bands in pure LiGaO 2 crystal with the dopant-induced emission bands in Al 2 O 3 , and on peculiarities of the X-ray induced thermoluminescen…
Solvatochromic behaviour of new donor–acceptor oligothiophenes
2021
Oligothiophene derivatives play a central role in the formulation of materials used in devices in the field of organic electronics. In this work, we report the results of the study of UV-vis absorption and fluorescence spectra, in several solvents, of a series of oligothiophenes recently synthesized in our laboratory. The studied oligothiophenes present different structures due to several factors: the donor– acceptor (D–A) or acceptor–donor–acceptor (A–D–A) architecture, the number of thiophene rings in the backbone (ranging from three to eight), the number and position of solubilizing octyl chains in the backbone, and the type of acceptor moieties (from Knoevenagel condensation either with…
Low‐Valent Germanylidene Anions: Efficient Single‐Site Nucleophiles for Activation of Small Molecules
2021
Abstract Rare mononuclear and helical chain low‐valent germanylidene anions supported by cyclic (alkyl)(amino)carbene and hypermetallyl ligands were synthesised by stepwise reduction from corresponding germylene precursors via stable and isolable germanium radicals. The electronic structures of the anions can be described with ylidene and ylidone resonance forms with the Ge−C π‐electrons capable of binding even weak electrophiles. The germanylidene anions reacted with CO2 to give μ‐CO2‐κC:κO complexes, a rare coordination mode for low‐valent germanium and inaccessible for the related neutral germylones. These results implicate low‐valent germanylidene anions as efficient single‐site nucleop…