A Freely Soluble, High Electron Affinity Molecular Dopant for Solution Processing of Organic Semiconductors

Molecular dopants are increasingly studied to enhance the conductivity of semiconducting polymers. Most available p-type dopants have low solubility in common solvents and moderate electron affinities (EA), which makes solution processing difficult and limits the range of semiconducting polymers that can be doped. Here, we describe the synthesis and characterization of the new molecular dopant TMCN3-CP, which has an EA of −5.5 eV. We show that high ionization energy alternating copolymers such as PDPP-4T, PDPP-3T, and PDPP-T-TT-T can be p-type doped and achieve high conductivities with TMCN3-CP using sequential solution processing. The main advantage of this new dopant is the ability to chemically tailor the ester groups, which we demonstrate here for sequential solution doping of films. Sequential solution processing allows a greater ability to control the film morphology and is also desirable for scale-up to large-area polymer electronics.