Scrutinizing the Role of Ambipolar Units in the Donor-Acceptor Framework
View/ Open
Abstract
Conjugated polymers (CPs) are a class of materials that contradict what is commonly considered when people hear the terms plastics and electronics. While these two phrases are generally considered exclusive, CPs combine the optical and electronic properties of inorganic materials and the flexibility and processability of traditional organic polymers and plastics. Research into CPs has resulted in an improved understanding of these compounds, leading to its application in the form of organic photovoltaics, organic light-emitting diodes, sensors, electrochromics, and field effects transistors. During this time, a number of models were developed for designing these polymers with desired characteristics, with the donor-acceptor framework becoming the most widely used model. This model utilizes electron-rich donor units and electron-deficient acceptor units that generate a material with a reduced energy difference between its frontier orbitals.
Thieno[3,4-b]pyrazine (TP) based compounds are compounds used by the Rasmussen group and have distinct characteristics that has deemed it necessary to give it a new classification of an ambipolar unit within the donor-acceptor framework. TP has been previously classified as an acceptor unit within the donor-acceptor framework, but it has been shown to behave as both an acceptor and a donor simultaneously. In an effort to understand how the ambipolar unit behaves when paired with donor and acceptor units, a family of dimers was generated to determine the role of the ambipolar unit. Based on the findings from the dimer family, polymers of an alternating TP unit and different acceptors were generated to form a new family of acceptor-ambipolar polymers that also have desirable electronic characteristics with respect to the band gap and energy levels. This work provides a new insight on evaluating monomer units within the donor-acceptor framework as well as establishing a viable alternative for polymer design using ambipolar units.