Anna L. Sudlow

Nanostructured Hybrid Polymer−Inorganic Solar Cell Active Layers Formed by Controllable in Situ Growth of Semiconducting Sulfide Networks

Nanostructured composites of inorganic and organic materials are attracting extensive interest for electronic and optoelectronic device applications. In this paper, we introduce a general method for the fabrication of metal sulfide nanoparticle/polymer films employing a low-cost and low temperature route compatible with large-scale device manufacturing. Our approach is based upon the controlled in situ thermal decomposition of a solution processable metal xanthate precursor complex in a semiconducting polymer film. To demonstrate the versatility of our method, we fabricate a CdS/P3HT nanocomposite film and show that the metal sulfide network inside the polymer film assists in the absorption of visible light and enables the achievement of high yields of charge photogeneration at the CdS/P3HT heterojunction. Photovoltaic devices based upon such nanocomposite films show solar light to electrical energy conversion efficiencies of 0.7% under full AM1.5 illumination and 1.2% under 10% incident power, demonstrating the potential of such nanocomposite films for low-cost photovoltaic devices.

Direct Growth of Metal Sulfide Nanoparticle Networks in Solid‐State Polymer Films for Hybrid Inorganic–Organic Solar Cells

Hybrid metal sulfide/polymer solar cell active layers are fabricated employing an approach based upon the in-situ thermal decomposition of a single source metal xanthate precursor in a semiconducting polymer film. The nanomorphology of the film, the charge photogeneration yield at the donor-acceptor heterojunction and device performance are shown to be dependent upon the annealing temperature. Photovoltaic devices based upon such layers are shown to exhibit power conversion efficiencies of 2.2% under AM1.5 solar illumination thus demonstrating the potential of such nanocomposite films for photovoltaic device applications.

Formation of PbS materials from lead xanthate precursors

Six lead xanthate adducts Pb(S(2)COR)(2).L [R = Et, (n)Bu, L = bipy, TMEDA (tetramethylethylenediamine), PMDETA (pentamethyldiethylenetriamine)] have been synthesised and the structures of all, save Pb(S(2)COBu(n))(2).TMEDA (4) which is an oil, determined. Pb(S(2)COEt)(2).TMEDA (3) is seven-coordinate at lead through three chelating ligands and one weak intermolecular Pb‥S interaction. Both Pb(S(2)COR)(2).bipy [R = Et (1), (n)Bu (2)] are dimers in which one xanthate is terminal and the other μ(2) bridging at each sulphur, generating an eight-coordinate lead when the bipy donor is included. Both Pb(S(2)COR)(2).PMDETA [R = Et (5), (n)Bu (6)] are seven-coordinate at lead by virtue of two bidentate chelating xanthate ligands and a tridentate PMDETA; there are no intermolecular interactions. Trends in the (207)Pb NMR chemical shifts mirror the changes in the intramolecular coordination number across the series. Pb(S(2)COEt)(2).TMEDA (3) has been used to deposit PbS films on glass, Mo-coated glass and Si by AACVD. Pb(S(2)COEt)(2) also generated PbS nanocubes when decomposed under an autogenerated pressure.

Solution-Processed Mesoscopic Bi2S3:Polymer Photoactive Layers

The fabrication of solution-processed nontoxic mesoporous Bi2S3 structures is demonstrated and the suitability of these structures for use in hybrid solar cells investigated. Mesoporous Bi2S3 electrodes are prepared via thermal decomposition of a thin film composed of a bismuth xanthate single source precursor. The resultant Bi2S3 films are made up of regular needles with approximate dimensions of 50×500 nm, as confirmed by scanning electron microscopy (SEM). The crystallinity of the Bi2S3 is found to be dependent on the annealing temperature, as determined by X-ray diffraction. The porous Bi2S3 films are infiltrated with the hole conductor P3HT to generate novel hybrid films, and laser-based transient absorption spectroscopy is used to interrogate the charge-separation reaction at the resulting Bi2S3/P3HT heterojunction. Specifically, optical excitation of the hybrid films results in efficient and long-lived charge separation (microsecond to millisecond timescale), thereby rendering such films suitable for the development of novel low-cost solar-energy conversion devices.

