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A series of allyl-functionalized imidazolium salts are reported, including 1-allyl-3-ethylimidazolium iodide and 1-allyl-3-propylimidazolium iodide, which have melting points close to room temperature and show typical properties of supercooled fluids if heated above their melting points. Their viscosities in the liquid state are considerably lower than the benchmark ionic liquid used in solar cells, viz., 1-propyl-3-methylimidazolium iodide. Electrolytes containing these new liquids provide excellent efficiencies and good stability in dye-sensitized solar cells when subjected to an accelerated-light soaking test at 60 °C. The structures of three of the new salts have been established in the solid state by single-crystal X-ray analysis. [ABSTRACT FROM AUTHOR]

Two metal-free organic sensitizers containing two N,N-diethylaniline (DEA) moieties and a twisted 1,1,2,2-tetraphenylethene (TPE) structure, dye SD with one anchoring group and dye DD with two anchoring groups, were synthesized and applied in dye-sensitized solar cells (DSSCs). The introduction of a nonplanar TPE structure was used to form a series of propeller-like structures and reduce the tendency of dyes to randomly aggregate on TiO2 surface, but without importing an aggregation-induced emission (AIE) property. The thermal stabilities, UV-vis absorption spectra, electrochemical properties, and photovoltaic parameters of DSSCs with these two dyes were systematically studied and compared with each other. The overall conversion efficiencies (η) of 4.56% for dye SD and 6.08% for dye DD were obtained under AM 1.5 G irradiation. [ABSTRACT FROM AUTHOR]

We present a novel “brick and mortar” strategy for creating highly efficient transparent TiO2coatings for photocatalytic and photovoltaic applications. Our approach is based on the fusion of preformed titania nanocrystalline “bricks” through surfactant-templated sol−gel titania “mortar”, which acts as a structure-directing matrix and as a chemical glue. The similar chemical composition of both bricks and mortar leads to a striking synergy in the interaction of crystalline and amorphous components, such that crystallization is enhanced upon thermal treatment and highly porous and highly crystalline structures are formed at very mild conditions. Coatings with a broad variety of periodic mesostructures and thicknesses ranging from few nanometers to several micrometers are accessible using the same organic template, and the final structures are tunable by varying the fraction of the “bricks”. The beneficial combination of crystallinity and porosity leads to greatly enhanced activity of the films in photocatalytic processes, such as the photooxidation of NO. Acting as the active layers in dye-sensitized solar cells, films of only 2.7 μm in thickness exhibit a conversion efficiency of 6.0%. [ABSTRACT FROM AUTHOR]