Enhancement of Interfacial Polymer Crystallinity Using Chromism in Single Inorganic Nanowire-Polymer Nanohybrids for Photovoltaic Applications

Interfaces play an important role in bulk heterojunction organic/inorganic hybrid photovoltaic devices, but directly probing the interface in order to improve device characteristics is exceedingly difficult. We report on a method to form core-shell inorganic nanowire-polymer hybrids of a conducting polymer, poly(3-hexIthiophene-2,5-diyl) (P3HT), and a semiconducting nanowire, cadmium sulfide (CdS), using solution processing to create the polymer shell around the nanowire in order to study the polymer-nanowire interface directly without interference from bulk effects. We have used the rod-coil transition (chromism) in P3HT to seed and enhance the crystallinity at the polymer-nanowire interface. We have shown that creating more order within the P3HT main chain, by controlling the temperature and the solvent quality, can increase the extent of polymer crystallinity present at the polymer-nanowire interface. We believe using the rod-coil transition to create more order in P3HT and the resulting polymer-nanowire interface will provide a facile pathway for designing future organic-inorganic photovoltaic devices.