Dye sensitized solar cells – investigation of bis(diimine)copper(I) dyes

Our society with its modern lifestyle based on the dependency of technology is facing an energy problem associated with a climate crisis. With the extensive use of electronic devices the world´s energy demand increased tremendously. The limited availability of fossil fuels, which are mainly used to provide the energy needed cause the pollution of the environment. The urgent need to find a new, sustainable energy source focussed on harnessing the sun light the unlimited energy source. Silicon based photovoltaic devices are still the most established choice to capture solar energy but the requirement on highly pure materials for this devices is a drawback for cost efficient energy. Dye sensitized solar cells turn out to be a beneficial alternative since their manufacturing is much simpler and non-depending on the pureness of the material. However the best performing dye sensitized solar cells are based on ruthenium sensitizers. Replacing the rare and expensive ruthenium by more earth abundant and sustainable metals is the challenge and goal of our research group. This thesis describes the use of heteroleptic bis(diimine)copper(I) dyes to harvest sunlight.
Chapter 1 gives a short overview on the energy problem and introduces photovoltaic devices including the design and important device components of dye sensitized solar cells.
Chapter 2 describes general analytical methods, the preparation of solar cell devices and their characterization methods.
Chapter 3 shows the synthesis of different anchoring ligand and their application in dye sensitized solar cells in combination with different ancillary ligands.
Chapter 4 compares the device performance using two different anchoring ligands combined with asymmetric ancillary ligands. Furthermore the dye bleaching and regeneration is investigated.
Chapter 5 investigates the effects of ancillary ligands with different numbers of methoxy groups in bis(diimine)copper(I) dyes.
Chapter 6 the enhanced cell performance of substituents in the 4,4´-positions of the phenyl spacer in the ancillary ligands is further explored.
Chapter 7 shows the synthesis and device performance of 4-methoxycarbonyl phenyl and 4-ethylphenyl functionalized ancillary ligands.
Chapter 8 describes a preliminary study of all copper dye sensitized solar cells.
Chapter 9 reports a preliminary investigation of tandem dye sensitized solar cells.
Chapter 10 gives a short summary over the thesis.
Chapter 11 concludes the thesis and gives a short outlook for future investigations.