Morphology Control in Polymer Light Emitting Diodes and Molecular Bulk-heterojunction Photovoltaics
Author | : Kenneth R. Graham |
Publisher | : |
Total Pages | : |
Release | : 2011 |
Genre | : |
ISBN | : |
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The D-A-D based oligomers are observed to readily form aggregates that lead to decreases in device performance. To combat this problem, oligomers with bulky or cross-linkable end-groups are incorporated into PLEDs. Although neither strategy is shown to reduce aggregation, the cross-linkable systems allow for solution-processed multilayer PLEDs to be obtained. The family of Pt-porphyrins incorporated into PLEDs was designed with two primary purposes; extending the emission wavelength further into the near-IR and optimizing the molecular structure to both decrease aggregation and increase quantum yield. The second portion of this dissertation focuses on controlling morphology in solution-processed molecular BHJ photovoltaic cells through two different methods. The first method involves the incorporation of solvent additives with known solubility parameters to develop a predictable method of morphology control. The second method involves the use of asymmetric oligomers to more predictably control the crystallization kinetics and thus provide the ability to finely tune the film morphology.