Electronic Structure of Solid-State Dye-Sensitized Solar Cells:
Synchrotron Induced Photoelectron Spectroscopy on Nanocrystalline
TiO2, Newly Developed Dyes and Spiro-MeOTAD.
Technische Universität, Darmstadt
[Ph.D. Thesis], (2014)
Available under Creative Commons Attribution Non-commercial No Derivatives, 2.5.
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|Item Type:||Ph.D. Thesis|
|Title:||Electronic Structure of Solid-State Dye-Sensitized Solar Cells: Synchrotron Induced Photoelectron Spectroscopy on Nanocrystalline TiO2, Newly Developed Dyes and Spiro-MeOTAD|
The goal of this work was to investigate the solid-state dye-sensitized solar cell. The work was intended to contribute to the basic understanding of the function of this type of solar cell. This included a better understanding of the materials used in the solid-state DSSC and their processing. Moreover, different factors influencing the efficiency of the solid-state DSSC were investigated. The issues were coordinated with the cooporation partners BASF and Bosch.
The main part of this work was to investigate the organic hole conductor Spiro-MeOTAD by synchrotron induced photoemission spectroscopy (SXPS). Spiro-MeOTAD is used as a substitution for the liquid iodide/triiodide redox couple in solid-state dye-sensitized solar cells. For the in-situ preparation and measurement, drop-casting was used to deposit Spiro-MeOTAD wet chemically. Drop-casting is a method close to spin-coating which is normally used in industry. Because interface experiments can hardly be performed with drop-casting, PVD as a method which is suitable for interface experiments was applied. In order to investigate the equality of both methods, drop-casting and PVD were compared. Furthermore, the poor conductivity of Spiro-MeOTAD makes it necessary to dope the hole conductor. Therefore, the doping mechanisms of the dopants Li-TFSI and WO3 were investigated. Li-TFSI is a dopant widely used for Spiro-MeOTAD in solid-state DSSCs and WO3 was chosen as a model system. Furhermore, the interfaces of Spiro-MeOTAD to the substrate TiO2, different dyes and gold which is used as the back-contact in solid-state DSSCs were of special interest as the energetic lineup determines the efficiciencies of the solid-state DSSCs.
Another goal of this work was to determine the behavior and influence of sodium which is part of the TiO2 precursor on the solid-state DSSC. As TiO2 films prepared in different laboratories often lead to varying efficiencies of the cells using the same TiO2 precursor material and the same recipe, systematic ex-situ heat treatments using a hot plate and a heat gun were performed on different ex-situ prepared nc-TiO2 films.
Moreover, the influence of different anchor groups and additives on the energetic properties and allignments of ruthenium-free perylene dyes to the TiO2 electrode and the hole conductor Spiro-MeOTAD were investigated by SXPS.
|Place of Publication:||Darmstadt|
|Classification DDC:||500 Naturwissenschaften und Mathematik > 500 Naturwissenschaften
500 Naturwissenschaften und Mathematik > 530 Physik
600 Technik, Medizin, angewandte Wissenschaften > 620 Ingenieurwissenschaften
|Divisions:||11 Department of Materials and Earth Sciences
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences > Material Science > Surface Science
|Date Deposited:||12 Jun 2014 09:39|
|Last Modified:||12 Jun 2014 09:39|
|Referees:||Jaegermann, Prof. Dr. Wolfram and von Seggern, Prof. Dr. Heinz|
|Refereed:||9 April 2014|