Date of Award
Chemistry and Biochemistry
Diketopyrrolopyrroles, Single material solar cells, Donor-acceptor dyads
Although diketopyrrolopyrroles (DPPs) have been extensively studied as organic pigments and dyes and as building blocks for molecular and polymeric organic electronic materials, their propensity for self-organization has been given surprisingly little attention. Self-organization provides control over the morphology and supramolecular structure of materials and, consequently, the performance of a material. The dependence of performance on supramolecular structure is particularly delicate in bulk heterojunction organic solar cells and the emerging low-cost single material organic solar cells (SMOSC). Most donor-acceptor dyads and triads presently developed for SMOSCs consist of dyes as electron donors and fullerene derivatives as electron acceptors, but their supramolecular packing and morphologyis usually ill defined. Presented in this thesis is the design and synthesis of a self-organizing DPP derivative that could be used as an e-donor component in DA dyads and ADA triads with fullerene derivatives as e-acceptors. The targeted DPP reference compound was prepared in good to fair yields and contains two 3,5-didodecyloxybenzoic ester groups as placeholders for fullerene ester derivatives. The 3,5-didodecyloxybenzoic ester groups induce columnar mesomorphism between below -50°C and 205°C and strong π-π staking interactions are observed in both soft crystal and liquid crystal columnar mesophases based on variable temperature powder XRD, differential scanning calorimetry, and polarized optical microscopy. Also favourable for its application in dyads and triads for SMOSCs arethe absorption properties, orbital energies, and solubility of this DPP derivative. Orbital energies were estimated based on the optical gaps and the redox potentials determined by cyclic voltammetry in solution. Future work will focus on the substitution of one or both benzoic ester groups with fullerene containing ester groups for device tests in SMOSCs.
Cassar, Adam M., "Diketopyrrolopyrrole Derivatives for Single Material Solar Cells" (2022). Electronic Theses and Dissertations. 8801.