Thermal decomposition of solution processable metal xanthates on mesoporous titanium dioxide films: a new route to quantum-dot sensitised heterojunctions

We introduce a straightforward route to the fabrication of metal sulfide semiconductor (e.g. CdS, Sb(2)S(3), Bi(2)S(3)) sensitised TiO(2) films. Our approach is based upon the controllable thermal decomposition of a single-source metal xanthate precursor on a mesoporous metal oxide film. The growth of the metal sulfide deposit is confirmed by Raman and UV-Vis steady-state absorption measurements. Transient absorption spectroscopy measurements provide evidence for charge separation across the metal sulfide/TiO(2) interface. Moreover, a high yield of long-lived photogenerated charges is observed in a three-component TiO(2)/metal sulfide/spiro-OMeTAD film, thus demonstrating the potential of such multicomponent films for solar energy conversion devices.

Persistence of C–H⋯π(chelate ring) interactions in the crystal structures of Pd(S2COR)2. The utility of Pd(S2COR)2 as precursors for palladium sulphide materials

The crystallographic structures of 12 palladium xanthates, Pd(S2COR)2 (R = alkyl) show a uniform adoption of square-planar PdS4 geometries. Supramolecular aggregation in 1 (R = Me), 2 (Et) and 3 (n-Pr) is based on secondary Pd⋯S interactions, which are “turned off” when the bulk of R increases. In 4 (i-Pr), C–H⋯S hydrogen bonding is present. In each of 2–4, C–H⋯π(PdS2C) interactions are incorporated within the architecture, stabilised by Pd⋯S secondary- or C–H⋯S hydrogen-bonding. In 5–12 (R = n-Bu, i-Bu, n-Pent, i-Pent, neoPent, n-Hex, i-Hex, neoHex), varying numbers of stand-alone C–H⋯π(PdS2C) interactions involving different hydrogen donors uniformly stabilise supramolecular chains in their crystal structures. In order to determine the relative importance of the various intermolecular interactions and packing effects, a computational study using dispersion-corrected density-functional theory was performed on 3 (R = n-Pr). The results showed that the most significant contributors to the stability of the crystal structure are Pd⋯S interactions followed closely by C–H⋯π(PdS2C) interactions. Two non-specific hydrophobic interactions also contribute to the overall packing to a lesser extent. The utility of Pd(S2COR)2 to function as synthetic precursors for PdS nanoparticles and thin films was also investigated. Aerosol-assisted-CVD on representative examples generated PdS films with either matted, needle-like or granular morphologies depending on temperature and substrate. Solvothermal (ethylene glycol) decomposition generated sulphur-rich PdS nanoparticles with diameters 120 nm (7 and 10)–400 nm (8). When dodecanethiol was employed as a capping agent, PdS1.75 nanoparticles <10 nm were generated from 1.

Inorganic and Organozinc Fluorocarboxylates: Synthesis, Structure and Materials Chemistry

The organozinc fluorocarboxylates RZnO2CRf and RZnO2CRf·TMEDA, along with Zn(O2CRf)2·TMEDA (R = Me, Et; Rf = C2F5, C3F7) have been synthesized. The structures of EtZnO2C2F5 (5), EtZnO2C3F7 (7), EtZnO2C2F5·TMEDA (11), Zn(O2C2F5)2·TMEDA (13), along with products from the adventitious reaction with either O2 or H2O, Zn10Me4(OMe)4(O2CC2F5)12 (2), Zn9Et2(O2CC2F5)12(O)2 (6), Zn8Et4(OEt)4(O2CC3F7)6(O) (8), [Zn(O2CC3F7)2·TMEDA]2·H2O (15) have been determined. Thin films of oriented ZnO have been deposited on glass substrates by low-pressure chemical vapor deposition (LPCVD) using 3 and 10 as precursors, though no fluorine incorporation in the films was noted. LPCVD using 13 as precursor also yielded fluorine-free ZnO, but lacking the oriented growth observed using 3, 10. However, 5, which exhibits short intermolecular Zn···F contacts in the solid state, thermally decomposes to bulk ZnF2.

