We present herein a facile one-step low-temperature hydrothermal approach for in situ growth of metal selenides (Co(0.85)Se and Ni(0.85)Se) on conductive glass substrates. The as-prepared metal selenides on conductive substrates can be used directly as transparent counter electrodes for dye-sensitized solar cells (DSSCs) without any post-treatments. It is found that graphene-like Co(0.85)Se exhibits higher electrocatalytic activity than Pt for the reduction of triiodide. As a consequence, the DSSC with Co(0.85)Se generates higher short-circuit photocurrent and power conversion efficiency (9.40%) than that with Pt.

The durability and reactivity of catalysts can be effectively and precisely controlled through the careful design and engineering of their surface structures and morphologies. Herein, we develop a novel "adsorption-calcination-reduction" strategy to synthesize spinel transitional metal oxides with a unique necklace-like multishelled hollow structure exploiting sacrificial templates of carbonaceous microspheres, including NiCoO (NCO), CoMnO, and NiMnO. Importantly, benefiting from the unique structures and reduction treatment to offer rich oxygen vacancies, the unique reduced NCO (R-NCO) as a bifunctional electrocatalyst exhibits the dual characteristics of good stability as well as high electrocatalytic activity for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). At 1.61 V cell voltage, a 10 mA cm water splitting current density is obtained from the dual-electrode, alkaline water electrolyzer. Calculations based on density functional theory (DFT) reveal a mechanism for the promotion of the catalytic reactions based on a decrease in the energy barrier for the formation of intermediates resulting from the introduction of oxygen vacancies through the reduction process. This method could prove to be an effective general strategy for the preparation of complex, hollow structures and functionalities.

Metal wires suffer from corrosion in fiber-shaped dye-sensitized solar cells (DSSCs). We report herein that stable, ultrastrong, and highly flexible aligned carbon nanotube fibers can be used not only as catalytic counter electrodes but also as conductive materials to support dye-loaded TiO(2) nanoparticles in DSSCs. The power conversion efficiency of this fiber solar cell can achieve 2.94%. These solar power fibers, exhibiting power conversion efficiency independent of incident light angle and cell length, can be woven into textiles via a convenient weaving technology.

A sandwich-like 2D-mesoporous-carbon/MoS -nanosheet heterostructure is fabricated for the first time. The hybrid structure is composed of three well-stacked monolayers: an ordered-mesoporous-carbon monolayer, a MoS monolayer, and a further ordered-mesoporous-carbon monolayer. This unique heterostructure exhibits excellent electrochemical performance as an anode material for lithium-ion batteries.

No abstract

Nickel diselenide (NiSe(2)) has been synthesized and applied as a counter electrode (CE) of dye-sensitized solar cells (DSSCs) for the first time, which displays remarkable catalytic activity in the reduction of I(3)(-). The DSSC with a NiSe(2) CE produces a higher power conversion efficiency (8.69%) than that (8.04%) of the cell with a Pt CE under the same conditions. A new method for comparing the catalytic activity has also been proposed.

Since their discovery by O'Regan and Grätzel in 1991, [1] dyesensitized solar cells (DSSCs) have attracted considerable interest [2] because of their low production cost, high power conversion efficiency (η), and environmental friendliness. Although an η over 11% has been recorded for DSSCs with volatile organic liquid electrolytes, [3] they may be inhibited for outdoor applications in view of the need for robust encapsulation. Therefore, considerable efforts have been devoted to developing solid electrolytes for the fabrication of solid-state DSSCs (ssDSSCs). [4][5][6][7][8][9][10][11][12] However, the efficiency of ssDSSCs is still unsatisfactory compared with liquid junction DSSCs. The low conductivity and/or incomplete filling of solid electrolytes containing a I − /I 3 − redox couple in mesoporous TiO 2 films usually lead to a lower shortcircuit photocurrent (J sc ), open-circuit photovoltage (V oc ), and fill factor (FF). [13,14] Therefore, the development of novel solid electrolytes with high ionic conductivity and good pore filling property is of fundamental importance for highly efficient ssDSSCs.Imidazolium-based ionic liquids have been proven to be promising materials as liquid electrolytes for high-performance DSSCs because of their wide electrochemical window, high electrical conductivity, negligible vapor pressure, and nontoxicity. [15] However, they are still a type of liquid material and leakage during long-term operation is unavoidable. To overcome these shortcomings and retain the advantage of the imidazolium structure, the liquid-state phase of imidazolium-based ionic liquids has been transformed into a solid state by raising their melting points over room temperature. [16] Unfortunately, the conductivities of the reported imidazolium salts with a solid phase and the efficiencies of their ssDSSCs are still low.In this communication, we report for the first time a novel class of ester-functionalized ionic conductors based on an imidazolium cation and iodide anion (Figure 1a) for use in ssDSSCs. Such ester-functionalized solid state electrolytes possess advantages over inorganic [17] and organic hole conductors.[18] Firstly, ester functionalized ionic conductors can form a three-dimensional (3D) ionic channel of iodides, which is advantageous for fast movement of iodides and charge transfer along the polyiodide chain. Secondly, the coordination interactions between esters and Li + ions (typically used cations in DSSCs) can form dimers of conductor molecules, and thus the distance of adjacent polyiodides is reduced, resulting in faster charge transfer and higher conductivity. In addition, the smaller size of the ester-functionalized ionic conductors, as compared to the polymer electrolytes, [8,19] permits a deep penetration of the electrolytes into the porous TiO 2 films, which facilitates the reduction of the oxidized dye molecules and favors high photocurrent generation.Herein, ssDSSCs were constructed using solid electrolytes based on ionic conductors 1-5 with a metal-free organic dye ( Figure...

Room-temperature sodium-ion batteries have attracted great attentions for large-scale energy storage applications in renewable energy. However, exploring suitable anode materials with high reversible capacity and cyclic stability is still a challenge. The VS 4 , with parallel quasi-1D chains structure of V 4+ (S 2 2− ) 2 , which provides large interchain distance of 5.83 Å and high capacity, has showed great potential for sodium storage. Here, the uniform cuboid-shaped VS 4 nanoparticles are prepared as anode for sodium-ion batteries by the controllable of graphene oxide (GO)-template contents. It exhibits superb electrochemical performances of high-specific charge capacity (≈580 mAh·g −1 at 0.1 A·g −1 ), long-cycle-life (≈98% retain at 0.5 A·g −1 after 300 cycles), and high rates (up to 20 A·g −1 ). In addition, electrolytes are optimized to understand the sodium storage mechanism. It is thus demonstrated that the findings have great potentials for the applications in high-performance sodium-ion batteries.