The Experts below are selected from a list of 42768 Experts worldwide ranked by ideXlab platform

Denis Andrienko - One of the best experts on this subject based on the ideXlab platform.

Emilio Palomares - One of the best experts on this subject based on the ideXlab platform.

  • High open circuit voltage in efficient thiophene-based small molecule solution processed Organic Solar Cells
    Organic Electronics, 2013
    Co-Authors: Nuria F. Montcada, Beatriz Pelado, Aurelien Viterisi, Jorge Albero Silvestre, Julieta Coro, Pilar De La Cruz, Fernando Langa, Emilio Palomares
    Abstract:

    We have synthesized and fully characterized an oligothiophene small Organic molecule for its use as electron donor moiety in solution processed bulk-heterojunction Organic Solar Cells. Our results show that device solvent annealing process of the conjugated oligothiophene molecule leads to a light-to-energy conversion efficiency of 3.75% under standard illumination conditions. The Solar cell presents open-circuit voltage and fill factors as high as 1.01 V and 63.05% respectively, which are among the highest values obtained for small molecule solution processed Organic Solar Cells.

Pwm Paul Blom - One of the best experts on this subject based on the ideXlab platform.

  • Semitransparent Organic Solar Cells with Organic wavelength dependent reflectors
    Applied Physics Letters, 2011
    Co-Authors: Yulia Galagan, Michael G. Debije, Pwm Paul Blom
    Abstract:

    Semitransparent Organic Solar Cells employing solution-processable Organic wavelength dependent reflectors of chiral nematic (cholesteric) liquid crystals are demonstrated. The cholesteric liquid crystal (CLC) reflects only in a narrow band of the Solar spectrum and remains transparent for the remaining wavelengths. The reflective band is matched to the absorption spectrum of the Organic Solar cell such that only unabsorbed photons that can contribute to the photocurrent are reflected to pass through the active layer a second time. In this way, the efficiency of semitransparent Organic Solar Cells can be enhanced without significant transparency losses. An efficiency increase of 6% was observed when a CLC reflector with a reflection band of 540–620 nm was used, whereas the transparency of the Organic Solar Cells is only suppressed in the 80 nm narrow bandwidth.

Steve Albrecht - One of the best experts on this subject based on the ideXlab platform.

  • impact of charge transport on current voltage characteristics and power conversion efficiency of Organic Solar Cells
    Nature Communications, 2015
    Co-Authors: Steve Albrecht, Dieter Neher, Uli Wurfel, Annika Spies
    Abstract:

    This work elucidates the impact of charge transport on the photovoltaic properties of Organic Solar Cells. Here we show that the analysis of current–voltage curves of Organic Solar Cells under illumination with the Shockley equation results in values for ideality factor, photocurrent and parallel resistance, which lack physical meaning. Drift-diffusion simulations for a wide range of charge-carrier mobilities and illumination intensities reveal significant carrier accumulation caused by poor transport properties, which is not included in the Shockley equation. As a consequence, the separation of the quasi Fermi levels in the Organic photoactive layer (internal voltage) differs substantially from the external voltage for almost all conditions. We present a new analytical model, which considers carrier transport explicitly. The model shows excellent agreement with full drift-diffusion simulations over a wide range of mobilities and illumination intensities, making it suitable for realistic efficiency predictions for Organic Solar Cells.

  • Inverted Organic Solar Cells comprising low-temperature-processed ZnO films
    Applied Physics A, 2014
    Co-Authors: Basudev Pradhan, Steve Albrecht, Burkhard Stiller, Dieter Neher
    Abstract:

    Inverted Organic Solar Cells are fabricated using low-temperature-annealed ZnO film as an electron transport layer. Uniform ZnO films were prepared by spin coating a diethylzinc (DEZ) precursor solution in air, followed by annealing at 100 °C. Organic Solar Cells prepared on these ZnO films with a 1:1 P3HT:PCBM blend as the active layer show a high power conversion efficiency of 4.03 %, which is more than 10 % higher than the PCE of Solar Cells comprising ZnO prepared via a high-temperature sol–gel route.

Xinliang Feng - One of the best experts on this subject based on the ideXlab platform.

  • Thiophene-based conjugated oligomers for Organic Solar Cells
    Journal of Materials Chemistry, 2011
    Co-Authors: Fan Zhang, Youyong Xu, Dongqing Wu, Xinliang Feng
    Abstract:

    Owing to their efficient light harvesting, structural versatility and intrinsic charge transport behavior, thiophene-based p-conjugated systems have attracted much attention in developing high performance Organic Solar Cells. In comparison to the relevant conjugated polymers that are used as active materials in photovoltaic devices, conjugated oligomers possess some critical advantages: (1) well-defined molecular structures lead to their synthetic reproducibility with high purity which is vital to obtain repeatable device performance; (2) crystalline features of oligomers favor the long range order in the solid state and benefit the charge carrier transport; (3) the devices can be readily fabricated by both solution-processable and vacuum-deposited techniques. In this feature article, thiophene-based conjugated oligomers with molecular architectures from 1D to 3D, which play an essential role in the device performance of Organic Solar Cells, will be summarized. We aim to address the influence of the thiophene motifs on the electronic, optical and self-assembly properties of the materials, and eventually conclude the relationship between the molecular structures and photovoltaic properties.