Push-Pull Molecules: Models and Polymer Building Blocks for Organic Photovoltaic Applications

PUSH-PULL MOLECULES: MODELS AND POLYMER BUILDING BLOCKS FOR ORGANIC PHOTOVOLTAIC APPLICATIONS FEBRUARY 2014 RAYMOND DEVAUGHN, B.S., UNIVERSITY OF THE DISTRICT OF COLUMBIA M.S., UNIVERSITY OF MASSACHUSETTS AMHERST Directed by: Professor Paul M. Lahti Several fluorenone alkynyl based oligo conjugated molecules were synthesized and characterized. Most compounds exhibited UV---Vis absorption onset at ca. 500 nm and a PL emission onset of ~329---370 nm, with excimer emission suspected from most systems near ~530---560 nm. Experimentally determined EHOMO and ELUMO energies range from --6.02 to ---5.73 eV and ---3.47 and 3.55 eV, respectively, with the lowest experimental Eg lying at ---2.26 eV for 2---(trimethoxyphenylacetylene)---fluorenone. Cyclic voltammetry indicates quasi---reversible reduction for all systems, with 2,7--bis(nitrophenylacetylene)fluorenone exhibiting a high reduction potential of ---1.25 eV. Only 2,7---bis(trimethoxyphenylacetylene)fluorenone exhibited a quasi---reversible oxidation, due to electron rich methoxy substituents. Diketopyrrolopyrrole systems as electron acceptors were also explored.