Novel Processes and Materials for Fabrication of Photovoltaic Devices
Kenneth Carter (Polymer Science & Engineering) and D. Venkataraman (Chemistry)

Nanostructured semiconductor materials exhibit interesting optical, electronic, and catalytic properties. Structured semiconductor films with dense arrays of features at the 10-50-nm scale have shown considerable promise for use in photovoltaic devices. Complex sub-micron patterns can be made by classic photolithography as well as newer methods such as microcontact printing of self-assembled monolayers, polymer brushes, block copolymer self-assembly and a variety of imprint techniques. Over the past several years we have developed a nano-contact molding (NCM) imprint lithographic technique for the replication of nm-scale features using functional crosslinked polymeric materials. This process offers many advantages in terms of cost and versatility.

We will use our NCM technique to create inorganic semiconductor nanostructures. Key organic molecules attached to the semiconductor surface will serve as a reactive layer with grafting sites for the in-situ polymerization. The covalent grafting of polymer to the TiO2 surface by this technique will ensure intimate contact between these two materials. We initiated this collaboration in 2008 and it has been a success. We have made exciting discoveries in the use of NCM to template substrates for the creation of useful inorganic structures. Much work needs to be done in this area and the REU students will be expected to continue to advance this exciting new area of research.

Imprinting of semiconductor nanostructures: An REU student in the Carter group will fabricate the semiconductor nanostructures by creating molds and transferring the mold patterns into the semiconductor nanostructures.

Synthesis of coupling reagents: An REU student in the Venkataraman group will prepare a series of coupling reagents to be attached to the semiconductor surface.

Collaborative effort: The two REU students will work together to apply the coupling reagents to the surface of the patterned semiconductor nanostructures in order to prepare the scaffolds (Figure 2), then perform surface analysis by UV-Vis, IR, ellipsometry and atomic force microscopy (AFM).

BACK TO INTERNSHIP RESEARCH PROJECTS