ABSTRACT
In this chapter, the authors focus on their quest for such supramolecular bulk heterojunction-organic photovoltaics (BHJ-OPV) materials based on multiple hydrogen-bonding interactions. Without using the extended p-conjugated molecules, well-defined columnar nanostructures can be constructed from synthetically more accessible small molecular building blocks through programmed self-assembly processes, which would be a more cost-effective strategy for the development of small molecular BHJ-OPV. The authors review a series of their researches on the design, characterization, and photovoltaic properties of supramolecular nanorods self-assembled from barbiturated oligothiophenes. The organization of synthetically accessible π-conjugated small molecules through programmed self-assembly processes provides specifically designed nanostructures with desirable optoelectronic properties. The alkyl chains of organic semiconductors play important roles, not only in imparting enough solubility in organic solvent but also in stabilizing assembled structures. Although the longer alkyl chains deteriorate the two-dimensional organization of rosettes, they promote the formation of rod-like nanostructures by enhancing van der Waals interaction between rosettes.
