The use of organic semiconductors (OSCs), i.e, conductive polymers, has risen greatly over the last few decades, as scientists have taken advantage of their unique properties, including greater mechanical flexibility, lower costs, and more simple processing compared to inorganic semiconductors like silicon. They are commonly used in organic light-emitting diodes (OLEDs), with further research going on into how they can be improved in photovoltaics and biotechnologies. Developing these high-performance OSCs depends on effective n-type (adding electrons) and p-type (adding vacancies) doping of polymers to enhance their electrical conductivity; however, n-doped OSCs lag behind their p-doped counterparts in terms of conductivity and stability, which calls for research into better-performing n-doped polymers. In an effort to contribute to this n-doping development, this work takes the polymer PBTTT-C14, which is commonly p-doped, and combines it with the ruthenium dimer (RuCp*Mes)2, a powerful n-dopant used in our lab, to evaluate feasibility and performance. Results show that this is indeed a suitable doping mechanism, and a maximum conductivity of 1.05x10-4 S/m can be achieved by increasing dopant concentration, increasing temperature, and exposing the material to UV light. At the same time, the morphology of n-doped PBTTT-C14, or structure of molecules in the material, becomes a challenge since traditional techniques for gaining a uniform morphology are ineffective, which harms the conductivity. Despite this, n-doped PBTTT-C14 is comparable to p-doped PBTTT-C14 prepared in a similar manner, which is encouraging for the prospects of this dopant-polymer combination.

Colin Brown, '24: https://www.linkedin.com/in/colin-b-brown/