New multi-ferrocenyl- and multi-ferricenyl- materials via coordination-driven self-assembly and via charge-driven electro-crystallization

Three new tetra-ferrocenylethynylpyridinyl copper complexes, L4(CuI)4 (3), L4(CuBr)2 (4), and L4(CuCl)2 (5) have been prepared from the reaction of ferrocenylethynylpyridine (L)(2) with copper halides CuX (with X = I(-), Br(-), Cl(-)).The ligand 2 and the complexes 3-5 have been fully characterized by spectroscopic methods. The structures of 2-4 have been confirmed by single-crystal X-ray crystallography. 2 forms a dimer in the crystalline-state through C-H··N hydrogen bonds. 4 and 5 are dimers and 3 a tetramer, in all cases linked through Cu-X··Cu bridging interactions. Cyclic voltammetry in dichloroethane showed chemically reversible multiferrocenyl oxidation signals with evidence for product electro-crystallization. The oxidation products were isolated by electrodeposition onto a Pt disc electrode and investigated by scanning electron microscopy which confirmed the spontaneous formation of crystalline oxidation products with distinctive morphologies. Energy dispersive X-ray elemental analysis shows the presence of hexafluorophosphate (counterion) with the P:Fe ratio of 1:1, 0.5:1, and 1:1 for the electrocrystallized products 3, 4, and 5, respectively, suggesting the formulas [3](4+)(PF6(-))4, [4](2+)(PF6(-))2, and [5](4+)(PF6(-))4 for the electro-crystallized products.

The synthesis and reaction chemistry of new amino-functionalised tin(ii) alkoxides

Sn(ii) derivatives of the aminoalcohols (t)Bu(H)NC(Me)(H)CH(2)OH (Htbap, ), (R(1)R(2)NCH(2))(2)C(H)OH (R(1) = R(2) = Me, , Hbdmap; R(1) = (t)Bu, R(2) = H, , Hbtbap), (R(1)R(2)NCH(2))(3)COH (R(1) = R(2) = Me, , Htdmap; R(1) = (t)Bu, R(2) = H, , Httbap) have been synthesised by reaction of the alcohol with Sn[N(SiMe(3))(2)](2). The structures of the ligands , .H(2)O, along with Sn(ttbap)(2) have been determined; the latter is pseudo-trigonal bipyramidal with nitrogen atoms in axial sites and oxygen atoms and a stereochemically-active lone pair in the equatorial positions. Sn(ttbap)(2) reacts with Fe(2)(CO)(9) in 2 : 1 ratio (Sn : Fe = 1 : 1) to afford the donor-acceptor complex (ttbap)(2)Sn:-->Fe(CO)(4), while in 1 : 1 ratio (Sn : Fe = 1 : 2) the Sn(0) complex (Httbap)Sn[Fe(CO)(4)](2) is formed, in which Httbap is a neutral zwitterionic form of the ligand. The structures of both bimetallic species are reported. Thermal decomposition of (Httbap)Sn[Fe(CO)(4)](2) under low-pressure CVD conditions gives a film containing a mixture of cubic-Sn, cubic-Fe and the hexagonal intermetallic phase Fe(3)Sn.

Synthesis and structures of Cu-Cl-M adducts (M=Zn, Sn, Sb)

Abstract The novel bimetallic adducts [(Ph3P)2CuCl]2.ZnCl2 (1), {[(Me3P)CuCl]2.ZnCl2}n (2), [(Me3P)4Cu]+[(Me3P)2Cu(Cl)2ZnCl2]- (3), (Ph3P)2CuCl.SnCl2 (4), (Me3P)3CuSnCl3 (5), [(Ph3P)2CuCl.SbCl3]2 (6) and (Ph3P)3CuCl.SbCl3 (7) have been synthesized from combinations of R3P, CuCl and one of ZnCl2, SnCl2 or SbCl3, and their structures were determined. [(Me3P)2Cu]+[HPMe3]2+[Sb2Cl9]3- (8) and [(Me3P)4Cu]+[(Me3P)2Sb2Cl7]- (9) have been isolated as minor by-products from the reaction of Me3P, CuCl and SbCl3, and their structures were also determined.