Polymer Infiltration of ZnO NanowiresR. T. Collins and T. E. Furtak, Colorado School of Mines, DMR 0606054

ZnO nanowire arrays provide an ideal geometry for charge collection in hybrid nanowire/polymer solar cells. Solution synthesized nanowire arrays, however, expose a polar end face in the (0001) direction, which polymers wet poorly. When polymer is spun onto untreated nanowires, it does not penetrate the array. We have developed a chemistry for attaching the family of triethoxysilane (TES) molecules to the ZnO surface1 using an approach originally developed for attachment to glass. The process relies on an amine catalyst in conjunction with a hydroxylated surface to limit molecular bonding and cross-linking to only the metal oxide surface. Treatment of nanowire arrays with phenyltriethoxysilane (PTES) changes the ZnO surface energy and improves polymer wetting, leading to complete intercalation. This research demonstrates the critical importance of controlling surface/interface properties.

The polymer poly(3-hexylthiophene) sits on the surface of an untreated ZnO nanowire array (green arrow) but fully penetrates an array functionalized with PTES.

PTES treated

Untreated

1Allen et al., accepted for publication in Langmuir (2008)

Graduate student Jamie Albin presents “How cold is cold” to elementary and middle school teachers.

AFM image of mono-atomic terraces on ZnO, prepared and measured by undergraduate Heather Oertli

K-12 Outreach, Undergraduate Research and International Experience

R. T. Collins and T. E. Furtak, Colorado School of Mines, DMR 0606054

ZnO nanowire “carpet” prepared in Norway by undergraduate Matt Bergren

Tom Furtak demonstrates refraction that happens in a rainbow to a middle school teacher.