Rachel Hoffman '11

Upon her arrival, Rachel Hoffman ‘11 took advantage of much that Cornell had to offer. An avid member of the Big Red Pep Band, teaching assistant, engineering ambassador, Tau Beta Pi member and researcher, Rachel found that Cornell offered a well-rounded undergraduate experience as well as a highly regarded technical degree.

Coming to Cornell from Lexington, Massachusetts, Rachel used her love for math and chemistry as a compass to guide her to engineering, but it was Professor Duncan’s Introduction to Chemical Engineering class that drew her to affiliate with chemical engineering and later to serve as a teaching assistant for the class. The versatility and chaos of the field enticed her to become more involved with the variety of branches of research that chemical engineering offers.

As an undergraduate, Rachel worked on photovoltaics research with three different research groups. During the spring of her sophomore year, she joined the Clancy group in CBE, working on simulations of fullerene on pentacene for semiconductor applications. This initial work led her to participate in the National Nanotechnology Infrastructure Network Research Experience for Undergraduates (NNIN REU) program at the University of Minnesota during the summer following her sophomore year. There, her project focused primarily on solar cells with copper zinc tin sulfide as the p-type semiconductor and zinc sulfide as the ntype
semiconductor.

Upon returning to Cornell for her junior year, she chose to continue her work with photovoltaics in a new setting: the Hanrath group. Since then, she has worked primarily on two projects relating to lead sulfide nanocrystal solar cells.

She now acts as the lead researcher on the first project, which she presented at the fall 2010 Materials Research Society (MRS) Conference in Boston. This project team studies solar cell performance in relation to varying conductivity levels exhibited through the use of tosylate doped poly(3,4-ethylenedioxythiophene) (PEDOT) in place of poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) as the hole conducting layer. With another undergraduate and a graduate student, Rachel undertook a second project, this one analyzing tandem nanocrystal solar cells. The team successfully demonstrated the first tandem nanocrystal solar cell. Now they are working on a journal publication that will report these findings.

Despite her busy schedule with class, research and teaching, Rachel always manages to find time for her other passions. “Pep band is my outlet; it keeps me sane,” she says about playing the piccolo at Big Red sporting events. Playing with the pep band has given her opportunities to attend high demand campus events, such as Harvard Hockey at Cornell, and even to travel with the teams. “I went to March Madness last year,” she reports with excitement. “They chartered a plane out of Ithaca for the team, the cheerleader’s and the pep band. So we got to fly direct to Jacksonville on a plane much bigger than anything that’s ever flown out of Ithaca!”

After her graduation in May, Rachel will work toward her Ph.D., and she’ll continue to pursue her interests in materials science and electronic polymers. “When I affiliated, I liked that fact that I could get a good job right after I graduated if I wanted to. But then I started doing
research and decided I wanted to go to graduate school, so I won’t be getting that job for five more years now.”