Ein weiterer wichtiger, die Leistung einer Solarzelle begrenzender Parameter ist deren Diffusionsspannung built-in potential, VBi. Within the range of semiconducting pn-junctions, Mott—Schottky analysis is an established method to determine the built-in potential. Correct determination of charge transfer state energy from luminescence spectra in organic solar cells List, M. Improved efficiency of bulk heterojunction hybrid solar cells by utilizing CdSe quantum dot-graphene nanocomposites Eck, M. Experimental findings as well as the contradictions to Mott—Schottky theory indicated, that a direct transfer of this method to organic photovoltaics is not appropriate. Please always quote using this URN:
Diese wird im letzten Teil der Arbeit anhand der ZnPc: After investigation of the optoelectronic properties and the influence of the different structural modifications on the molecular properties, suitable candidates will be tested as donor materials in BHJSC. The first approach will be based on a previous project dealing with the synthesis of a series of oligothiophenes consisting of an A-D-A system comprising a central dithieno[3: In case of organic bulk heterojunction BHJ solar cells it is — in contrast to inorganic devices — dependent on the applied bias voltage. Within a series of eleven different fullerenes, multi-substituted fullerenes as well as Cbased fullerenes are observed not to undergo dimerization, in contrast to all mono-substituted Cfullerenes. This junction can be realized by two distinct layers forming a planar heterojunction or by an intermixed film of donor and acceptor, resulting in a bulk heterojunction.
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Controlling the intragap states of electron transporting interlayers for efficient and stable inverted organic photovoltaics Bai, S. Donor-acceptor oligomers for application in organic solar cells: Photo-induced absorption spectroscopy reveals that the enhanced degradation of C-PCPDTBT correlates with the population of the polymer triplet state via the polymer: C60 Solar Cells Author s All words At least one word None of the words.
After this macroscopic view on the photocurrent, the focus of this work moves to the more basic processes determining the photocurrent: Furthermore, the electronic structure of the A-D-A scaffold should be modified by the replacing the DCV acceptor moieties by 1- 1,1-dicyanomethylene -cyclohexene DCC units, in order to shift the absorption towards longer wavelength for an enhanced light harvest.
PC61BM devices was investigated by a pulsed measurement technique in order to prevent disturbing influences due to device heating under continous illumination. Improved efficiency of bulk heterojunction hybrid solar cells by utilizing CdSe quantum dot-graphene nanocomposites Eck, M.
The voltage dependence results in a reduced fill factor and thus an even more pronounced influence of the photocurrent on the device efficiency.
The work is completed by a simulation study of the influence of charge-carrier mobilities and different recombination processes on the J-V curve and an identification of a photoshunt dominating the experimental linear photocurrent-voltage characteristics in reverse bias. The physical meaning of charge extraction by linearly increasing voltage transients from organic solar cells Hanfland, R.
Pz Photoconduction and photovoltaic effects. We find that fullerenes do not only influence the solar cell lifetime by stabilizing or destabilizing the pi-conjugated polymer against solarzdlle, but they are also able to cause direct device degradation by undergoing organlsche under inert atmosphere. Numerical simulations and advanced characterization of organic solar cells Spies, Annika; Weber, Eicke R.
Finally, the formation of different photogenerated species and their kinetics in PC60BM films and blends with polymer is studied by ultrafast transient absorption spectroscopy. The second part of this work deals with the photo-degradation of organic photovoltaics under inert atmosphere. A comparison of experimental and simulation data indicates that solarelle reason is a changed donor-acceptor energy gap caused by a shift of the ionization potential of ZnPc.
Finally, we perform calculations to quantify the solarzdlle effect by optical screening, and demonstrate it to play only a minor role as well. This disxertation focuses on the electrical processes in organic solar cells developing and employing a one-dimensional drift-diffusion model.
Charge carrier selectivity for contacts for organic solar cells Spies, A. These findings were set into relation to current—voltage characteristics in order to discuss the origin of the clear differences in the solar cell performance of both materials. As it was originally derived for abrupt pn-junctions, its validity for organic BHJ solar cells — a bipolar, effective medium — was discussed.
Barriers and Schottky contacts. A fullerene LUMO level of It is evidenced that quenching of the polymer singlet-excited states does not lead to a significant stabilization. Within the range dlssertation semiconducting pn-junctions, Mott—Schottky analysis is an established method to determine the built-in potential. That is why several OPV startup companies were launched in the last decade.
Die entsprechenden Ergebnisse wurden dann in Relation zu den Strom—Spannungs-Kennlinien gesetzt, um die deutlichen Unterschiede in der Effizienz der Solarzellen zu diskutieren. Reiternavigation Alle ausklappen Alle einklappen. It is therefore crucial to understand the underlying processes determining the photocurrent in order to be able to further zolarzelle the solar cell performance.
Experiments and simulations Reinhardt, J. Organic solar cells consist of hydrocarbon compounds, deposited as ultrathin layers some tens of nm on a substrate. Electrodes are attached to the absorber to collect the charges by providing an ohmic contact in the optimum case. Positive side of disorder: C60 Bulk Heterojunction Solar Cells 9.