Controlling Interfacial Charge Transfer and Fill Factors in CuO‐based Tandem Dye‐Sensitized Solar Cells

We designed and synthesized a series of novel electron‐accepting zinc(II)phthalocyanines (ZnPc) and probed them in p‐type dye sensitized solar cells (p‐DSSCs) by using CuO as photocathodes. By realizing the right balance between interfacial charge separation and charge recombination, optimized fill factors (FFs) of 0.43 were obtained. With a control over fill factors in p‐DSSCs in hand we turned our attemtion to t‐DSSCs, in which we combined for the first time CuO‐based p‐DSSCs with TiO₂‐based n‐DSSCs using ZnPc and N719. In the resulting t‐DSSCs, the V_OC of 0.86 V is the sum of those found in p‐ and n‐DSSCs, while the FF remains around 0.63. It is only the smaller J_scs in t‐DSSCs that limits the efficiency to 0.69 %.     

Synthese und Kristallstruktur von Blei(II)‐oxidhalogenid‐Alkoholaten mit unterschiedlichen Verknüpfungsvarianten von Pb4O4‐Heterokubaneinheiten

Synthesis and Crystal Structure Determination of Lead(II) Oxide Halide Alcoholates with Different Connectivity of Pb₄O₄ Heterocubane‐like Subunits The reaction of red lead(II) oxide (Litharge) and lead(II) halide (Cl^? and Br^?) with diethylene glycole at a temperature of 180 °C leads to the isotypic compounds [Pb₆(C₄H₈O₃)O₂Cl₆] (1) and [Pb₆(C₄H₈O₃)O₂Br₆] (2) . In a similar synthesis with PbI₂ as educt at temperature of 160 °C the two modifications β‐[Pb₆(C₄H₈O₃)O₂I₆] (3) and α‐[Pb₆(C₄H₈O₃)O₂I₆] (4) were found, whereas at a reaction temperature of 180 °C [Pb₉(C₂H₄O₂)(C₄H₈O₃)O₃I₈] (5) was surprisingly obtained as product. The X‐ray diffraction data show that at a temperature of 180 °C a splitting of the ether took place. The cited compounds show cubane like subunits built by lead and oxygen atoms. These fragments are connected by alkoholate molecules. In 5 additionally an I₆ octahedra centered by lead is observed.     

Präparation,Kristallstruktur, Schwingungsspektren und thermische Analyse von Kupfer‐tetrahydrogen‐decaoxo‐diperiodat‐hexahydrat CuH4I2O10·6H2O

On Copper‐tetrahydrogen‐decaoxo‐diperiodate‐hexahydrate CuH₄I₂O₁₀·6H₂O: Crystal Structure, Vibrational Spectroscopy and Thermal Analysis By crystallization from a strongly acidic aqueous solution copper‐tetrahydrogen‐decaoxodiperiodate‐hexahydrate CuH₄I₂O₁₀· 6H₂O has been obtained. In the structure of this compound (S.G. P 2₁/c, Nr.14), Z = 2, a = 1060.2(2) pm, b = 551.1(1) pm, c = 1164.7(2) pm, β = 111, 49(3)°) centrosymmetric [H₄I₂O₁₀]^2— anions in the form of two edge sharing octahedra form layers via hydrogen bonds originating from the acidic, trans‐configurated OH groups of the anions. Raman spectra are given and analyzed with respect to the internal vibrations of the periodate anion. The dehydration of the compound takes place via CuH₄I₂O₁₀·3H₂O and Cu(H₂IO₅)₂ which decomposes at 170 °C to Cu(IO₃)₂.     

