home > TRiO and USP Programs > McNair > symposium > 2006 presentations > Richard Fuller

Richard Fuller
Chemistry

Mark Lonergan, Mentor

How Contact Work
Function Affects Conductivity

Nanocomposites consisting of PbS nanocrystals in a conjugated polymer matrix will be fabricated in an effort to optimize photocells based on colloidal nanocrystals / conjugated polymer blends in a Metal-Insulator-Metal type structure. The device consists of a sandwich structure of glass, indium tin oxide (ITO), poly (p-phenylenevinylene) (PPV), MEH-PPV/PbS nanocrystal blend, and an upper magnesium contact. The Mg and ITO serve the role of metal and the MEH-PPV / nanocrystal blend the insulator. These active optoelectronic materials produce and harvest light efficiently in the visible spectrum. Sargent and co-workers reported photoconductivity at infrared wavelengths, 975-1300 nm, from a polymer/nanocrystal quantum dot composite. The principal issue under investigation concerns how the work-function difference between the metals in the metal structure affects the efficiency by which the above device can convert light into electricity.