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Improving the efficiency of next-generation solar cells is crucial to their commercialization. This thesis presents a novel approach to coupled organic-inorganic nanostructures through in-situ polymerization of a ligand, creating an extended, delocalized sp2 environment surrounding lead sulfide (PbS) quantum dots in a thin film. Through the design of this novel, in-situ polymerizing ligand, ligand exchange dynamics are explored by looking at terminal alkynes, primary amines, and carboxylic acids as anchoring moieties. Using Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Photoelectron Spectroscopy (XPS), it is shown that terminal alkynes and primary amines do not coordinate to PbS quantum dots, and that ligands containing sp-hybridized bonds can influence the band position of thin films through successful coordination via a carboxylic acid coordinating group. A proof-of concept diacetylene ligand, dodeca-5,7-diynedioic acid (D57DDA) is synthesized and coordinated to PbS quantum dots, confirmed through the use of XPS. In-situ polymerization of the diacetylene ligand is confirmed using FTIR and XPS. Finally, solar cells incorporating the novel D57DDA ligand are fabricated and compared to PbS quantum dot control devices. Devices using the coupled organic-inorganic nanostructure as the hole-transport layer show comparable device efficiencies to control devices at 4%, with performance improving with increased UV exposure. This is hypothesized to be due to the polymer’s band alignment with the quantum dots leading to efficient charge transfer of holes and increased mobility through the hole-transport layer. Impurities, believed to be chloride ions introduced in the ligand synthetic isolation, are shown to improve device performance with their absence reducing short circuit current. |
