George A. Mousdis

Low temperature measurements of the electrical conductivities of some charge transfer salts with the asymmetric donors MDT-TTF, EDT-TTF and EDT-DSDTF. (MDT-TTF)2AuI2, a new superconductor (Tc=3.5 K at ambient pressure)

Abstract The electrical and x-ray structural properties of the new superconductor (MDT-TTF) 2 AuI 2 with a T c of 3.5 K at ambient pressure were studied (MDT-TTF = methylenedithio-tetrathiafulvalene). Low temperature measurements of the electrical conductivities of two new metals, (EDT-TTF) 2 IBr 2 and (EDT-DSDTF) 2 AuI 2 are reported (EDT-TTF = ethylenedithio-tetrathiafulvalene, EDT-DSDTF = ethylenedithio-diselenadithiafulvalene).

Some new organic–inorganic hybrid semiconductors based on metal halide units: structural, optical and related properties†

The structural, optical and related properties of organic–inorganic hybrid semiconductors based on the organic molecules (cations) CH3NH3, H3N(CH2)6NH3, C6H5CH2NH3, CH3C6H4CH2NH3, CH3OC6H4CH2CH2NH3, (H2N)2CS(CH2)4SC(NH2)2, H3NCH2CH2OCH2CH2NH3, C6H5CH2CH2SC(NH2)2, C10H21SC(NH2)2, O2NC6H4CH2SC(NH2)2, 1-naphthylmethylammonium C10H7CH2NH3, 9-anthrylmethylammonium C14H9CH2NH3 and 1-pyrenylmethylammonium C16H9CH2NH3 and the inorganic units MXn (anions) (M≡Bi, Sb, Sn, Pb, Cu, Ag; X≡I, Br, Cl) are described. There is evidence that the position, intensity and shape of the excitonic bands depend on the order/disorder of the inorganic component and on the electronic interaction between organic and inorganic components. Copyright

Preparation and characterization of [H3N(CH2)6NH3]PbI4 and similar compounds with a layered perovskite structure

The preparation, crystal structure and optical absorption spectra of [H3N(CH2)6NH3]PbX4 (X = I, Br, Cl) and similar compounds based on Sn are described. The compounds [H3N(CH2)6NH3]PbX4 consist of ordered perovskite sheets of the corresponding-corner sharing PbX6 octahedra, which alternate with the H3N(CH2)6NH3 sheets. The excitonic peaks in the optical absorption spectra of these compounds occur at shorter wavelengths than those of the corresponding compounds with the formula [C6H5CH2CH2NH3]2MX4.

Bis (Alkylthio) Tetrathiafulvalenes and a Few of Their Salts

Abstract Some unsymmetrical bis(alkylthio) tetrathiafulvalenes (π-donors) and a number of their charge transfer complexes and cation radical salts of the type DmXn (where D=π-donor, X=TCNQ, I3, IBr2, PF6, CIO4) have been prepared and studied.

Nanocrystalline/microcrystalline materials based on lead-halide units

The preparation, photoluminescence (PL) spectra and related properties of particulate (nanocrystalline/microcrystalline) materials based on Pb(BrxCl1−x)3, Pb(BrxI1−x)3, and Pb(ClxI1−x)3 (x = 0–1) units, in several macroscopic forms, are reported. The materials in the form of suspensions in toluene or in toluene containing polymethyl methacrylate (PMMA) were obtained from the corresponding n-layer materials (or their precursors), mainly, by a titration-like method. This is the injection of solutions of the corresponding compounds with the Pbn(BrxCl1−x)3n+1, Pbn(BrxI1−x)3n+1, and Pbn(ClxI1−x)3n+1 (n > 2) units, respectively, into neat toluene or toluene–PMMA, with parallel observation of the PL-spectra. With this method, the mass of the lead-halide materials is controlled and the position of the low frequency PL band could be tuned in a wide spectral range, i.e., from ca. 400 to ca. 700 nm. From the suspensions in toluene the corresponding materials in the form of precipitates (powders) were obtained by centrifugation and decantation. From suspensions in toluene–PMMA, the corresponding materials in the form of composite thin films (of PMMA-matrix) were obtained by drop-casting, deep-coating and/or spin-coating techniques. So, blue, green, yellow and red narrow PL-band (of 20–35 nm) emitters (in forms of suspensions, powders and films) were obtained and their PL and optical absorption spectra were investigated further. The PL-intensity varies as in the case of CsPbBr3 particles in a CsBr matrix. Also, some similarities with the spectra of metal chalcogenide quantum dots were found. They were suggested as candidate materials for several optical and optoelectronic applications.

