b'Orientation of Anthraquinone in Stretched PVC FilmsTyler BertochSponsor: Dr. Donna Gosnell, Department of ChemistryThe extent of orientation of anthraquinone embedded in stretched polyvinylchloride (PVC) films is measured by linear dichroism. The extent of orientation versus film stretch ratio and the linear dichroism (LD) are correlated to the known transition moment direction. The LD is also correlated to molecular shape.Application of Purple Yam Extract in Dye-Sensitized Solar CellsJoshua M. HardySponsor: Dr. Linda De La Garza, Department of ChemistryPurple yams (Dioscorea alata) are vegetables of vibrant color. The color arises from pigments called anthocyanins and anthocyanidins. Pigments were extracted from dehydrated purple yam powder using acidified aqueous solution. A purple solution was obtained after filtration. The pigments in the solution were characterized by measuring the absorbance at 300-800 nm with a UV-VIS spectrophotometer. Several peaks were detected in the spectrum, and the main peak at 535 nm matches known values for anthocyanins of purple yams. This extract will be used to sensitize semiconductors in nanocrystalline solar cells to increase their absorption range through light-induced electron transfer mechanisms. The photocurrent and photovoltage characteristics will be recorded for the practical application of natural pigments in solar cells.31'