Surface Functionalization of ZnO Reuben T. Collins, Colorado School of Mines, DMR 0606054

1. Surface Functionalization of ZnO Reuben T. Collins, Colorado School of Mines, DMR 0606054 Metal oxide nanostructures are under active investigation for hybrid organic/inorganic device applications. Performance is limited, however, by an inability to control both the structural and electronic characteristics of the interface. To address this issue, a siloxane-based molecular monolayer functionalization of the ZnO surface has been demonstrated using octadecyltriethoxysilane (OTES). The monolayer creates a stabilized hydrophobic (0001) ZnO surface. When coated with the semiconducting polymer, poly(3-hexylthiophene), improved polymer ordering and charge transfer across the interface are observed. Using triexthoxysilane-based molecules with different organic end groups, the same attachment strategy can be used to tune the chemistry of the ZnO surface for different applications. UV ozone cleaned OTES treated Toluene cleaned Water contact angles on ZnO surfaces with different surface treatments. Infrared absorption of C-H stretch modes on OTES treated ZnO surfaces. A treated silicon surface is shown for comparison. Variations in integrated intensity correlate with surface coverage.

2. Undergraduate Education Through Research ExperiencesReuben T. Collins, Colorado School of Mines, DMR 0606054 The PIs have strong belief in the value of educating undergraduates through participation in open-ended research projects. In the last year a team of three seniors thesis students and two summer REU students have participated, as true team members, in this project. Since molecular monolayer control of surface properties of nanostructures is a central theme of the work, several of the students focussed on synthesis and control of ZnO nanostructures. The senior thesis team presented their work at the 2007 March Meeting of the American Physical Society. One of the summer REU students is preparing a poster for the annual meeting of the Rocky Mountain Chapter of the AVS. Absorption and photoluminescence spectra of uncapped and octanethiol capped ZnO quantum dots. Hydrothermally grown ZnO nanowire “carpet.”