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ZnO thin film was fabricated on tin-doped indium oxide electrode as an electron selective layer of inverted polymer solar cells using magnetron sputtering deposition. Ionic liquid-functionalized carbon nanoparticles (ILCNs) film was further deposited onto ZnO surfaces by drop-casting ILCNs solution to improve interface properties. The power conversion efficiency (PCE) of inverted polymer solar cells (PSCs) with only ZnO layer was quickly decreased from 2.7% to 2.2% when the thickness of ZnO layer was increased from 15 nm to 60 nm. However, the average PCE of inverted PSCs with ZnO layer modified with ILCNs only decreased from 3.5% to 3.4%, which is comparable to that of traditional PSCs with poly(3,4- ethylenedioxythiophene)/poly(styrenesulfonate) anode buffer layer. The results suggested that the contact barrier between ZnO layer and poly(3-hexylthiophene) and phenyl-C61-butyric acid methylester (P3HT:PCBM) blended film compared to ZnO bulk resistance can more significantly influence the performance of inverted PSCs with sputtered ZnO layer. The vanishment of negative capacitive behavior of inverted PSCs with ILCNs modified ZnO layer indicated ILCNs can greatly decrease the contact barrier of ZnO/P3HT:PCBM interface. [ABSTRACT FROM AUTHOR]

We explore a simple and eco-friendly approach for preparing CZTS powders and a screen-printing process for Cu2ZnSn(S,Se)4 (CZTSSe) counter electrodes (CEs) in dye-sensitized solar cells (DSCs). Cu2ZnSnS4 (CZTS) nanoparticles have been synthesized via a hydrazine-free solvothermal approach without the assistance of organic ligands. CZTS has been prepared by directly drop-casting the CZTS ink on the cleaned FTO glass, while CZTSSe CEs have been fabricated by screen-printing CZTS pastes, followed by post selenization using Se vapor obtained from elemental Se pellets. The crystal structure, composition and morphology of the as-deposited CZTS nanoparticles and CZTSSe electrodes are characterized by X-ray diffractometer, energy dispersive spectrometer, field emission scanning electron microscopy and transmission electron microscopy. The electrochemical properties of CZTS, CZTSSe and Pt CE based DSCs are examined and analyzed by electrochemical impedance spectroscopy. The prepared CZTS and CZTSSe CEs exhibit a cellular structure with high porosity. DSCs fabricated with CZTSSe CEs achieve a power conversion efficiency of 5.75% under AM 1.5 G illumination with an intensity of 100 mW/cm2, which is higher than that (3.22%) of the cell using the CZTS CE. The results demonstrate that the CZTSSe CE possesses good electrocatalytic activity for the reduction of charge carriers in electrolyte. The comprehensive CZTSSe CE process is cheap and scalable. It can make large-scale electro-catalytic film fabrication cost competitive for both energy harvesting and storage applications. [ABSTRACT FROM AUTHOR]

Polymer gel electrolytes based on poly(acrylic acid)-poly(ethylene glycol) (PAA-PEG) hybrid have been prepared and applied to developed quasi-solid-state dye-sensitized solar cells (DSCs). PAA-PEG hybrid was synthesized by polymerization reaction. Quasi-solid-state DSCs were fabricated with synthesized PAA-PEG electrolyte. The effects of alkali iodides LiI, KI, and I concentrations on liquid electrolyte absorbency and ionic conductivity of PAA-PEG were investigated. The evolution of the solar cell parameters with polymer gel electrolyte compositions was revealed. DSCs based on PAA-PEG with optimized KI/I concentrations showed better performances than those with optimized LiI/I concentrations. The electrochemical impedance spectroscopy technique was employed to examine the electron lifetime in the TiO electrode and quantify charge transfer resistances at the TiO/dye/electrolyte interface and the counter electrode in the solar cells based on the PAA-PEG hybrid gels. A maximum conversion efficiency of 4.96% was obtained for DSCs using KI based quasi-solid electrolyte under 100 mW cm. Our work suggests that KI can be the promising alkali metal iodide for improving the performance of PAA-PEG hybrid gel DSCs. [ABSTRACT FROM AUTHOR]

Herein we report a novel, environment-friendly approach for the reduction of graphene oxide by means of incorporating visible-light sensitive TiO2 and steady state visible-light irradiation. The surface morphology and fine structure of as-prepared composites were characterized by scanning electron microscopy and atomic force microscopy, respectively. The reduction process was evidenced by variation of conductivity. In addition, some of the electrochemical properties of the resultant graphene materials have been investigated as well. [ABSTRACT FROM AUTHOR]

Abstract  A new type of 18-metallacrown-6, [Fe6(H2O)6L6] (L = 1-(2-hydroxy-benzoyl)-thiosemicarbazide), has been prepared and characterized. The backbone of this metal-organic assembly is the double-azathiacrown, which is formed by six repeating units of the five-membered rings [Fe–S–C–N–N]. It is the first metal complex containing a double-azathiacrown. Due to the meridional coordination of the ligand to the Fe3 ion, the ligand enforces the stereochemistry of the Fe3 ions as a propeller configuration with alternating Λ/Δ forms. Antibacterial screening data showed that the metallacrown has strong antimicrobial activity against Escherichia coli and Staphylococcus aureus. [ABSTRACT FROM AUTHOR]

Growth of carbon nanotube (CNT) films with good field emission properties on glass is very important for low cost field emission display (FED) applications. In addition to Ni, Co and Fe, Cu can be a good catalyst for CNT growth on glass, but due to diffusion into SiO2 it is difficult to control the CNTs density and uniformity. In this paper, four metal barrier layers (W, Ni, Cr, Ti) were deposited by dc magnetron sputtering on glass to reduce the Cu diffusion. As-grown CNT films showed various morphologies with the use of different barrier metals. CNTs with uniform distribution and better crystallinity can be synthesized only on Ti/Cu and W/Cu. Voltage current measurements indicate that better field emission properties of CNT films can be obtained on titanium and tungsten barriered Cu, while chromium and nickel are not suitable barrier candidates for copper in CNT-FED applications because of the reduced emission performance. [ABSTRACT FROM AUTHOR]