Manipulating Excited State Energy Flow in Organic Systems using Radical Polymers
Technical Report,15 Sep 2015,14 Sep 2018
Purdue University West Lafayette United States
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Controlling charge and energy transport in closed-shell conjugated polymers has been a subject of intense study for a number of years however, implementing a molecular design archetype that includes open-shell i.e., radical materials has been extremely limited. Conversely, we demonstrate that the inclusion of radical-containing materials provides significant means by which to manipulate these charge and energy landscape profiles if the macromolecular open-shell designs are synthesized in the appropriate manner. Moreover, these molecular design motifs were evaluated in three end-use applications that are of potential interest to the Department of Defense. We designed open-shell materials and evaluated their performance as 1 charge- and energy-accepting moieties from conjugated polymers that had been photoexcited 2 interfacial modifiers between semiconducting layers and metallic contacts in solar cells and organic field-effect transistors and 3 dopants for thermoelectric conjugated polymers. Importantly, three overarching themes emerged from this work. First, the mechanism associated with energy transfer between photoexcited conjugated polymers and open-shell additives was established. Second, the design rules for creating radical polymers with high electrical conductivity values was elucidated in full. Third, open-shell dopants offer a means by which to increase the electrical conductivity of conjugated polymers while having minimal impact on the thermopower of the conjugated polymers. Therefore, this is foundational work for an emerging research field i.e., that of radical-containing organic electronics, and we demonstrated that we can design, synthesize, and manipulate the physical chemistry associated with open-shell species in order to enhance performance in materials and devices of interest to the defense community.
- Electricity and Magnetism
- Electrical and Electronic Equipment
- Polymer Chemistry