Molecular Engineering of D-π-A Dyes for Dye-Sensitized Solar Cells

Sammanfattning: Dye-sensitized solar cells (DSSCs) present an interesting method for the conversion of sunlight into electricity. Unlike in other photovoltaic technologies, the difficult tasks of light absorption and charge transport are handled by two different materials in DSSCs. At the heart of the DSSC, molecular light absorbers (dyes) are responsible for converting light into current.In this thesis the design, synthesis and properties of new metal-free D-π-A dyes for dye-sensitized solar cells will be explored. The thesis is divided into six parts:Part one offers a general introduction to DSSCs, dye design and device characterization.Part two is an investigation of a series of donor substituted dyes where structural benefits are compared against electronic benefits.In part three a dye assembly consisting of a chromophore tethered to two electronically decoupled donors is described. The assembly, capable of intramolecular regeneration, is found to impede recombination.Part four explores a method for rapidly synthesizing new D-π-A dyes by dividing them into donor, linker and acceptor fragments that can be assembled in two simple steps. The method is applied to synthesize a series of linker varied dyes for cobalt based redox mediators that builds upon the experience from part two.Part five describes the synthesis of a bromoacrylic acid based dye and explores the photoisomerization of a few bromo- and cyanoacrylic acid based dyes.Finally, in part six the experiences from previous chapters are combined in the design and synthesis of a D-π-A dye bearing a new pyridinedicarboxylic acid acceptor and anchoring group.