Kristallstrukturen und spektroskopische Untersuchungen ternärer CuII-Komplexe mit bicyclischen Dicarbonsäuren und N,N-Donor-Liganden

Crystal Structures and Spectroscopic Investigations of Ternary Cu^II-Complexes with Bicyclic Dicarboxylic Acids and N,N-Donor Ligands The synthesis of coordination compounds [CuLdam] · 3H₂O (H₂L = 7-oxa-bicyclo[2.2.1]heptane-2-exo,3-cis-dicarboxylic acid ( 1 ) and its 1-methyl-derivative ( 2 ); dam = ethylendiamine, 1,2- and 1,3-propylendiamine, 2,2′-dipyridyl, 1,10-phenanthroline) has been described. Results of visible and IR spectroscopy and magnetic data are given. In the result of X-ray analyses of [CuL¹dipy] · 3H₂O ( 1 d ) and [CuL²en] · 3H₂O ( 2 a ) the dicarboxylate anions of 1 and 2 proved to be tridentate chelating ligands. In 1 d the Cu atom has an approximately square-pyramidal coordination with the bridging O atom in the apical position. In 2 a , however, the coordination number is extended to six by an O atom of a second [CuL²en] unit resulting in a centrosymmetric complex dimer with octahedrally coordinated Cu atoms. The water molecules do not participate in the coordination of the Cu atoms and form a complicated system of hydrogen bonds in the crystal.     

Synthese,Struktur und EPR‐Untersuchungen von binuklearen Bis(N,N,N‴,N‴‐tetraisobutyl‐N′,N″‐isophthaloylbis(thioureato))‐Komplexen des CuII,NiII, ZnII,CdII und PdII

Synthesis, Structure and EPR Investigations of binuclear Bis(N,N,N?,N?‐tetraisobutyl‐N′,N″‐isophthaloylbis(thioureato)) Complexes of Cu^II, Ni^II, Zn^II, Cd^II and Pd^II The synthesis of binuclear Cu^II‐, Ni^II‐, Zn^II‐, Cd^II‐ and Pd^II‐complexes of the quadridentate ligand N,N,N?,N?‐tetraisobutyl‐N′,N″‐isophthaloylbis(thiourea) and the crystal structures of the Cu^II‐ and Ni^II‐complexes are reported. The Cu^II‐complex crystallizes in two polymorphic modifications: triclinic, (Z = 1) and monoclinic, P2₁/c (Z = 2). The Ni^II‐complex was found to be isostructural with the triclinic modification of the copper complex. The also prepared Pd^II‐, Zn^II‐ and Cd^II‐complexes could not be characterized by X‐ray analysis. However, EPR studies of diamagnetically diluted Cu^II/Pd^II‐ and Cu^II/Zn^II‐powders show axially‐symmetric g and A ^Cu tensors suggesting a nearly planar co‐ordination within the binuclear host complexes. Diamagnetically diluted Cu^II/Cd^II powder samples could not be prepared. In the EPR spectra of the pure binuclear Cu^II‐complex exchange‐coupled Cu^II‐Cu^II pairs were observed. According to the large Cu^II‐Cu^II distance of about 7,50Å a small fine structure parameter D = 26·10^?4 cm^?1 is observed; T‐dependent EPR measurements down to 5 K reveal small antiferromagnetic interactions for the Cu^II‐Cu^II dimer. Besides of the dimer in the EPR spectra the signals of a mononuclear Cu^II species are observed whose concentration is T‐dependent. This observation can be explained assuming an equilibrium between the binuclear Cu^II‐complex (Cu^II‐Cu^II pairs) and oligomeric complexes with “isolated” Cu^II ions.     

Zur Struktur und Reaktivität des Diammoniumhexafluoromanganats(IV)

About the Structure and Reactivity of Diammonium Hexafluoromanganate(IV) Electrolytic oxidation of an aqueous suspension of MnF₂ containing NH₄F, and subsequent crystallization in 40% HF yields yellow crystals of (NH₄)₂MnF₆. It crystallizes in the hexagonal K₂MnF₆ type structure with the space group P6₃mc and a = 5.903; c = 9.565 Å; Z = 2. With in situ powder diffraction studies it is shown, that (NH₄)₂MnF₆ is gradually reduced in a NH₃ atmosphere between 30 and 230 °C to afford (NH₄)₃MnF₆, (NH₄)₂MnF₅, and finally NH₄MnF₃. (NH₄)₃MnF₆, thereby, forms a hitherto unknown cubic (a = 9.082 Å) high temperature modification with the cryolite type structure. Under N₂ the thermal decomposition of (NH₄)₂MnF₆ proceeds via NH₄MnF₄ to yield MnF₂.