Doctor of Philosophy (PhD)
Renewable energy is a major concern due to increased world energy consumption. In particular, solar energy is a type of renewable energy source that uses devices known as solar cells to convert sunlight to electricity. Specifically, devices referred to as dye-sensitized solar cells (DSSCs) employ dyes to absorb solar energy. Dyes derived from ruthenium complexes have been typically used in DSSCs. Unfortunately, several disadvantages are associated with current ruthenium complex photosensitizers, which can be attributed to limited supply and expense of metals, as well as reduced absorption in the near-infrared region of the electromagnetic spectrum. Accordingly, this dissertation is a discussion of novel dyes referred to as group of uniform materials based on organic salts (GUMBOS) for application as photosensitizers in DSSCs. These GUMBOS are solid phase organic salts composed of bulky ions that have melting points from 25°C to 250°C. Importantly, GUMBOS can be tuned for multiple functions based on selected ions resulting in interesting physiochemical properties. In addition, nanomaterials derived from GUMBOS (nanoGUMBOS) can also result in significant properties. The first part of this dissertation involves the synthesis and characterization of nanoGUMBOS from cyanine dyes. These nanomaterials are prepared via a facile self-assembly approach, and spectral and electrochemical properties are investigated. In one study, controlled properties of cyanine-based nanoGUMBOS are found to be dependent on the counterion associated with the cationic dye. In another study, GUMBOS derived from cyanine dyes with increasing methine chain lengths are synthesized. In addition, binary nanomaterials consisting of two different cyanine methine chain length GUMBOS are prepared. The effect of Förster resonance energy transfer between these latter nanomaterials enhances fluorescence into the near-infrared region of the electromagnetic spectrum. The individual and binary nanoGUMBOS offer possible use as sensitizers that extend into the near-infrared region of the electromagnetic spectrum. The second part of this dissertation entails the incorporation of cyanine-based GUMBOS and nanoGUMBOS into DSSCs. In this study, various preparation methods are used for formation of titanium dioxide semiconductor electrodes. Solar cells comprised of these electrodes and cyanine-based GUMBOS are fabricated, and the performances of these DSSCs are investigated.
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Jordan, Atiya Nicole, "GUMBOS and NanoGUMBOS: Applications as Photosensitizers in Dye-sensitized Solar Cells" (2013). LSU Doctoral Dissertations. 3190.