The Experts below are selected from a list of 24522 Experts worldwide ranked by ideXlab platform

Dirk M. Guldi - One of the best experts on this subject based on the ideXlab platform.

  • iodine pseudohalogen ionic liquid based electrolytes for quasi Solid State dye sensitized solar cells
    ACS Applied Materials & Interfaces, 2017
    Co-Authors: Annkatrin Lennert, Michelle Sternberg, Rubén D. Costa, Karsten Meyer, Dirk M. Guldi
    Abstract:

    In the current work, novel symmetrically alkyl-substituted imidazolium-based ionic liquids have been synthesized featuring either iodide (I–) or selenocyanate (SeCN–) as counteranions. Physicochemical assays based on spectroscopy and electrochemistry techniques have been performed to identify the best ionic liquid for application as electrolytes in quasi-Solid-State dye-sensitized solar cells (qssDSSC). The latter were mixed with additives such as 4-tert-butylpyridine (4tbpy) and guanidinium thiocyanate (GuSCN) to optimize electrode surface coverage, ionic diffusion, and dye regeneration. In addition, we demonstrate that electrolytes containing a mixture of I2 and (SeCN)2 enhance the open-circuit voltage of the final quasi-Solid-State Device by up to 70 mV. As such, iodine-pseudohalogen electrolytes reveal in qssDSSCs a good balance between dye regeneration and hole transport and, in turn, enhance the overall solar energy conversion efficiency by 70% with respect to reference qssDSSCs with iodine-based el...

Lalit Mohan Kandpal - One of the best experts on this subject based on the ideXlab platform.

  • Linking Electronic Transport through a Spin Crossover Thin Film to the Molecular Spin State Using X-ray Absorption Spectroscopy Operando Techniques
    ACS Applied Materials & Interfaces, 2018
    Co-Authors: Filip Schleicher, Michał Studniarek, Kuppusamy Senthil Kumar, Etienne Urbain, Kostantine Katcko, Jinjie Chen, Timo Frauhammer, Marie Herve, Ufuk Halisdemir, Lalit Mohan Kandpal
    Abstract:

    One promising route toward encoding information is to utilize the two stable electronic States of a spin crossover molecule. Although this property is clearly manifested in transport across single molecule junctions, evidence linking charge transport across a Solid-State Device to the molecular film's spin State has thus far remained indirect. To establish this link, we deploy materials-centric and Device-centric operando experiments involving X-ray absorption spectroscopy. We find a correlation between the temperature dependencies of the junction resistance and the Fe spin State within the Device's [Fe(H 2 B(pz) 2) 2 (NH 2-phen)] molecular film. We also factually observe that the Fe molecular site mediates charge transport. Our dual operando studies reveal that transport involves a subset of molecules within an electronically heterogeneous spin crossover film. Our work confers an insight that substantially improves the State-of-the-art regarding spin crossover-based Devices, thanks to a methodology that can benefit Device studies of other next-generation molecular compounds.

Yiyang Li - One of the best experts on this subject based on the ideXlab platform.

  • dynamic tuning of gap plasmon resonances using a Solid State electrochromic Device
    Nano Letters, 2019
    Co-Authors: Yiyang Li, Jorik Van De Groep, Alec A Talin, Mark L Brongersma
    Abstract:

    Plasmonic antennas and metasurfaces can effectively control light–matter interactions, and this facilitates a deterministic design of optical materials properties, including structural color. However, these optical properties are generally fixed after synthesis and fabrication, while many modern-day optics applications require active, low-power, and nonvolatile tuning. These needs have spurred broad research activities aimed at identifying materials and resonant structures capable of achieving large, dynamic changes in optical properties, especially in the challenging visible spectral range. In this work, we demonstrate dynamic tuning of polarization-dependent gap plasmon resonators that contain the electrochromic oxide WO3. Its refractive index in the visible changes continuously from n = 2.1 to 1.9 upon electrochemical lithium insertion and removal in a Solid-State Device. By incorporating WO3 into a gap plasmon resonator, the resonant wavelength can be shifted continuously and reversibly by up to 58 nm...

Muthu K Karuppasamy - One of the best experts on this subject based on the ideXlab platform.

  • a note on fast protonic Solid State electrochromic Device niox ta2o5 wo3 x
    Solar Energy Materials and Solar Cells, 2007
    Co-Authors: A Subrahmanyam, Suresh C Kumar, Muthu K Karuppasamy
    Abstract:

    In the present investigation, the electrochromic properties of a fast protonic Solid State Device: NiOx/Ta2O5/WO3−x prepared at room temperature (300 K) is reported. The non-stoichiometric tungsten oxide thin film is prepared by reactive DC magnetron sputtering technique on ITO coated glass; the oxides of tantalum (∼300 nm) and nickel (∼100 nm) are prepared by electron beam evaporation. This proton Device has a coloration efficiency of ∼82.4 cm2/C and coloration and bleaching time of 6 and 5 s, respectively, and a transmittance variation of 60%. The work function of WO3−x thin films by Kelvin probe in uncolored and colored States are 4.73 and 4.30 eV, respectively.

Daniel T Schwartz - One of the best experts on this subject based on the ideXlab platform.

  • efficient dye sensitized charge separation in a wide band gap p n heterojunction
    Journal of Applied Physics, 1996
    Co-Authors: Brian Oregan, Daniel T Schwartz
    Abstract:

    We report the fabrication and performance of a dye‐sensitized p‐n heterojunction formed from a planar interface between two wide‐band‐gap semiconductors, n‐TiO2 and p‐CuSCN, which contains an intervening monolayer of a sulforhodamine B dye. When exposed to visible light, the photoexcited dye molecules transfer electrons to the n‐TiO2 and holes to the p‐CuSCN. The absorbed‐photon‐to‐current efficiency (APCE) is ≳70% and the open circuit voltage is ≊500 mV. This heterojunction is the Solid‐State analog of the dye‐sensitized photoelectrochemical interfaces used in photography and photovoltaics. The high quantum efficiency and voltage show that it is possible to simultaneously optimize both the dye/n‐type and dye/p‐type interface for efficient forward charge injection and slow charge combination in a Solid‐State Device.