Transition-Metal 1,2 Diheterolenes and Polyheterotetra-heterafulvalenes: Precursors of Conducting Solids

Abstract Methods for synthesis and properties of oxygen-, sulfur-, selenium-, and nitrogen-containing transition-metal 1,2-diheterolenes and polyheterotetrahetera-fulvalenes are described. Also, the preparation and properties of some conducting salts based on these compounds are briefly discussed.

Conducting solids based on some new unsymmetrical tetraheterofulvalenes

Abstract Some new unsymmetrical polysulfur- or pyrazino-tetraheterofulvalenes (D) and a number of their charge transfer complexes and cation radical salts of the type D n X [where D=donor, X=TCNQ, Ni(dmit) 2 , Ni(dcit) 2 , I 3 , AuI 2 , IBr 2 , SCN, C10 4 , and PF 6 ] were prepared and studied. Most of the D n X were found to be conducting solids.

Preparation, structure and optical properties of [CH3SC(NH2)NH2]3PbI5, [CH3SC(NH2)NH2]4Pb2Br8and [CH3SC(NH2)NH2]3PbCl5·CH3SC(NH2)NH2Cl

The preparation, crystal structures and optical absorption spectra of [CH3SC(NH2)NH2 ]3PbI51, [CH3SC(NH2)NH2 ]4Pb2Br82 and [CH3SC(NH2)NH2 ]3PbCl5·CH3SC(NH2)NH2Cl 3 are reported. Compounds 1 and 3 consist of deformed PbX6 octahedra, which share opposite corners to form quasi-zero-dimensional or one-dimensional infinite chains along the a-axis. Compound 2 consists of Pb2Br9 units which are connected with two neighbouring units by non-opposite Br atoms; in this way, infinite zigzag chains are formed. A blue shift of the excitonic absorption bands, in comparison to those of systems with higher dimensionality, is observed.

Notizen: Preparation, Structures and Optical Properties of [H3N(CH2)6NH3]BiX5 (X=I, Cl) and [H3N(CH2)6NH3]SbX5 (X=I, Br)

Abstract The preparation, crystal structures and optical absorption spectra of [H3N(CH2)6NH3]BiX5 (X= I, Cl) and [H3N(CH2)6NH3]SbX5 (X =I, Br) are reported. The anions of the compounds consist of MX6-octahedra (M =Bi, Sb) sharing cisvertices in one-dimensional zig-zag chains. Because of their one-dimensional character, a blue shift of the excitonic absorption bands, in com parison to those of higher dim ensionality systems (MX3), is observed.

Preparation and Characterization of [C6H5CH2 NH3]2PbI4, [C6H5CH2CH2SC(NH2)2]3 PbI5 and [C10H7CH2NH3]PbI3 Organic-Inorganic Hybrid Compounds

The preparation, crystal structures, optical absorption spectra, and photoluminescence spectra of the title compounds are reported. The compounds were prepared in single crystal form. [C6H5CH2NH3]2PbI4 consists of anionic perovskite sheets of corner-sharing Pbl6 octahedra, which alternate with the C6H5CH2NH3+ sheets. [ C6H5CH2CH2SC(NH2)2]3 PbI5 consists of zig-zag chains of anionic corner sharing PbI6 octahedra separated by C6H5CH2CH2SC(NH2)2 cations. [C10H7CH2NH3]Pbl3 consists of twin chains of edge-sharing PbI6 octahedra separated by C10H7CH2NH3 cations. The compounds are thus low-dimensional systems. The excitonic spectra were observed in all cases, even at room temperature, and the possibility of organicinorganic excitonic interactions is discussed.