Please use this identifier to cite or link to this item: http://scholarbank.nus.edu.sg/handle/10635/29529
Title: Design and synthesis of donor acceptor hybridized small molecules and graphene derivatives for photovoltaic and optical studies
Authors: ANUPAM MIDYA
Keywords: OPV, Graphene, Phenothiazine, Otical limiting, Carbazole, Solar cell
Issue Date: 7-Jan-2011
Source: ANUPAM MIDYA (2011-01-07). Design and synthesis of donor acceptor hybridized small molecules and graphene derivatives for photovoltaic and optical studies. ScholarBank@NUS Repository.
Abstract: The limited energy source and environmental problems created by greenhouse gases and other pollutants from detrimental fossil fuel by product provides the driving force for researching on renewable energy source- solar energy. In the first part of this thesis, the fundamentals of organic photovoltaics are discussed followed by introducing three types of organic semiconducting materials and their applications in organic solar cells. In the second chapter of this thesis, a series of small molecules have been synthesized and attempted them in molecular bulkheterojunction (BHJ) solar cell. The band gap energy of the small molecules can be tuned according to the strength of the donor moiety. The special configuration of phenothiazine donor moiety improves the film-making properties. In chapter 3, a novel donor-spacer-acceptor (D-pi-A) type organic dye has been synthesized using phenothiazine donor, vinyl-bithiophene spacer and cyanoacrylic acid acceptor and highly efficient dye-sensitized solar cell (DSSC) have been fabricated using liquid electrolyte. Structural modification by introducing two donor moieties to the D-pi-A system improves the photoabsorption capacity but does not lead to improvement of efficiency. To address the problem associated with liquid electrolyte in DSSCs, a new class of solid state ionic conductor as electrolyte for solid-state dye sensitized solar cell (SDSC) has been developed in chapter 4. The well-known hole conductor carbazole is attached to imidazolium iodide structure and successfully deployed as solid state ionic conductor in SDSCs. The combined solid state ionic conductors and iodine electrolytes provides dual channels for hole/triiodide transportation in SDSC. In the last part of this thesis, a generic functionalization method based on Suzuki coupling and diazonium coupling has been developed to synthesize graphene-polymer hybrids. Reduced graphene oxide sheets are grafted with semiconducting D-pi-A type polymer. Although these hybrids do not show useful photovoltaic response, they exhibit more superior optical limiting properties compared to benchmark optical limiting materials.
URI: http://scholarbank.nus.edu.sg/handle/10635/29529
Appears in Collections:Ph.D Theses (Open)

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