Identifier

etd-04042016-203043

Degree

Doctor of Philosophy (PhD)

Department

Chemistry

Document Type

Dissertation

Abstract

In this dissertation, development of new materials to the field of photonics, more specifically solar energy conversion and cancer therapy was studied. In particular, a series of group of uniform materials based on organic salts (GUMBOS) were developed for use as improved photosensitizers in dye-sensitized solar cells (DSSCs) and photodynamic therapy (PDT). GUMBOS are solid phase organic salts that are similar to ionic liquids, but with melting points ranging from 25 to 250 °C. Properties of GUMBOS can easily be tuned by changing the cation or anion used to form these materials. Thus, new materials can easily be produced with properties that are beneficial for applications in DSSCs or PDT. In this dissertation, porphyrin-based GUMBOS as well as nanomaterials derived from these GUMBOS (nanoGUMBOS) were synthesized and characterized as photosensitizers in DSSCs. These GUMBOS and nanoGUMBOS displayed interesting properties such as increased molar absorptivity and broadened absorption spectra, which are important characteristics for photosensitizers used in DSSCs. NanoGUMBOS-based photosensitizers were applied in DSSCs after precise optimization of the DSSCs structure with regard to the semiconductor (working electrode) and electrolyte. In another application, GUMBOS were developed as energy relay dyes (ERDs) in DSSCs due to the tunable properties of GUMBOS such as solubility, molar absorptivity, and fluorescence quantum yield. GUMBOS-based ERDs were applied in DSSCs, and increases in solar conversion efficiencies of up to 14.6% were observed. Interestingly, the magnitude of increase in solar conversion efficiency was found to depend on the counterion used in synthesis of GUMBOS-based ERDs. Finally, porphyrin- and phthalocyanine-based nanoGUMBOS were studied for application as photosensitizers in PDT. By using a facile, ion exchange reaction to form GUMBOS, a bulky cation was introduced to prevent aggregation of porphyrin and phthalocyanine dyes. Overall increases in singlet oxygen production were observed with GUMBOS in comparison to the parent compounds. Singlet oxygen quantum yields of porphyrin and phthalocyanine GUMBOS were 0.57 ± 0.05 and 0.55 ± 0.01 in comparison to yields from the parent dyes, which were 0.50 ± 0.02 and 0.46 ±0.04, respectively. As a whole, these studies demonstrate substantial advantages of GUMBOS-based materials in the field of photonics.

Date

2016

Document Availability at the Time of Submission

Secure the entire work for patent and/or proprietary purposes for a period of one year. Student has submitted appropriate documentation which states: During this period the copyright owner also agrees not to exercise her/his ownership rights, including public use in works, without prior authorization from LSU. At the end of the one year period, either we or LSU may request an automatic extension for one additional year. At the end of the one year secure period (or its extension, if such is requested), the work will be released for access worldwide.

Committee Chair

Warner, Isiah

Available for download on Friday, January 01, 9999

Included in

Chemistry Commons

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