Organic Semiconductors

The use of solution flow as a means to synthesize aligned polyelectrolyte-surfactant nanofibers using layer-by-layer (LbL) deposition methods was also explored in our labs. In these studies, we first demonstrated that the self-assembly of charged perylene diimide dyes (small molecule organic semiconductors) and oppositely charged polyelectrolytes leads to formation of composite nanofibers.[54,62] Semi-aligned nanofibers were shown to be produced when dip-coating based methods were employed under certain conditions,[71] while much better alignment was obtained when microfluidic devices were employed during LbL deposition.[73] Our unique contributions here include our observation that flow alignment could only be achieved for unique, asymmetrically-substituted (i.e., surfactant-like) perylene diimides synthesized in our labs.[71,73] Symmetrically substituted dyes showed no evidence of nanofiber alignment. The methods and materials developed in this project may have applications in organic solar cells and other organic electronics.

Reference numbers refer to articles in the Higgins Group publication list